Floating Point: Manual Unrolling or Autovectorisation?

Java is very strict about floating point arithmetic. There’s even a keyword, strictfp, which allows you to make it stricter, ensuring you’ll get a potentially less precise but identical result wherever you run your program. There’s actually a JEP to make this the only behaviour. JLS 15.18.2 states clearly that floating point addition is not associative in Java, which means that JIT compilers have to respect the order of double[]s and float[]s when compiling code, even if it turns out the order is actually arbitrary to the application. This means they can’t vectorise or even pipeline loops containing interdependent floating point addition, can’t distribute multiplications over additions, can’t telescopically collapse multiplications: the list goes on. If you want this code to go faster you must work around the JIT compiler somehow. In C++, it’s possible to choose to treat floating point numbers as if they had the algebraic properties of the Reals. Using this option is often maligned, perhaps because it assumes much more than associativity, and applies to entire compilation units. A proposal for fastfp semantics at a class and method scope was withdrawn a long time ago.

Prior to the arrival of the Vector API, I’m interested in which vectorisation transformations are possible automatically. This is because I’ve found that many bottlenecks in applications are related to low single threaded performance, and others come from the premature usage of threads to solve these performance problems. Imagine how powerful multithreading could be if used only after saturating the intensity available on each core?

There are certain things you just can’t do in Java because of the language specification, and one of these is getting C2 to pipeline two or more dependent vpaddd instructions, so the maximum achievable floating point intensity is quite low. In fact, you can be better off giving up on autovectorisation and unrolling the loop yourself, allowing the pipelining of scalar additions. This depends intimately on your microarchitecture.

Double Precision Sum Product

C2 can automatically vectorise a sum product between two double[]s. It does this by issuing eight vmovdqu loads at once, then four vpmulpd multiplications at once, and then a long in-order scalar reduction. It does this with the simplest possible code, potentially rewarding simplicity with decent performance:


  @Benchmark
  public double vectorisedDoubleSumProduct() {
    double sp = 0D;
    for (int i = 0; i < xd.length && i < yd.length; ++i) {
      sp += xd[i] * yd[i];
    }
    return sp;
  }

Perfasm shows the problematic scalar reduction quite clearly:


....[Hottest Region 1]..............................................................................
c2, com.openkappa.simd.sumproduct.generated.SumProduct_vectorisedDoubleSumProduct_jmhTest::vectorisedDoubleSumProduct_thrpt_jmhStub, version 164 (238 bytes) 

           0x00000144f724f8e9: mov     r8d,r9d
           0x00000144f724f8ec: add     r8d,0fffffff1h
           0x00000144f724f8f0: cmp     r9d,r8d
           0x00000144f724f8f3: mov     edx,80000000h
           0x00000144f724f8f8: cmovl   r8d,edx
           0x00000144f724f8fc: cmp     r11d,r8d
           0x00000144f724f8ff: jnl     144f724f7dfh
           0x00000144f724f905: nop     word ptr [rax+rax+0h]  ;*iload_3 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::vectorisedDoubleSumProduct@13 (line 43)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_vectorisedDoubleSumProduct_jmhTest::vectorisedDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  0.00%    0x00000144f724f910: vmovdqu ymm1,ymmword ptr [rsi+r11*8+70h]
  1.07%    0x00000144f724f917: vmovdqu ymm2,ymmword ptr [rax+r11*8+70h]
  2.49%    0x00000144f724f91e: vmovdqu ymm3,ymmword ptr [rsi+r11*8+50h]
  0.67%    0x00000144f724f925: vmovdqu ymm4,ymmword ptr [rax+r11*8+50h]
  0.75%    0x00000144f724f92c: vmovdqu ymm5,ymmword ptr [rsi+r11*8+30h]
  0.01%    0x00000144f724f933: vmovdqu ymm6,ymmword ptr [rax+r11*8+30h]
  1.52%    0x00000144f724f93a: vmovdqu ymm7,ymmword ptr [rsi+r11*8+10h]
                                                         ;*daload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::vectorisedDoubleSumProduct@34 (line 44)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_vectorisedDoubleSumProduct_jmhTest::vectorisedDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  0.01%    0x00000144f724f941: vmovdqu ymm8,ymmword ptr [rax+r11*8+10h]
           0x00000144f724f948: vmulpd  ymm9,ymm2,ymm1
  0.02%    0x00000144f724f94c: vmulpd  ymm7,ymm8,ymm7
  1.50%    0x00000144f724f950: vmulpd  ymm8,ymm4,ymm3
  0.02%    0x00000144f724f954: vmulpd  ymm10,ymm6,ymm5
  0.00%    0x00000144f724f958: vaddsd  xmm0,xmm0,xmm7
  1.51%    0x00000144f724f95c: vpshufd xmm1,xmm7,0eh
  0.00%    0x00000144f724f961: vaddsd  xmm0,xmm0,xmm1
  5.91%    0x00000144f724f965: vextractf128 xmm4,ymm7,1h
  0.01%    0x00000144f724f96b: vaddsd  xmm0,xmm0,xmm4
  6.56%    0x00000144f724f96f: vpshufd xmm1,xmm4,0eh
  0.01%    0x00000144f724f974: vaddsd  xmm0,xmm0,xmm1
  5.75%    0x00000144f724f978: vaddsd  xmm0,xmm0,xmm10
  5.71%    0x00000144f724f97d: vpshufd xmm4,xmm10,0eh
  0.00%    0x00000144f724f983: vaddsd  xmm0,xmm0,xmm4
  5.89%    0x00000144f724f987: vextractf128 xmm6,ymm10,1h
  0.01%    0x00000144f724f98d: vaddsd  xmm0,xmm0,xmm6
  6.01%    0x00000144f724f991: vpshufd xmm4,xmm6,0eh
  0.01%    0x00000144f724f996: vaddsd  xmm0,xmm0,xmm4
  5.95%    0x00000144f724f99a: vaddsd  xmm0,xmm0,xmm8
  5.98%    0x00000144f724f99f: vpshufd xmm1,xmm8,0eh
  0.01%    0x00000144f724f9a5: vaddsd  xmm0,xmm0,xmm1
  5.99%    0x00000144f724f9a9: vextractf128 xmm5,ymm8,1h
  0.00%    0x00000144f724f9af: vaddsd  xmm0,xmm0,xmm5
  5.93%    0x00000144f724f9b3: vpshufd xmm1,xmm5,0eh
  0.00%    0x00000144f724f9b8: vaddsd  xmm0,xmm0,xmm1
  6.05%    0x00000144f724f9bc: vaddsd  xmm0,xmm0,xmm9
  5.92%    0x00000144f724f9c1: vpshufd xmm3,xmm9,0eh
  0.00%    0x00000144f724f9c7: vaddsd  xmm0,xmm0,xmm3
  6.05%    0x00000144f724f9cb: vextractf128 xmm2,ymm9,1h
  0.00%    0x00000144f724f9d1: vaddsd  xmm0,xmm0,xmm2
  6.05%    0x00000144f724f9d5: vpshufd xmm3,xmm2,0eh
  0.00%    0x00000144f724f9da: vaddsd  xmm0,xmm0,xmm3    ;*dadd {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::vectorisedDoubleSumProduct@36 (line 44)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_vectorisedDoubleSumProduct_jmhTest::vectorisedDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  6.05%    0x00000144f724f9de: add     r11d,10h          ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::vectorisedDoubleSumProduct@38 (line 43)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_vectorisedDoubleSumProduct_jmhTest::vectorisedDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  0.00%    0x00000144f724f9e2: cmp     r11d,r8d
           0x00000144f724f9e5: jl      144f724f910h      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::vectorisedDoubleSumProduct@10 (line 43)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_vectorisedDoubleSumProduct_jmhTest::vectorisedDoubleSumProduct_thrpt_jmhStub@17 (line 119)
           0x00000144f724f9eb: mov     edx,r9d
           0x00000144f724f9ee: add     edx,0fffffffdh
           0x00000144f724f9f1: cmp     r9d,edx
           0x00000144f724f9f4: mov     r9d,80000000h
           0x00000144f724f9fa: cmovl   edx,r9d
  0.00%    0x00000144f724f9fe: cmp     r11d,edx
           0x00000144f724fa01: jl      144f724f7a4h
           0x00000144f724fa07: jmp     144f724f7dfh
           0x00000144f724fa0c: vxorpd  xmm0,xmm0,xmm0
           0x00000144f724fa10: jmp     144f724f807h
           0x00000144f724fa15: mov     edx,0ffffff86h
           0x00000144f724fa1a: mov     qword ptr [rsp+70h],rcx
           0x00000144f724fa1f: push    qword ptr [rsp+80h]
           0x00000144f724fa27: pop     qword ptr [rsp+78h]
           0x00000144f724fa2c: push    qword ptr [rsp+30h]
           0x00000144f724fa31: pop     qword ptr [rsp+28h]
....................................................................................................
 99.44%  <total for region 1>

Unrolling this will disable autovectorisation, but my Skylake chip can do 8 scalar floating point operations at once.


  @Benchmark
  public double unrolledDoubleSumProduct() {
    double sp1 = 0D;
    double sp2 = 0D;
    double sp3 = 0D;
    double sp4 = 0D;
    for (int i = 0; i < xd.length && i < yd.length; i += 4) {
      sp1 += xd[i] * yd[i];
      sp2 += xd[i + 1] * yd[i + 1];
      sp3 += xd[i + 2] * yd[i + 2];
      sp4 += xd[i + 3] * yd[i + 3];
    }
    return sp1 + sp2 + sp3 + sp4;
  }

Looking at the perfasm output, you can see this code is scalar but the additions are interleaved without interdependencies. This is enough to take down a crippled target.


....[Hottest Region 1]..............................................................................
c2, com.openkappa.simd.sumproduct.generated.SumProduct_unrolledDoubleSumProduct_jmhTest::unrolledDoubleSumProduct_thrpt_jmhStub, version 162 (79 bytes) 

                                                         ;   {section_word}
           0x0000024719311ddb: lea     r9,[r12+rcx*8]
           0x0000024719311ddf: lea     rcx,[r12+rbx*8]
           0x0000024719311de3: cmp     r11d,4h
           0x0000024719311de7: jle     24719311ee1h
           0x0000024719311ded: mov     r8d,4h
           0x0000024719311df3: nop     word ptr [rax+rax+0h]
           0x0000024719311dfc: nop                       ;*iload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::unrolledDoubleSumProduct@23 (line 55)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_unrolledDoubleSumProduct_jmhTest::unrolledDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  4.20%    0x0000024719311e00: vmovsd  xmm0,qword ptr [rcx+r8*8+28h]
                                                         ;*daload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::unrolledDoubleSumProduct@116 (line 59)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_unrolledDoubleSumProduct_jmhTest::unrolledDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  8.93%    0x0000024719311e07: vmulsd  xmm0,xmm0,mmword ptr [r9+r8*8+28h]
 15.10%    0x0000024719311e0e: vmovsd  xmm1,qword ptr [rcx+r8*8+18h]
                                                         ;*daload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::unrolledDoubleSumProduct@69 (line 57)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_unrolledDoubleSumProduct_jmhTest::unrolledDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  3.95%    0x0000024719311e15: vmulsd  xmm1,xmm1,mmword ptr [r9+r8*8+18h]
  9.91%    0x0000024719311e1c: vmovsd  xmm2,qword ptr [rcx+r8*8+20h]
                                                         ;*daload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::unrolledDoubleSumProduct@92 (line 58)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_unrolledDoubleSumProduct_jmhTest::unrolledDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  3.97%    0x0000024719311e23: vmulsd  xmm2,xmm2,mmword ptr [r9+r8*8+20h]
 11.04%    0x0000024719311e2a: vmovsd  xmm3,qword ptr [rcx+r8*8+10h]
                                                         ;*daload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::unrolledDoubleSumProduct@47 (line 56)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_unrolledDoubleSumProduct_jmhTest::unrolledDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  3.86%    0x0000024719311e31: vmulsd  xmm3,xmm3,mmword ptr [r9+r8*8+10h]
  9.04%    0x0000024719311e38: vaddsd  xmm4,xmm4,xmm0    ;*dadd {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::unrolledDoubleSumProduct@118 (line 59)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_unrolledDoubleSumProduct_jmhTest::unrolledDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  7.11%    0x0000024719311e3c: vaddsd  xmm7,xmm7,xmm3    ;*dadd {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::unrolledDoubleSumProduct@49 (line 56)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_unrolledDoubleSumProduct_jmhTest::unrolledDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  7.03%    0x0000024719311e40: vaddsd  xmm5,xmm5,xmm2    ;*dadd {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::unrolledDoubleSumProduct@94 (line 58)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_unrolledDoubleSumProduct_jmhTest::unrolledDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  7.29%    0x0000024719311e44: vaddsd  xmm6,xmm6,xmm1    ;*dadd {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::unrolledDoubleSumProduct@71 (line 57)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_unrolledDoubleSumProduct_jmhTest::unrolledDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  3.58%    0x0000024719311e48: add     r8d,4h            ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::unrolledDoubleSumProduct@121 (line 55)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_unrolledDoubleSumProduct_jmhTest::unrolledDoubleSumProduct_thrpt_jmhStub@17 (line 119)
  4.39%    0x0000024719311e4c: cmp     r8d,r11d
  0.00%    0x0000024719311e4f: jl      24719311e00h      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::unrolledDoubleSumProduct@20 (line 55)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_unrolledDoubleSumProduct_jmhTest::unrolledDoubleSumProduct_thrpt_jmhStub@17 (line 119)
           0x0000024719311e51: cmp     r8d,edi
           0x0000024719311e54: jnl     24719311c92h
           0x0000024719311e5a: nop                       ;*iload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::unrolledDoubleSumProduct@23 (line 55)
                                                         ; - com.openkappa.simd.sumproduct.generated.SumProduct_unrolledDoubleSumProduct_jmhTest::unrolledDoubleSumProduct_thrpt_jmhStub@17 (line 119)
           0x0000024719311e5c: cmp     r8d,r10d
           0x0000024719311e5f: jnl     24719311f15h      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.sumproduct.SumProduct::unrolledDoubleSumProduct@30 (line 55)
....................................................................................................
 99.39%  <total for region 1>

Benchmark Mode Threads Samples Score Score Error (99.9%) Unit Param: size
unrolledDoubleSumProduct thrpt 1 10 1912.140438 48.445308 ops/ms 1024
unrolledDoubleSumProduct thrpt 1 10 24.677122 0.510459 ops/ms 65536
vectorisedDoubleSumProduct thrpt 1 10 647.848021 10.508824 ops/ms 1024
vectorisedDoubleSumProduct thrpt 1 10 9.474097 0.479281 ops/ms 65536

So, if you realise that in your application the order of your array is irrelevant, you can write a tiny bit of extra code and get multiplicatively better performance. These results were produced with JDK9. When I tried with JDK10, the sum product was not vectorised, presumably because it has been noticed that it is unprofitable. This benchmark can be seen in full context at github.

Vertical Sum

I was motivated to write this post after Ioannis Tsakpinis shared a gist of a benchmark after reading a recent post about coaxing vectorisation into action for a simple floating point sum. The post was intended to be a prelude to a post about the wonders of paginated arrays. With a paginated array, autovectorisation pays off and is preferable to a manual unroll. The non-associativity of the operation is of course still violated, but I am working on the premise that this virtually never matters. I revisited this benchmark, with a paginated array this time.


  @Benchmark // inspired by Ioannis' code
  public double reduceUnrolledPaginated() {
    double a0 = 0.0;
    double a1 = 0.0;
    double a2 = 0.0;
    double a3 = 0.0;
    for (int i = 0; i < paginated.length; ++i) {
      double[] page = paginated[i];
      for (int j = 0; j < paginated[0].length; j += 4) {
        a0 += page[j + 0];
        a1 += page[j + 1];
        a2 += page[j + 2];
        a3 += page[j + 3];
      }
    }
    return a0 + a1 + a2 + a3;
  }

  @Benchmark
  public double reducePaginated() {
    double[] buffer = Arrays.copyOf(paginated[0], paginated[0].length);
    for (int i = 1; i < paginated.length; ++i) {
      double[] page = paginated[i];
      for (int j = 0; j < page.length && j < buffer.length; ++j) {
        buffer[j] += page[j];
      }
    }
    return reduceUnrolled(buffer);
  }

The array being paginated, requiring no offset calculations, is the perfect case for a vectorised loop here. Which is one reason why Java arrays should be paginated in application code.

Benchmark Mode Threads Samples Score Score Error (99.9%) Unit Param: size
reducePaginated thrpt 1 10 597.046492 23.080803 ops/ms 1024
reducePaginated thrpt 1 10 42.801021 0.831318 ops/ms 65536
reducePaginated thrpt 1 10 1.503510 0.187167 ops/ms 1048576
reduceUnrolledPaginated thrpt 1 10 1311.433592 9.063721 ops/ms 1024
reduceUnrolledPaginated thrpt 1 10 19.448202 0.503753 ops/ms 65536
reduceUnrolledPaginated thrpt 1 10 1.052183 0.086555 ops/ms 1048576

Nevertheless, loop unrolling can be a significant boon for floating point arithmetic in Java. It feels dirty to me – it’s one of those things that people did before my time. Compilers know how to do it, if they are allowed to do so. If there is no place for fastfp in Java, I imagine they are here to stay.

Posted on

Iterating Over a Bitset in Java

How fast can you iterate over a bitset? Daniel Lemire published a benchmark recently in support of a strategy using the number of trailing zeroes to skip over empty bits. I have used the same technique in Java several times in my hobby project SplitMap and this is something I am keen to optimise. I think that the best strategy depends on what you want to do with the set bits, and how sparse and uniformly distributed they are. I argue that the cost of iteration is less important than the constraints your API imposes on the caller, and whether the caller is free to exploit patterns in the data.

C2 Generates Good Code

If you think C++ is much faster than Java, you either don’t know much about Java or do lots of floating point arithmetic. This isn’t about benchmarking C++ against Java, but comparing the compilation outputs for a C++ implementation and a Java implementation shows that there won’t be much difference if your Java method gets hot. Only the time to performance will differ, and this is amortised over the lifetime of an application. The trailing zeroes implementation is probably the fastest technique in Java as well as in C++, but that is to ignore the optimisations you can’t apply to the callback if you use it too literally.

Compiling this C++ function with GCC yields the snippet of assembly taken from the loop kernel:


template <typename CALLBACK>
static void for_each(const long* bitmap, const int size, const CALLBACK& callback) {
    for (size_t k = 0; k < size; ++k) {
        long bitset = bitmap[k];
        while (bitset != 0) {
            callback((k * 64) + __builtin_ctzl(bitset));
            bitset ^= (bitset & -bitset);
        }
    }
}

The instruction tzcntl calculates the next set bit and blsr switches it off.


.L99:
  movq  %rdi, %rcx
  blsr  %ebx, %ebx
  call  _ZNSo3putEc
  movq  %rax, %rcx
  call  _ZNSo5flushEv
  testl  %ebx, %ebx
  je  .L96
.L100:
  xorl  %edx, %edx
  movq  %r12, %rcx
  tzcntl  %ebx, %edx
  addl  %ebp, %edx
  call  _ZNSolsEi
  movq  %rax, %rdi
  movq  (%rax), %rax
  movq  -24(%rax), %rax
  movq  240(%rdi,%rax), %rsi
  testq  %rsi, %rsi
  je  .L108
  cmpb  $0, 56(%rsi)
  jne  .L109
  movq  %rsi, %rcx
  call  _ZNKSt5ctypeIcE13_M_widen_initEv
  movq  (%rsi), %rax
  movl  $10, %edx
  movq  48(%rax), %rax
  cmpq  %r14, %rax
  je  .L99
  movq  %rsi, %rcx
  call  *%rax
  movsbl  %al, %edx
  jmp  .L99
  .p2align 4,,10

In Java, almost identical code is generated.


public void forEach(long[] bitmap, IntConsumer consumer) {
    for (int i = 0; i < bitmap.length; ++i) {
      long word = bitmap[i];
      while (word != 0) {
        consumer.accept(Long.SIZE * i + Long.numberOfTrailingZeros(word));
        word ^= Long.lowestOneBit(word);
      }
    }
  }

The key difference is that xor and blsi haven’t been fused into blsr, so the C++ code is probably slightly faster. A lambda function accumulating the contents of an array is inlined into this loop (the add comes from an inlined lambda, but notice how little time is spent adding compared to computing the bit to switch off in this sample produced by perfasm).


   .83%    0x000002d79d366a19: tzcnt   r9,rcx
  8.53%    0x000002d79d366a1e: add     r9d,ebx
  0.42%    0x000002d79d366a21: cmp     r9d,r8d
  0.00%    0x000002d79d366a24: jnb     2d79d366a4dh
  0.62%    0x000002d79d366a26: add     r10d,dword ptr [rdi+r9*4+10h]
 16.22%    0x000002d79d366a2b: vmovq   r11,xmm4
  6.68%    0x000002d79d366a30: mov     dword ptr [r11+10h],r10d
 27.92%    0x000002d79d366a34: blsi    r10,rcx
  0.55%    0x000002d79d366a39: xor     rcx,r10         
  0.10%    0x000002d79d366a3c: mov     r11,qword ptr [r15+70h]  

It’s this Java code, and its impact on which optimisations can be applied to the IntConsumer that this post focuses on. There are different principles, particularly related to inlining and vectorisation opportunities in C++, but this blog is about Java. Depending on what your callback does, you get different benchmark results and you should make different choices about how to do the iteration: you just can’t assess this in isolation.

Special Casing -1

Imagine you have an int[] containing data, and you are iterating over a mask or materialised predicate over that data. For each set bit, you want to add the corresponding entry in the array to a sum. In Java, that looks like this (you’ve already seen the generated assembly above):


  @Benchmark
  public int reduce() {
    int[] result = new int[1];
    forEach(bitmap, i -> result[0] += data[i]);
    return result[0];
  }

How fast can this get? It obviously depends on how full the bitset is. The worst case would be that it’s completely full, and it couldn’t get much better than if only one bit per word were set. The difference is noticeable, but scales by a factor less than the number of bits:

Benchmark Mode Threads Samples Score Score Error (99.9%) Unit Param: scenario
reduce thrpt 1 10 7.435909 0.017491 ops/ms FULL
reduce thrpt 1 10 260.305307 6.081961 ops/ms ONE_BIT_PER_WORD

But the important code here, the callback itself, is stuck at entry level compilation. There is no unrolling, no vectorisation, the adds can’t be pipelined because there is a data dependency on blsi and xor. We can do much better in some cases, and not much worse in others, just by treating -1 as a special case, profiting from optimisations that can now be applied inside the callback. Passing a different callback which consumes whole words costs a branch, but it’s often worth it. Here’s the iterator now:


  interface WordConsumer {
    void acceptWord(int wordIndex, long word);
  }

  public void forEach(long[] bitmap, IntConsumer intConsumer, WordConsumer wordConsumer) {
    for (int i = 0; i < bitmap.length; ++i) {
      long word = bitmap[i];
      if (word == -1L) {
        wordConsumer.acceptWord(i, word);
      } else {
        while (word != 0) {
          intConsumer.accept(Long.SIZE * i + Long.numberOfTrailingZeros(word));
          word ^= Long.lowestOneBit(word);
        }
      }
    }
  }

  @Benchmark
  public int reduceWithWordConsumer() {
    int[] result = new int[1];
    forEach(bitmap, i -> result[0] += data[i], (index, word) -> {
      if (word != -1L) {
        throw new IllegalStateException();
      }
      int sum = 0;
      for (int i = index * Long.SIZE; i < (index + 1) * Long.SIZE; ++i) {
        sum += data[i];
      }
      result[0] += sum;
    });
    return result[0];
  }

This really pays off when the bitset is full, but having that extra branch does seem to cost something even though it is never taken, whereas the full case improves 6x.

Benchmark Mode Threads Samples Score Score Error (99.9%) Unit Param: scenario
reduce thrpt 1 10 7.401202 0.118648 ops/ms FULL
reduce thrpt 1 10 261.682016 4.155856 ops/ms ONE_BIT_PER_WORD
reduceWithWordConsumer thrpt 1 10 43.972759 0.993264 ops/ms FULL
reduceWithWordConsumer thrpt 1 10 222.824868 4.877147 ops/ms ONE_BIT_PER_WORD

We still don’t actually know the cost of the branch when it’s taken every now and then. To estimate it, we need a new scenario (or new scenarios) which mix full and sparse words. As you might expect, having the WordConsumer is great when one word in every few is full: the fast path is so much faster, it practically skips the word.

Benchmark Mode Threads Samples Score Score Error (99.9%) Unit Param: scenario
reduce thrpt 1 10 157.358633 4.538679 ops/ms SPARSE_16_FULL_WORDS
reduceWithWordConsumer thrpt 1 10 257.041035 7.446404 ops/ms SPARSE_16_FULL_WORDS

So in this scenario, the branch has paid for itself. How? The data dependency has been removed with a countable loop. Here’s the perfasm output. Notice two things: long runs of add instructions, and the vastly reduced percentage against blsi. The time is now spent adding numbers up, not switching off least significant bits. This feels like progress.


....[Hottest Region 1]..............................................................................
c2, com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub, version 170 (804 bytes) 

                                                         ;   {optimized virtual_call}
           0x000001dd5b35acd4: mov     r9,qword ptr [rsp+0a0h]
           0x000001dd5b35acdc: movzx   r11d,byte ptr [r9+94h]  ;*getfield isDone {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@30 (line 144)
                                                         ; implicit exception: dispatches to 0x000001dd5b35b486
           0x000001dd5b35ace4: test    r11d,r11d
           0x000001dd5b35ace7: jne     1dd5b35b19dh      ;*ifeq {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@33 (line 144)
           0x000001dd5b35aced: mov     ebx,1h
           0x000001dd5b35acf2: jmp     1dd5b35ad31h
  0.00%    0x000001dd5b35acf4: vmovq   rdi,xmm0          ;*invokevirtual reduceWithWordConsumer {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001dd5b35acf9: mov     r8d,dword ptr [rdi+10h]  ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@28 (line 85)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001dd5b35acfd: mov     rdx,qword ptr [rsp+30h]
  0.03%    0x000001dd5b35ad02: nop
  0.00%    0x000001dd5b35ad03: call    1dd5b2c7000h      ; ImmutableOopMap{[160]=Oop [168]=Oop [176]=Oop [40]=NarrowOop [48]=Oop }
                                                         ;*invokevirtual consume {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@20 (line 142)
                                                         ;   {optimized virtual_call}
  0.04%    0x000001dd5b35ad08: mov     r9,qword ptr [rsp+0a0h]
           0x000001dd5b35ad10: movzx   r11d,byte ptr [r9+94h]  ;*putfield arg$1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::&lt;init&gt;@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::get$Lambda@6
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/592450429::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@11 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.02%    0x000001dd5b35ad18: mov     r10,qword ptr [r15+70h]
  0.00%    0x000001dd5b35ad1c: mov     rbx,qword ptr [rsp+40h]
  0.03%    0x000001dd5b35ad21: add     rbx,1h            ; ImmutableOopMap{r9=Oop [160]=Oop [168]=Oop [176]=Oop [40]=NarrowOop [48]=Oop }
                                                         ;*ifeq {reexecute=1 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@33 (line 144)
  0.00%    0x000001dd5b35ad25: test    dword ptr [r10],eax  ;   {poll}
  0.00%    0x000001dd5b35ad28: test    r11d,r11d
           0x000001dd5b35ad2b: jne     1dd5b35b1a2h
  0.00%    0x000001dd5b35ad31: mov     rdi,qword ptr [r15+80h]
  0.01%    0x000001dd5b35ad38: mov     r10,rdi
  0.00%    0x000001dd5b35ad3b: add     r10,18h
  0.01%    0x000001dd5b35ad3f: cmp     r10,qword ptr [r15+90h]
           0x000001dd5b35ad46: jnb     1dd5b35b119h      ;*putfield arg$1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::&lt;init&gt;@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::get$Lambda@6
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/592450429::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@11 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001dd5b35ad4c: mov     qword ptr [r15+80h],r10
           0x000001dd5b35ad53: prefetchw byte ptr [r10+0c0h]
  0.00%    0x000001dd5b35ad5b: mov     qword ptr [rdi],1h
  0.01%    0x000001dd5b35ad62: prefetchw byte ptr [r10+100h]
           0x000001dd5b35ad6a: mov     dword ptr [rdi+8h],0f8000168h
                                                         ;   {metadata({type array int})}
  0.00%    0x000001dd5b35ad71: prefetchw byte ptr [r10+140h]
  0.01%    0x000001dd5b35ad79: mov     dword ptr [rdi+0ch],1h
  0.01%    0x000001dd5b35ad80: prefetchw byte ptr [r10+180h]
  0.00%    0x000001dd5b35ad88: mov     qword ptr [rdi+10h],r12  ;*newarray {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@1 (line 74)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001dd5b35ad8c: mov     rcx,qword ptr [rsp+0b0h]
  0.00%    0x000001dd5b35ad94: mov     ebp,dword ptr [rcx+0ch]  ;*getfield bitmap {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@6 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001dd5b35ad97: mov     dword ptr [rsp+70h],ebp
  0.00%    0x000001dd5b35ad9b: mov     rsi,qword ptr [r15+80h]
  0.00%    0x000001dd5b35ada2: mov     r10,rsi
           0x000001dd5b35ada5: add     r10,18h
  0.00%    0x000001dd5b35ada9: cmp     r10,qword ptr [r15+90h]
           0x000001dd5b35adb0: jnb     1dd5b35b14fh      ;*putfield arg$1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::&lt;init&gt;@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::get$Lambda@6
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/592450429::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@11 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001dd5b35adb6: mov     qword ptr [r15+80h],r10
           0x000001dd5b35adbd: prefetchw byte ptr [r10+0c0h]
  0.00%    0x000001dd5b35adc5: mov     r8,qword ptr [rsp+20h]
  0.01%    0x000001dd5b35adca: mov     r10,qword ptr [r8+0b0h]
  0.01%    0x000001dd5b35add1: mov     qword ptr [rsi],r10
  0.00%    0x000001dd5b35add4: mov     dword ptr [rsi+8h],0f8021906h
                                                         ;   {metadata(&apos;com/openkappa/simd/iterate/BitSetIterator$$Lambda$43&apos;)}
           0x000001dd5b35addb: mov     qword ptr [rsi+10h],r12  ;*new {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::get$Lambda@0
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/592450429::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@11 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001dd5b35addf: mov     r11d,dword ptr [rsp+28h]
  0.00%    0x000001dd5b35ade4: mov     dword ptr [rsi+0ch],r11d
                                                         ;*putfield arg$1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::&lt;init&gt;@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::get$Lambda@6
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/592450429::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@11 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001dd5b35ade8: mov     rax,qword ptr [r15+80h]
  0.00%    0x000001dd5b35adef: mov     rbp,rdi
  0.01%    0x000001dd5b35adf2: shr     rbp,3h
  0.00%    0x000001dd5b35adf6: mov     dword ptr [rsi+10h],ebp  ;*putfield arg$2 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::&lt;init&gt;@11
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::get$Lambda@6
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/592450429::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@11 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001dd5b35adf9: mov     r10,rax
  0.00%    0x000001dd5b35adfc: add     r10,18h
  0.00%    0x000001dd5b35ae00: cmp     r10,qword ptr [r15+90h]
           0x000001dd5b35ae07: jnb     1dd5b35b08eh      ;*putfield arg$1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::&lt;init&gt;@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::get$Lambda@6
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/592450429::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@11 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001dd5b35ae0d: mov     qword ptr [r15+80h],r10
  0.00%    0x000001dd5b35ae14: prefetchw byte ptr [r10+0c0h]
  0.00%    0x000001dd5b35ae1c: mov     rdx,qword ptr [rsp+38h]
  0.00%    0x000001dd5b35ae21: mov     r10,qword ptr [rdx+0b0h]
  0.02%    0x000001dd5b35ae28: mov     qword ptr [rax],r10
  0.01%    0x000001dd5b35ae2b: mov     dword ptr [rax+8h],0f8021a86h
                                                         ;   {metadata(&apos;com/openkappa/simd/iterate/BitSetIterator$$Lambda$44&apos;)}
  0.00%    0x000001dd5b35ae32: mov     qword ptr [rax+10h],r12
  0.00%    0x000001dd5b35ae36: mov     dword ptr [rax+0ch],r11d
                                                         ;*new {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::get$Lambda@0
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/592450429::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@18 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001dd5b35ae3a: mov     dword ptr [rax+10h],ebp  ;*invokespecial &lt;init&gt; {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::get$Lambda@6
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/592450429::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@18 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001dd5b35ae3d: mov     ebp,dword ptr [rsp+70h]
  0.00%    0x000001dd5b35ae41: mov     r13d,dword ptr [r12+rbp*8+0ch]
                                                         ;*arraylength {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@6 (line 104)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
                                                         ; implicit exception: dispatches to 0x000001dd5b35b422
  0.03%    0x000001dd5b35ae46: test    r13d,r13d
           0x000001dd5b35ae49: jbe     1dd5b35b024h      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@7 (line 104)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001dd5b35ae4f: mov     r10d,r13d
  0.00%    0x000001dd5b35ae52: dec     r10d
           0x000001dd5b35ae55: cmp     r10d,r13d
           0x000001dd5b35ae58: jnb     1dd5b35b24ah
  0.01%    0x000001dd5b35ae5e: lea     r14,[r12+rbp*8]   ;*getfield bitmap {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@6 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001dd5b35ae62: xor     r10d,r10d
  0.00%    0x000001dd5b35ae65: xor     ebp,ebp
           0x000001dd5b35ae67: mov     qword ptr [rsp+0b0h],rcx
  0.00%    0x000001dd5b35ae6f: mov     qword ptr [rsp+0a0h],r9
           0x000001dd5b35ae77: mov     qword ptr [rsp+20h],r8
  0.01%    0x000001dd5b35ae7c: mov     dword ptr [rsp+28h],r11d
  0.00%    0x000001dd5b35ae81: mov     qword ptr [rsp+38h],rdx
  0.00%    0x000001dd5b35ae86: mov     qword ptr [rsp+40h],rbx
  0.00%    0x000001dd5b35ae8b: vmovq   xmm0,rdi
  0.00%    0x000001dd5b35ae90: jmp     1dd5b35afafh
  0.03%    0x000001dd5b35ae95: mov     r8d,r10d
  0.03%    0x000001dd5b35ae98: add     r8d,40h           ;*imul {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@32 (line 80)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.04%    0x000001dd5b35ae9c: cmp     r10d,r8d
           0x000001dd5b35ae9f: jnl     1dd5b35b01dh      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@33 (line 80)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.03%    0x000001dd5b35aea5: mov     r11d,dword ptr [r12+rcx*8+0ch]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@44 (line 81)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
                                                         ; implicit exception: dispatches to 0x000001dd5b35b1d3
  0.04%    0x000001dd5b35aeaa: cmp     r10d,r11d
           0x000001dd5b35aead: jnb     1dd5b35b1d3h
  0.04%    0x000001dd5b35aeb3: movsxd  r11,r11d
  0.04%    0x000001dd5b35aeb6: movsxd  r9,r8d
  0.02%    0x000001dd5b35aeb9: dec     r9
  0.05%    0x000001dd5b35aebc: cmp     r9,r11
  0.00%    0x000001dd5b35aebf: jnb     1dd5b35b1d3h
  0.04%    0x000001dd5b35aec5: lea     rdi,[r12+rcx*8]
  0.04%    0x000001dd5b35aec9: mov     ecx,r10d
  0.03%    0x000001dd5b35aecc: inc     ecx
  0.04%    0x000001dd5b35aece: mov     r9d,r10d
  0.04%    0x000001dd5b35aed1: xor     ebx,ebx           ;*iload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@36 (line 81)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.03%    0x000001dd5b35aed3: add     ebx,dword ptr [rdi+r9*4+10h]
                                                         ;*iadd {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@45 (line 81)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.20%    0x000001dd5b35aed8: inc     r9d               ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@48 (line 80)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.04%    0x000001dd5b35aedb: cmp     r9d,ecx
           0x000001dd5b35aede: jl      1dd5b35aed3h      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@33 (line 80)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.04%    0x000001dd5b35aee0: add     r10d,31h
  0.03%    0x000001dd5b35aee4: cmp     r8d,r10d
  0.03%    0x000001dd5b35aee7: mov     r11d,80000000h
  0.04%    0x000001dd5b35aeed: cmovl   r10d,r11d
  0.04%    0x000001dd5b35aef1: cmp     r9d,r10d
           0x000001dd5b35aef4: jnl     1dd5b35af68h
  0.04%    0x000001dd5b35aef6: nop     word ptr [rax+rax+0h]  ;*iload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@36 (line 81)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.07%    0x000001dd5b35af00: movsxd  r11,r9d
  0.05%    0x000001dd5b35af03: add     ebx,dword ptr [rdi+r9*4+10h]
  0.31%    0x000001dd5b35af08: add     ebx,dword ptr [rdi+r11*4+14h]
  0.32%    0x000001dd5b35af0d: add     ebx,dword ptr [rdi+r11*4+18h]
  0.33%    0x000001dd5b35af12: add     ebx,dword ptr [rdi+r11*4+1ch]
  0.37%    0x000001dd5b35af17: add     ebx,dword ptr [rdi+r11*4+20h]
  0.34%    0x000001dd5b35af1c: add     ebx,dword ptr [rdi+r11*4+24h]
  0.39%    0x000001dd5b35af21: add     ebx,dword ptr [rdi+r11*4+28h]
  0.36%    0x000001dd5b35af26: add     ebx,dword ptr [rdi+r11*4+2ch]
  0.34%    0x000001dd5b35af2b: add     ebx,dword ptr [rdi+r11*4+30h]
  0.35%    0x000001dd5b35af30: add     ebx,dword ptr [rdi+r11*4+34h]
  0.38%    0x000001dd5b35af35: add     ebx,dword ptr [rdi+r11*4+38h]
  0.36%    0x000001dd5b35af3a: add     ebx,dword ptr [rdi+r11*4+3ch]
  0.49%    0x000001dd5b35af3f: add     ebx,dword ptr [rdi+r11*4+40h]
  0.39%    0x000001dd5b35af44: add     ebx,dword ptr [rdi+r11*4+44h]
  0.42%    0x000001dd5b35af49: add     ebx,dword ptr [rdi+r11*4+48h]
  0.39%    0x000001dd5b35af4e: add     ebx,dword ptr [rdi+r11*4+4ch]
                                                         ;*iadd {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@45 (line 81)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.41%    0x000001dd5b35af53: add     r9d,10h           ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@48 (line 80)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001dd5b35af57: cmp     r9d,r10d
           0x000001dd5b35af5a: jl      1dd5b35af00h      ;*putfield arg$1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::&lt;init&gt;@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::get$Lambda@6
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/592450429::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@11 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
           0x000001dd5b35af5c: mov     r11,qword ptr [r15+70h]  ; ImmutableOopMap{rdi=Oop rsi=Oop rax=Oop r14=Oop xmm0=Oop [160]=Oop [168]=Oop [176]=Oop [40]=NarrowOop [48]=Oop [112]=NarrowOop }
                                                         ;*goto {reexecute=1 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@51 (line 80)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
           0x000001dd5b35af60: test    dword ptr [r11],eax  ;*goto {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@51 (line 80)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
                                                         ;   {poll}
  0.15%    0x000001dd5b35af63: cmp     r9d,r10d
           0x000001dd5b35af66: jl      1dd5b35af00h
           0x000001dd5b35af68: cmp     r9d,r8d
           0x000001dd5b35af6b: jnl     1dd5b35af7dh
           0x000001dd5b35af6d: nop                       ;*iload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@36 (line 81)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.67%    0x000001dd5b35af70: add     ebx,dword ptr [rdi+r9*4+10h]
                                                         ;*iadd {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@45 (line 81)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  1.59%    0x000001dd5b35af75: inc     r9d               ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@48 (line 80)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.13%    0x000001dd5b35af78: cmp     r9d,r8d
           0x000001dd5b35af7b: jl      1dd5b35af70h      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@33 (line 80)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
           0x000001dd5b35af7d: vmovq   r10,xmm0
  0.02%    0x000001dd5b35af82: add     dword ptr [r10+10h],ebx
  2.64%    0x000001dd5b35af86: mov     r8,rax
  2.45%    0x000001dd5b35af89: mov     r9,rsi            ;*putfield arg$1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::&lt;init&gt;@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::get$Lambda@6
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/592450429::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@11 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.70%    0x000001dd5b35af8c: mov     r10,qword ptr [r15+70h]
  2.16%    0x000001dd5b35af90: mov     r11d,ebp
  2.37%    0x000001dd5b35af93: inc     r11d              ; ImmutableOopMap{r8=Oop r9=Oop rsi=Oop rax=Oop r14=Oop xmm0=Oop [160]=Oop [168]=Oop [176]=Oop [40]=NarrowOop [48]=Oop [112]=NarrowOop }
                                                         ;*goto {reexecute=1 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@78 (line 104)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.44%    0x000001dd5b35af96: test    dword ptr [r10],eax  ;*goto {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@78 (line 104)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
                                                         ;   {poll}
  2.74%    0x000001dd5b35af99: cmp     r11d,r13d
  0.00%    0x000001dd5b35af9c: jnl     1dd5b35acf4h      ;*aload_1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@10 (line 105)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.14%    0x000001dd5b35afa2: shl     ebp,6h
  2.37%    0x000001dd5b35afa5: mov     r10d,ebp
  2.41%    0x000001dd5b35afa8: add     r10d,40h          ;*imul {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$2@22 (line 80)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/778368703::acceptWord@10
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 107)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.72%    0x000001dd5b35afac: mov     ebp,r11d          ;*aload_1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@10 (line 105)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.14%    0x000001dd5b35afaf: mov     rbx,qword ptr [r14+rbp*8+10h]
                                                         ;*laload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@13 (line 105)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.59%    0x000001dd5b35afb4: mov     r11,qword ptr [rsp+0b0h]
  2.30%    0x000001dd5b35afbc: mov     ecx,dword ptr [r11+10h]  ;*getfield data {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$1@5 (line 75)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::accept@9
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@57 (line 110)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.76%    0x000001dd5b35afc0: cmp     rbx,0ffffffffffffffffh
           0x000001dd5b35afc4: je      1dd5b35ae95h      ;*ifne {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@22 (line 106)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.09%    0x000001dd5b35afca: test    rbx,rbx
  0.00%    0x000001dd5b35afcd: je      1dd5b35af86h      ;*ifeq {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@42 (line 109)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.34%    0x000001dd5b35afcf: mov     r9d,dword ptr [r12+rcx*8+0ch]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$1@9 (line 75)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::accept@9
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@57 (line 110)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
                                                         ; implicit exception: dispatches to 0x000001dd5b35b3f6
  2.50%    0x000001dd5b35afd4: lea     rdi,[r12+rcx*8]
  2.62%    0x000001dd5b35afd8: nop     dword ptr [rax+rax+0h]  ;*aload_2 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@45 (line 110)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.11%    0x000001dd5b35afe0: vmovq   r11,xmm0
  2.35%    0x000001dd5b35afe5: mov     r8d,dword ptr [r11+10h]  ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduceWithWordConsumer$1@3 (line 75)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::accept@9
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@57 (line 110)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.39%    0x000001dd5b35afe9: tzcnt   r11,rbx
  2.65%    0x000001dd5b35afee: add     r11d,r10d         ;*iadd {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@56 (line 110)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.15%    0x000001dd5b35aff1: cmp     r11d,r9d
  0.00%    0x000001dd5b35aff4: jnb     1dd5b35b04dh
  2.29%    0x000001dd5b35aff6: add     r8d,dword ptr [rdi+r11*4+10h]
 11.03%    0x000001dd5b35affb: vmovq   r11,xmm0
  2.45%    0x000001dd5b35b000: mov     dword ptr [r11+10h],r8d  ;*putfield arg$1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::&lt;init&gt;@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/513487367::get$Lambda@6
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/592450429::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@11 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  3.14%    0x000001dd5b35b004: mov     r11,qword ptr [r15+70h]
  2.18%    0x000001dd5b35b008: blsi    r8,rbx
  2.23%    0x000001dd5b35b00d: xor     rbx,r8            ; ImmutableOopMap{rcx=NarrowOop rdi=Oop rsi=Oop rax=Oop r14=Oop xmm0=Oop [160]=Oop [168]=Oop [176]=Oop [40]=NarrowOop [48]=Oop [112]=NarrowOop }
                                                         ;*goto {reexecute=1 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@72 (line 111)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.44%    0x000001dd5b35b010: test    dword ptr [r11],eax  ;*goto {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@72 (line 111)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
                                                         ;   {poll}
  2.71%    0x000001dd5b35b013: test    rbx,rbx
           0x000001dd5b35b016: jne     1dd5b35afe0h      ;*ifeq {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@42 (line 109)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduceWithWordConsumer@23 (line 75)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduceWithWordConsumer_jmhTest::reduceWithWordConsumer_thrpt_jmhStub@17 (line 142)
  2.23%    0x000001dd5b35b018: jmp     1dd5b35af86h
           0x000001dd5b35b01d: xor     ebx,ebx
           0x000001dd5b35b01f: jmp     1dd5b35af7dh
           0x000001dd5b35b024: mov     qword ptr [rsp+0b0h],rcx
           0x000001dd5b35b02c: mov     qword ptr [rsp+0a0h],r9
           0x000001dd5b35b034: mov     qword ptr [rsp+20h],r8
           0x000001dd5b35b039: mov     dword ptr [rsp+28h],r11d
           0x000001dd5b35b03e: mov     qword ptr [rsp+38h],rdx
....................................................................................................
 98.92%  <total for region 1>

Heroically ploughing through the full words tells a different story: blsi is up at 11%. This indicates more time is spent iterating rather than evaluating the callback.


....[Hottest Region 1]..............................................................................
c2, com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub, version 164 (218 bytes) 

                                                         ; - java.lang.invoke.LambdaForm$MH/1035918105::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@11 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
           0x0000019f106c66e7: mov     qword ptr [r15+3d8h],rdi
                                                         ;*invokespecial &lt;init&gt; {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/1830914914::get$Lambda@6
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/1035918105::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@11 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  0.00%    0x0000019f106c66ee: mov     r10d,dword ptr [rsp+60h]
  0.00%    0x0000019f106c66f3: mov     edx,dword ptr [r12+r10*8+0ch]
                                                         ;*arraylength {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@4 (line 89)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
                                                         ; implicit exception: dispatches to 0x0000019f106c6aba
  0.02%    0x0000019f106c66f8: test    edx,edx
           0x0000019f106c66fa: jbe     19f106c6826h      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@5 (line 89)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
           0x0000019f106c6700: mov     r10d,edx
  0.00%    0x0000019f106c6703: dec     r10d
           0x0000019f106c6706: cmp     r10d,edx
           0x0000019f106c6709: jnb     19f106c6942h
  0.00%    0x0000019f106c670f: mov     r10d,dword ptr [rsp+60h]
           0x0000019f106c6714: lea     rax,[r12+r10*8]   ;*getfield bitmap {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@6 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  0.00%    0x0000019f106c6718: xor     ecx,ecx
           0x0000019f106c671a: jmp     19f106c674dh
  1.54%    0x0000019f106c671c: mov     r11,r13
  1.57%    0x0000019f106c671f: mov     r13,rbp
  1.69%    0x0000019f106c6722: mov     r8,r14
  1.46%    0x0000019f106c6725: vmovd   r9d,xmm1
  1.48%    0x0000019f106c672a: vmovq   rbx,xmm0
  1.61%    0x0000019f106c672f: vmovq   r14,xmm2
  1.63%    0x0000019f106c6734: vmovq   rbp,xmm3
  1.46%    0x0000019f106c6739: mov     rdi,rbp           ;*putfield arg$1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/1830914914::&lt;init&gt;@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/1830914914::get$Lambda@6
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/1035918105::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@11 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  1.49%    0x0000019f106c673c: mov     r10,qword ptr [r15+70h]
  1.54%    0x0000019f106c6740: inc     ecx               ; ImmutableOopMap{r11=Oop r9=NarrowOop rdi=Oop rax=Oop rbp=Oop r13=Oop r14=Oop [152]=Oop [48]=Oop [96]=NarrowOop }
                                                         ;*goto {reexecute=1 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@52 (line 89)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  1.73%    0x0000019f106c6742: test    dword ptr [r10],eax  ;*goto {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@52 (line 89)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
                                                         ;   {poll}
  1.43%    0x0000019f106c6745: cmp     ecx,edx
  0.00%    0x0000019f106c6747: jnl     19f106c6480h      ;*aload_1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@8 (line 90)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  1.57%    0x0000019f106c674d: mov     rdi,qword ptr [rax+rcx*8+10h]
                                                         ;*laload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@10 (line 90)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  1.61%    0x0000019f106c6752: test    rdi,rdi
           0x0000019f106c6755: je      19f106c6739h      ;*ifeq {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@17 (line 91)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  1.68%    0x0000019f106c6757: vmovq   xmm3,rbp
  1.47%    0x0000019f106c675c: mov     esi,dword ptr [r11+10h]  ;*getfield data {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduce$0@5 (line 67)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/1830914914::accept@9
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@31 (line 92)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  1.48%    0x0000019f106c6760: mov     r10d,dword ptr [r12+rsi*8+0ch]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduce$0@9 (line 67)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/1830914914::accept@9
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@31 (line 92)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
                                                         ; implicit exception: dispatches to 0x0000019f106c6a3e
  1.58%    0x0000019f106c6765: vmovq   xmm2,r14
  1.68%    0x0000019f106c676a: vmovq   xmm0,rbx
  1.46%    0x0000019f106c676f: vmovd   xmm1,r9d
  1.46%    0x0000019f106c6774: mov     r14,r8
  1.51%    0x0000019f106c6777: mov     rbp,r13
  1.68%    0x0000019f106c677a: mov     r13,r11
  1.41%    0x0000019f106c677d: lea     r8,[r12+rsi*8]
  1.40%    0x0000019f106c6781: mov     ebx,ecx
  1.55%    0x0000019f106c6783: shl     ebx,6h
  1.63%    0x0000019f106c6786: nop     word ptr [rax+rax+0h]  ;*aload_2 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@20 (line 92)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  1.68%    0x0000019f106c6790: vmovq   r11,xmm2
  1.70%    0x0000019f106c6795: mov     r11d,dword ptr [r11+10h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$reduce$0@3 (line 67)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/1830914914::accept@9
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@31 (line 92)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  6.98%    0x0000019f106c6799: tzcnt   r9,rdi
  3.47%    0x0000019f106c679e: add     r9d,ebx           ;*iadd {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 92)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  1.65%    0x0000019f106c67a1: cmp     r9d,r10d
           0x0000019f106c67a4: jnb     19f106c67cdh
  1.67%    0x0000019f106c67a6: add     r11d,dword ptr [r8+r9*4+10h]
 11.45%    0x0000019f106c67ab: vmovq   r9,xmm2
  3.20%    0x0000019f106c67b0: mov     dword ptr [r9+10h],r11d  ;*goto {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@46 (line 93)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
 11.31%    0x0000019f106c67b4: blsi    r11,rdi
  1.71%    0x0000019f106c67b9: xor     rdi,r11           ;*putfield arg$1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/1830914914::&lt;init&gt;@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/1830914914::get$Lambda@6
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@11
                                                         ; - java.lang.invoke.LambdaForm$MH/1035918105::linkToTargetMethod@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@11 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  1.72%    0x0000019f106c67bc: mov     r11,qword ptr [r15+70h]  ; ImmutableOopMap{r8=Oop r9=Oop rsi=NarrowOop rax=Oop rbp=Oop r13=Oop xmm1=NarrowOop xmm2=Oop xmm3=Oop [152]=Oop [48]=Oop [96]=NarrowOop }
                                                         ;*goto {reexecute=1 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@46 (line 93)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  1.80%    0x0000019f106c67c0: test    dword ptr [r11],eax  ;*goto {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@46 (line 93)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
                                                         ;   {poll}
  6.99%    0x0000019f106c67c3: test    rdi,rdi
           0x0000019f106c67c6: jne     19f106c6790h      ;*ifeq {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@17 (line 91)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::reduce@16 (line 67)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_reduce_jmhTest::reduce_thrpt_jmhStub@17 (line 142)
  1.39%    0x0000019f106c67c8: jmp     19f106c671ch
           0x0000019f106c67cd: mov     edx,0ffffffe4h
           0x0000019f106c67d2: mov     r10,qword ptr [rsp+98h]
           0x0000019f106c67da: mov     qword ptr [rsp+90h],r10
           0x0000019f106c67e2: mov     r10,qword ptr [rsp+30h]
           0x0000019f106c67e7: mov     qword ptr [rsp+0a0h],r13
           0x0000019f106c67ef: vmovsd  qword ptr [rsp+20h],xmm0
           0x0000019f106c67f5: mov     qword ptr [rsp+28h],r10
....................................................................................................
 98.59%  <total for region 1>

This shows the cost of a data dependency in a loop. The operation we want to perform is associative, so we could even vectorise this. In C++ that might happen automatically, or could be ensured with intrinsics, but C2 has various heuristics: it won’t try to vectorise a simple reduction, and 64 would probably be on the short side for most cases it would try to vectorise.

Acknowledging Runs

You might be tempted to transfer even more control to the callback, by accumulating runs and then calling the callback once per run. It simplifies the code to exclude incomplete start and end words from the run.


private interface RunConsumer {
    void acceptRun(int start, int end);
  }

  public void forEach(long[] bitmap, IntConsumer intConsumer, RunConsumer runConsumer) {
    int runStart = -1;
    for (int i = 0; i < bitmap.length; ++i) {
      long word = bitmap[i];
      if (word == -1L) {
        if (runStart == -1) {
          runStart = i;
        }
      } else {
        if (runStart != -1) {
          runConsumer.acceptRun(runStart * Long.SIZE, i * Long.SIZE);
          runStart = -1;
        }
        while (word != 0) {
          intConsumer.accept(Long.SIZE * i + Long.numberOfTrailingZeros(word));
          word ^= Long.lowestOneBit(word);
        }
      }
    }
    if (runStart != -1) {
      runConsumer.acceptRun(runStart * Long.SIZE, bitmap.length * Long.SIZE);
    }
  }

For a simple reduction, the extra complexity isn’t justified: you’re better off with the WordIterator.

Benchmark Mode Threads Samples Score Score Error (99.9%) Unit Param: scenario
reduce thrpt 1 10 160.502749 2.960568 ops/ms SPARSE_16_FULL_WORDS
reduce thrpt 1 10 7.294747 0.186678 ops/ms FULL
reduce thrpt 1 10 258.064511 8.902233 ops/ms ONE_BIT_PER_WORD
reduce thrpt 1 10 159.613877 3.424432 ops/ms SPARSE_1_16_WORD_RUN
reduceWithRunConsumer thrpt 1 10 251.683131 6.799639 ops/ms SPARSE_16_FULL_WORDS
reduceWithRunConsumer thrpt 1 10 37.809154 0.723198 ops/ms FULL
reduceWithRunConsumer thrpt 1 10 218.133560 13.756779 ops/ms ONE_BIT_PER_WORD
reduceWithRunConsumer thrpt 1 10 140.896826 8.495777 ops/ms SPARSE_1_16_WORD_RUN
reduceWithWordConsumer thrpt 1 10 257.961783 5.892072 ops/ms SPARSE_16_FULL_WORDS
reduceWithWordConsumer thrpt 1 10 43.909471 0.601319 ops/ms FULL
reduceWithWordConsumer thrpt 1 10 213.731758 20.398077 ops/ms ONE_BIT_PER_WORD
reduceWithWordConsumer thrpt 1 10 258.280428 11.316647 ops/ms SPARSE_1_16_WORD_RUN

It’s simplistic to measure this and conclude that this is a bad approach though. There are several other dimensions to this problem:

  1. Vectorised callbacks
  2. Inlining failures preventing optimisations
  3. The number of runs and their lengths (i.e. your data and how you structure it)

Vectorisable Callbacks

There are real benefits to batching up callbacks if the workload in the callback can be vectorised. The code doesn’t need to get much more complicated to start benefitting from larger iteration batches. Mapping each bit to a scaled and squared value from the data array and storing it into an output array illustrates this.


  @Benchmark
  public void map(Blackhole bh) {
    forEach(bitmap, i -> output[i] = data[i] * data[i] * factor);
    bh.consume(output);
  }

  @Benchmark
  public void mapWithWordConsumer(Blackhole bh) {
    forEach(bitmap, i -> output[0] = data[i] * factor, (WordConsumer) (index, word) -> {
      if (word != -1L) {
        throw new IllegalStateException();
      }
      for (int i = index * Long.SIZE; i < (index + 1) * Long.SIZE; ++i) {
        output[i] = data[i] * data[i] * factor;
      }
    });
    bh.consume(output);
  }

  @Benchmark
  public void mapWithRunConsumer(Blackhole bh) {
    forEach(bitmap, i -> output[0] = data[i] * factor, (RunConsumer) (start, end) -> {
      for (int i = start; i < end; ++i) {
        output[i] = data[i] * data[i] * factor;
      }
    });
    bh.consume(output);
  }

The RunConsumer does much better in the full case, never much worse than the WordConsumer and always better than the basic strategy – even when there is only one run in the entire bitset, or when there are a few full words in an otherwise sparse bitset.

Benchmark Mode Threads Samples Score Score Error (99.9%) Unit Param: scenario
map thrpt 1 10 127.876662 3.411741 ops/ms SPARSE_16_FULL_WORDS
map thrpt 1 10 10.598974 0.022404 ops/ms FULL
map thrpt 1 10 126.434666 18.608547 ops/ms ONE_BIT_PER_WORD
map thrpt 1 10 115.977840 20.449258 ops/ms SPARSE_1_16_WORD_RUN
mapWithRunConsumer thrpt 1 10 199.186167 8.138446 ops/ms SPARSE_16_FULL_WORDS
mapWithRunConsumer thrpt 1 10 64.230868 2.871434 ops/ms FULL
mapWithRunConsumer thrpt 1 10 219.963063 4.257561 ops/ms ONE_BIT_PER_WORD
mapWithRunConsumer thrpt 1 10 203.403804 6.907366 ops/ms SPARSE_1_16_WORD_RUN
mapWithWordConsumer thrpt 1 10 229.822235 5.276084 ops/ms SPARSE_16_FULL_WORDS
mapWithWordConsumer thrpt 1 10 48.381990 3.845642 ops/ms FULL
mapWithWordConsumer thrpt 1 10 218.907803 5.331011 ops/ms ONE_BIT_PER_WORD
mapWithWordConsumer thrpt 1 10 240.795280 10.204818 ops/ms SPARSE_1_16_WORD_RUN

This is simply because the callback was vectorised, and the style of the RunConsumer API allows this to be exploited. This can be seen with perfasm. Both the WordConsumer and RunConsumer are actually vectorised, but the thing to notice is that there are two hot regions in the WordConsumer benchmark: the iteration and the callback, this boundary is often crossed. On the other hand, the RunConsumer implementation spends most of its time in the callback.

WordConsumer


....[Hottest Region 1]..............................................................................
c2, com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub, version 172 (227 bytes) 

           0x000001c2aa13c788: ud2                       ;*athrow {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - jdk.internal.util.Preconditions::checkFromToIndex@21
                                                         ; - java.util.Objects::checkFromToIndex@4
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@47 (line 226)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
           0x000001c2aa13c78a: mov     r8d,ecx
  0.23%    0x000001c2aa13c78d: mov     ecx,r8d           ;*aload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@62 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  1.55%    0x000001c2aa13c790: vmovdqu ymm1,ymmword ptr [r9+r10*4+10h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@69 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.15%    0x000001c2aa13c797: vpmulld ymm1,ymm1,ymm1
  3.72%    0x000001c2aa13c79c: vpmulld ymm1,ymm1,ymm2
 16.02%    0x000001c2aa13c7a1: vmovdqu ymmword ptr [rdx+r10*4+10h],ymm1
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@78 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  1.69%    0x000001c2aa13c7a8: movsxd  r8,r10d
  1.55%    0x000001c2aa13c7ab: vmovdqu ymm1,ymmword ptr [r9+r8*4+30h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@69 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  1.46%    0x000001c2aa13c7b2: vpmulld ymm1,ymm1,ymm1
  1.71%    0x000001c2aa13c7b7: vpmulld ymm1,ymm1,ymm2
  3.20%    0x000001c2aa13c7bc: vmovdqu ymmword ptr [rdx+r8*4+30h],ymm1
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@78 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.07%    0x000001c2aa13c7c3: add     r10d,10h          ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@79 (line 227)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  1.70%    0x000001c2aa13c7c7: cmp     r10d,r11d
           0x000001c2aa13c7ca: jl      1c2aa13c790h      ;*putfield arg$1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/1453625478::&lt;init&gt;@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/1453625478::get$Lambda@5
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@10
                                                         ; - java.lang.invoke.LambdaForm$MH/1166726978::linkToTargetMethod@5
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@6 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.02%    0x000001c2aa13c7cc: mov     r8,qword ptr [r15+70h]  ; ImmutableOopMap{r9=Oop rdx=Oop rax=Oop r13=NarrowOop xmm0=Oop [144]=Oop [152]=Oop [48]=Oop }
                                                         ;*goto {reexecute=1 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@82 (line 227)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  1.50%    0x000001c2aa13c7d0: test    dword ptr [r8],eax  ;*goto {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@82 (line 227)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
                                                         ;   {poll}
  0.04%    0x000001c2aa13c7d3: cmp     r10d,r11d
           0x000001c2aa13c7d6: jl      1c2aa13c78ah
  0.05%    0x000001c2aa13c7d8: mov     r11d,dword ptr [rsp+5ch]
  0.02%    0x000001c2aa13c7dd: add     r11d,39h
  1.57%    0x000001c2aa13c7e1: mov     r8d,ecx
  0.02%    0x000001c2aa13c7e4: cmp     r8d,r11d
  0.06%    0x000001c2aa13c7e7: mov     ecx,80000000h
  0.02%    0x000001c2aa13c7ec: cmovl   r11d,ecx
  1.50%    0x000001c2aa13c7f0: cmp     r10d,r11d
           0x000001c2aa13c7f3: jnl     1c2aa13c819h
  0.02%    0x000001c2aa13c7f5: nop                       ;*aload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@62 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.06%    0x000001c2aa13c7f8: vmovdqu ymm1,ymmword ptr [r9+r10*4+10h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@69 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.21%    0x000001c2aa13c7ff: vpmulld ymm1,ymm1,ymm1
  2.16%    0x000001c2aa13c804: vpmulld ymm1,ymm1,ymm2
  1.80%    0x000001c2aa13c809: vmovdqu ymmword ptr [rdx+r10*4+10h],ymm1
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@78 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  1.56%    0x000001c2aa13c810: add     r10d,8h           ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@79 (line 227)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c814: cmp     r10d,r11d
           0x000001c2aa13c817: jl      1c2aa13c7f8h      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@59 (line 227)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c819: cmp     r10d,r8d
           0x000001c2aa13c81c: jnl     1c2aa13c83ah
  0.01%    0x000001c2aa13c81e: nop                       ;*aload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@62 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  1.58%    0x000001c2aa13c820: mov     ecx,dword ptr [r9+r10*4+10h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@69 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.03%    0x000001c2aa13c825: imul    ecx,ecx
  1.58%    0x000001c2aa13c828: imul    ecx,dword ptr [rsp+58h]
  0.03%    0x000001c2aa13c82d: mov     dword ptr [rdx+r10*4+10h],ecx
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@78 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  1.56%    0x000001c2aa13c832: inc     r10d              ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@79 (line 227)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c835: cmp     r10d,r8d
           0x000001c2aa13c838: jl      1c2aa13c820h      ;*putfield arg$1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/1453625478::&lt;init&gt;@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$43/1453625478::get$Lambda@5
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@10
                                                         ; - java.lang.invoke.LambdaForm$MH/1166726978::linkToTargetMethod@5
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@6 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  1.55%    0x000001c2aa13c83a: mov     r10,qword ptr [r15+70h]
  0.01%    0x000001c2aa13c83e: inc     esi               ; ImmutableOopMap{rax=Oop r13=NarrowOop xmm0=Oop [144]=Oop [152]=Oop [48]=Oop }
                                                         ;*goto {reexecute=1 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@78 (line 168)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.02%    0x000001c2aa13c840: test    dword ptr [r10],eax  ;*goto {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@78 (line 168)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
                                                         ;   {poll}
  0.02%    0x000001c2aa13c843: cmp     esi,dword ptr [rsp+0a0h]
           0x000001c2aa13c84a: jnl     1c2aa13cb2ah      ;*aload_1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@10 (line 169)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  1.54%    0x000001c2aa13c850: mov     r8,rax
  0.01%    0x000001c2aa13c853: mov     r14,qword ptr [rsp+90h]
  0.01%    0x000001c2aa13c85b: mov     rbx,qword ptr [rsp+50h]
  0.01%    0x000001c2aa13c860: mov     r10d,r13d
  1.54%    0x000001c2aa13c863: vmovq   rax,xmm0
  0.01%    0x000001c2aa13c868: mov     r9d,dword ptr [rsp+0a0h]
  0.02%    0x000001c2aa13c870: jmp     1c2aa13c904h
           0x000001c2aa13c875: mov     r13,qword ptr [rsp+98h]
           0x000001c2aa13c87d: mov     r8,qword ptr [rsp+68h]  ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@7 (line 168)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
           0x000001c2aa13c882: mov     ebp,dword ptr [r8+18h]  ;*getfield output {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@22 (line 141)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
           0x000001c2aa13c886: mov     r10,qword ptr [rsp+30h]
           0x000001c2aa13c88b: test    r10,r10
....................................................................................................
 53.26%  <total for region 1>

....[Hottest Region 2]..............................................................................
c2, com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub, version 172 (391 bytes) 

                                                         ; implicit exception: dispatches to 0x000001c2aa13cdd6
           0x000001c2aa13c8c8: test    r11d,r11d
           0x000001c2aa13c8cb: jne     1c2aa13cc5eh      ;*ifeq {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@30 (line 144)
           0x000001c2aa13c8d1: mov     ebx,1h            ;*invokespecial &lt;init&gt; {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::get$Lambda@5
                                                         ; - java.lang.invoke.DirectMethodHandle$Holder::invokeStatic@10
                                                         ; - java.lang.invoke.LambdaForm$MH/1166726978::linkToTargetMethod@5
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@12 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c8d6: mov     r8,qword ptr [rsp+0a0h]
  0.01%    0x000001c2aa13c8de: mov     r10d,dword ptr [r8+10h]  ;*getfield bitmap {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@2 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001c2aa13c8e2: mov     r9d,dword ptr [r12+r10*8+0ch]
                                                         ;*arraylength {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@6 (line 168)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
                                                         ; implicit exception: dispatches to 0x000001c2aa13cdc6
  0.04%    0x000001c2aa13c8e7: test    r9d,r9d
           0x000001c2aa13c8ea: jbe     1c2aa13cb2fh      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@7 (line 168)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001c2aa13c8f0: mov     ecx,r9d
           0x000001c2aa13c8f3: dec     ecx
           0x000001c2aa13c8f5: cmp     ecx,r9d
           0x000001c2aa13c8f8: jnb     1c2aa13cd1ah
           0x000001c2aa13c8fe: lea     rax,[r12+r10*8]   ;*getfield bitmap {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@2 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
           0x000001c2aa13c902: xor     esi,esi           ;*aload_1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@10 (line 169)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c904: mov     r11,qword ptr [rax+rsi*8+10h]
                                                         ;*laload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@13 (line 169)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  1.57%    0x000001c2aa13c909: cmp     r11,0ffffffffffffffffh
           0x000001c2aa13c90d: jne     1c2aa13cccah      ;*ifne {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@22 (line 170)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c913: mov     edx,dword ptr [r8+14h]  ;*getfield data {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@3 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c917: mov     edi,dword ptr [r12+rdx*8+0ch]
                                                         ;*arraylength {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@35 (line 225)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
                                                         ; implicit exception: dispatches to 0x000001c2aa13cda6
  0.01%    0x000001c2aa13c91c: mov     dword ptr [rsp+0a0h],r9d
  1.56%    0x000001c2aa13c924: mov     r13d,dword ptr [r8+0ch]  ;*getfield factor {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@11 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c928: mov     r11d,esi
  0.02%    0x000001c2aa13c92b: shl     r11d,6h           ;*imul {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@19 (line 223)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c92f: lea     r9,[r12+rdx*8]    ;*getfield data {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@3 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  1.55%    0x000001c2aa13c933: mov     ecx,r11d
  0.01%    0x000001c2aa13c936: add     ecx,40h           ;*imul {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@27 (line 224)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c939: mov     ebp,dword ptr [r8+18h]  ;*getfield output {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@7 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c93d: test    r11d,r11d
  1.55%    0x000001c2aa13c940: jl      1c2aa13ca62h      ;*iflt {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - jdk.internal.util.Preconditions::checkFromToIndex@1
                                                         ; - java.util.Objects::checkFromToIndex@4
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@36 (line 225)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c946: cmp     r11d,ecx
           0x000001c2aa13c949: jnle    1c2aa13ca62h      ;*if_icmpgt {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - jdk.internal.util.Preconditions::checkFromToIndex@6
                                                         ; - java.util.Objects::checkFromToIndex@4
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@36 (line 225)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c94f: cmp     ecx,edi
           0x000001c2aa13c951: jnle    1c2aa13ca62h      ;*if_icmple {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - jdk.internal.util.Preconditions::checkFromToIndex@11
                                                         ; - java.util.Objects::checkFromToIndex@4
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@36 (line 225)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.00%    0x000001c2aa13c957: mov     dword ptr [rsp+60h],ecx
  1.51%    0x000001c2aa13c95b: mov     dword ptr [rsp+5ch],r11d
  0.02%    0x000001c2aa13c960: mov     dword ptr [rsp+58h],r13d
  0.01%    0x000001c2aa13c965: mov     ecx,edi
  0.01%    0x000001c2aa13c967: vmovd   xmm1,edx
  1.48%    0x000001c2aa13c96b: vmovq   xmm0,rax
  0.02%    0x000001c2aa13c970: mov     r13d,r10d
  0.02%    0x000001c2aa13c973: mov     qword ptr [rsp+50h],rbx
  0.01%    0x000001c2aa13c978: mov     qword ptr [rsp+90h],r14
  1.52%    0x000001c2aa13c980: mov     rax,r8
  0.01%    0x000001c2aa13c983: mov     edi,dword ptr [r12+rbp*8+0ch]
                                                         ;*arraylength {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@46 (line 226)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
                                                         ; implicit exception: dispatches to 0x000001c2aa13cdb6
  0.01%    0x000001c2aa13c988: lea     rdx,[r12+rbp*8]   ;*getfield output {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@7 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.02%    0x000001c2aa13c98c: mov     r10d,dword ptr [rsp+60h]
  1.50%    0x000001c2aa13c991: cmp     r10d,edi
           0x000001c2aa13c994: jnle    1c2aa13cac2h      ;*if_icmple {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - jdk.internal.util.Preconditions::checkFromToIndex@11
                                                         ; - java.util.Objects::checkFromToIndex@4
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@47 (line 226)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13c99a: cmp     r11d,r10d
           0x000001c2aa13c99d: jnl     1c2aa13c83ah      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@59 (line 227)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.02%    0x000001c2aa13c9a3: cmp     r11d,ecx
           0x000001c2aa13c9a6: jnb     1c2aa13cc9ah
  0.01%    0x000001c2aa13c9ac: movsxd  r10,dword ptr [rsp+60h]
  1.58%    0x000001c2aa13c9b1: movsxd  r11,ecx
  0.01%    0x000001c2aa13c9b4: dec     r10
  0.02%    0x000001c2aa13c9b7: cmp     r10,r11
           0x000001c2aa13c9ba: jnb     1c2aa13cc9ah
  0.01%    0x000001c2aa13c9c0: mov     r11d,dword ptr [rsp+5ch]
  1.50%    0x000001c2aa13c9c5: cmp     r11d,edi
           0x000001c2aa13c9c8: jnb     1c2aa13cc9ah
  0.02%    0x000001c2aa13c9ce: movsxd  r11,edi
  0.02%    0x000001c2aa13c9d1: cmp     r10,r11
           0x000001c2aa13c9d4: jnb     1c2aa13cc9ah
  0.02%    0x000001c2aa13c9da: mov     r11d,edx
  1.62%    0x000001c2aa13c9dd: shr     r11d,2h
  0.02%    0x000001c2aa13c9e1: and     r11d,7h
  0.01%    0x000001c2aa13c9e5: add     r11d,dword ptr [rsp+5ch]
  0.02%    0x000001c2aa13c9ea: mov     r8d,3h
  1.55%    0x000001c2aa13c9f0: sub     r8d,r11d
  0.01%    0x000001c2aa13c9f3: and     r8d,7h
  0.01%    0x000001c2aa13c9f7: add     r8d,dword ptr [rsp+5ch]
  0.01%    0x000001c2aa13c9fc: inc     r8d
  1.58%    0x000001c2aa13c9ff: cmp     r8d,dword ptr [rsp+60h]
  0.02%    0x000001c2aa13ca04: mov     ecx,dword ptr [rsp+60h]
  0.02%    0x000001c2aa13ca08: cmovnle r8d,ecx
  0.01%    0x000001c2aa13ca0c: mov     r10d,dword ptr [rsp+5ch]
  1.54%    0x000001c2aa13ca11: mov     ebx,ecx           ;*aload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@62 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.11%    0x000001c2aa13ca13: mov     r11d,dword ptr [r9+r10*4+10h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@69 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  4.67%    0x000001c2aa13ca18: imul    r11d,r11d
  0.14%    0x000001c2aa13ca1c: imul    r11d,dword ptr [rsp+58h]
  4.67%    0x000001c2aa13ca22: mov     dword ptr [rdx+r10*4+10h],r11d
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@78 (line 228)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.16%    0x000001c2aa13ca27: inc     r10d              ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@79 (line 227)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  4.63%    0x000001c2aa13ca2a: cmp     r10d,r8d
           0x000001c2aa13ca2d: jl      1c2aa13ca13h      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@59 (line 227)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
  0.01%    0x000001c2aa13ca2f: mov     r11d,dword ptr [rsp+5ch]
  0.01%    0x000001c2aa13ca34: add     r11d,31h
  0.02%    0x000001c2aa13ca38: mov     r8d,ebx
  1.48%    0x000001c2aa13ca3b: cmp     r8d,r11d
  0.01%    0x000001c2aa13ca3e: mov     ebx,80000000h
  0.02%    0x000001c2aa13ca43: cmovl   r11d,ebx
  0.04%    0x000001c2aa13ca47: cmp     r10d,r11d
           0x000001c2aa13ca4a: jnl     1c2aa13c819h
  2.48%    0x000001c2aa13ca50: vpshufd xmm2,xmmword ptr [rsp+58h],0h
  2.82%    0x000001c2aa13ca57: vinserti128 ymm2,ymm2,xmm2,1h
  2.88%    0x000001c2aa13ca5d: jmp     1c2aa13c78dh      ;*aload_3 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - jdk.internal.util.Preconditions::checkFromToIndex@14
                                                         ; - java.util.Objects::checkFromToIndex@4
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareForWord@36 (line 225)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithWordConsumer$7@14 (line 140)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1872198645::acceptWord@6
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::forEach@30 (line 171)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::mapWithWordConsumer@17 (line 138)
                                                         ; - com.openkappa.simd.iterate.generated.BitSetIterator_mapWithWordConsumer_jmhTest::mapWithWordConsumer_thrpt_jmhStub@17 (line 142)
           0x000001c2aa13ca62: mov     qword ptr [rsp+90h],r14
           0x000001c2aa13ca6a: mov     qword ptr [rsp+28h],r8
....................................................................................................
 46.39%  <total for region 2>

RunConsumer


....[Hottest Region 1]..............................................................................
c2, com.openkappa.simd.iterate.BitSetIterator$$Lambda$44.1209658195::acceptRun, version 166 (816 bytes) 

           # parm1:    r9        = int
           #           [sp+0x50]  (sp of caller)
           0x0000016658954740: mov     r10d,dword ptr [rdx+8h]
           0x0000016658954744: shl     r10,3h
           0x0000016658954748: cmp     rax,r10
           0x000001665895474b: jne     166588c6d80h      ;   {runtime_call ic_miss_stub}
           0x0000016658954751: nop
           0x0000016658954754: nop     dword ptr [rax+rax+0h]
           0x000001665895475c: nop
         [Verified Entry Point]
  0.00%    0x0000016658954760: mov     dword ptr [rsp+0ffffffffffff9000h],eax
  0.00%    0x0000016658954767: push    rbp
           0x0000016658954768: sub     rsp,40h           ;*synchronization entry
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@-1
           0x000001665895476c: mov     ecx,dword ptr [rdx+0ch]  ;*getfield arg$1 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@1
  0.00%    0x000001665895476f: mov     ebx,dword ptr [r12+rcx*8+14h]
                                                         ;*getfield data {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@3 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
                                                         ; implicit exception: dispatches to 0x0000016658954b76
           0x0000016658954774: mov     eax,dword ptr [r12+rbx*8+0ch]
                                                         ;*arraylength {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@3 (line 211)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
                                                         ; implicit exception: dispatches to 0x0000016658954b8e
  0.06%    0x0000016658954779: mov     r11d,dword ptr [r12+rcx*8+0ch]
                                                         ;*getfield factor {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@11 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
           0x000001665895477e: mov     edi,dword ptr [r12+rcx*8+18h]
                                                         ;*getfield output {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@7 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
           0x0000016658954783: test    r8d,r8d
           0x0000016658954786: jl      16658954ab6h      ;*iflt {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - jdk.internal.util.Preconditions::checkFromToIndex@1
                                                         ; - java.util.Objects::checkFromToIndex@4
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@4 (line 211)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
           0x000001665895478c: cmp     r8d,r9d
           0x000001665895478f: jnle    16658954ae6h      ;*if_icmpgt {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - jdk.internal.util.Preconditions::checkFromToIndex@6
                                                         ; - java.util.Objects::checkFromToIndex@4
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@4 (line 211)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.00%    0x0000016658954795: cmp     r9d,eax
           0x0000016658954798: jnle    16658954b1ah      ;*if_icmple {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - jdk.internal.util.Preconditions::checkFromToIndex@11
                                                         ; - java.util.Objects::checkFromToIndex@4
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@4 (line 211)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
           0x000001665895479e: mov     ebp,dword ptr [r12+rdi*8+0ch]
                                                         ;*arraylength {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@11 (line 212)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
                                                         ; implicit exception: dispatches to 0x0000016658954b9e
  0.05%    0x00000166589547a3: cmp     r9d,ebp
           0x00000166589547a6: jnle    16658954b4ah      ;*if_icmple {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - jdk.internal.util.Preconditions::checkFromToIndex@11
                                                         ; - java.util.Objects::checkFromToIndex@4
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@12 (line 212)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.00%    0x00000166589547ac: cmp     r8d,r9d
           0x00000166589547af: jnl     16658954a81h      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@22 (line 213)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
           0x00000166589547b5: cmp     r8d,eax
           0x00000166589547b8: jnb     16658954a91h
  0.00%    0x00000166589547be: movsxd  r10,r9d
           0x00000166589547c1: movsxd  rcx,eax
           0x00000166589547c4: dec     r10
           0x00000166589547c7: cmp     r10,rcx
           0x00000166589547ca: jnb     16658954a91h
           0x00000166589547d0: cmp     r8d,ebp
           0x00000166589547d3: jnb     16658954a91h
           0x00000166589547d9: movsxd  rcx,ebp
  0.01%    0x00000166589547dc: cmp     r10,rcx
           0x00000166589547df: jnb     16658954a91h
  0.00%    0x00000166589547e5: shl     rdi,3h            ;*getfield output {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@7 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
           0x00000166589547e9: lea     rdx,[r12+rbx*8]   ;*getfield data {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@3 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
           0x00000166589547ed: mov     r10d,edi
  0.00%    0x00000166589547f0: shr     r10d,2h
  0.00%    0x00000166589547f4: and     r10d,7h
           0x00000166589547f8: add     r10d,r8d
           0x00000166589547fb: mov     ecx,3h
  0.00%    0x0000016658954800: sub     ecx,r10d
  0.00%    0x0000016658954803: and     ecx,7h
           0x0000016658954806: add     ecx,r8d
           0x0000016658954809: inc     ecx
  0.00%    0x000001665895480b: cmp     ecx,r9d
  0.00%    0x000001665895480e: cmovnle ecx,r9d           ;*aload_3 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@25 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.00%    0x0000016658954812: mov     r10d,dword ptr [rdx+r8*4+10h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.00%    0x0000016658954817: imul    r10d,r10d
  0.01%    0x000001665895481b: imul    r10d,r11d
  0.00%    0x000001665895481f: mov     dword ptr [rdi+r8*4+10h],r10d
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.00%    0x0000016658954824: inc     r8d               ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@41 (line 213)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.00%    0x0000016658954827: cmp     r8d,ecx
           0x000001665895482a: jl      16658954812h      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@22 (line 213)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
           0x000001665895482c: mov     r10d,r9d
           0x000001665895482f: add     r10d,0ffffff81h
  0.00%    0x0000016658954833: mov     ebx,80000000h
  0.00%    0x0000016658954838: cmp     r9d,r10d
           0x000001665895483b: cmovl   r10d,ebx
           0x000001665895483f: cmp     r8d,r10d
           0x0000016658954842: jnl     16658954a61h
  0.00%    0x0000016658954848: vmovd   xmm1,r11d
           0x000001665895484d: vpshufd xmm1,xmm1,0h
           0x0000016658954852: vinserti128 ymm1,ymm1,xmm1,1h  ;*goto {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@44 (line 213)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.00%    0x0000016658954858: nop     dword ptr [rax+rax+0h]  ;*aload_3 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@25 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.92%    0x0000016658954860: vmovdqu ymm0,ymmword ptr [rdx+r8*4+10h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  1.31%    0x0000016658954867: vpmulld ymm0,ymm0,ymm0
  1.74%    0x000001665895486c: vpmulld ymm0,ymm0,ymm1
  4.55%    0x0000016658954871: vmovdqu ymmword ptr [rdi+r8*4+10h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.69%    0x0000016658954878: movsxd  rcx,r8d
  0.01%    0x000001665895487b: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+30h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.41%    0x0000016658954881: vpmulld ymm0,ymm0,ymm0
  0.78%    0x0000016658954886: vpmulld ymm0,ymm0,ymm1
  0.83%    0x000001665895488b: vmovdqu ymmword ptr [rdi+rcx*4+30h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.25%    0x0000016658954891: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+50h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  1.29%    0x0000016658954897: vpmulld ymm0,ymm0,ymm0
  1.51%    0x000001665895489c: vpmulld ymm0,ymm0,ymm1
  3.65%    0x00000166589548a1: vmovdqu ymmword ptr [rdi+rcx*4+50h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.54%    0x00000166589548a7: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+70h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.31%    0x00000166589548ad: vpmulld ymm0,ymm0,ymm0
  0.47%    0x00000166589548b2: vpmulld ymm0,ymm0,ymm1
  1.11%    0x00000166589548b7: vmovdqu ymmword ptr [rdi+rcx*4+70h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.28%    0x00000166589548bd: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+90h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  1.17%    0x00000166589548c6: vpmulld ymm0,ymm0,ymm0
  1.89%    0x00000166589548cb: vpmulld ymm0,ymm0,ymm1
  3.56%    0x00000166589548d0: vmovdqu ymmword ptr [rdi+rcx*4+90h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.73%    0x00000166589548d9: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+0b0h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.21%    0x00000166589548e2: vpmulld ymm0,ymm0,ymm0
  0.34%    0x00000166589548e7: vpmulld ymm0,ymm0,ymm1
  1.29%    0x00000166589548ec: vmovdqu ymmword ptr [rdi+rcx*4+0b0h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.33%    0x00000166589548f5: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+0d0h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.97%    0x00000166589548fe: vpmulld ymm0,ymm0,ymm0
  1.90%    0x0000016658954903: vpmulld ymm0,ymm0,ymm1
  3.59%    0x0000016658954908: vmovdqu ymmword ptr [rdi+rcx*4+0d0h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.82%    0x0000016658954911: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+0f0h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.18%    0x000001665895491a: vpmulld ymm0,ymm0,ymm0
  0.29%    0x000001665895491f: vpmulld ymm0,ymm0,ymm1
  1.25%    0x0000016658954924: vmovdqu ymmword ptr [rdi+rcx*4+0f0h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.33%    0x000001665895492d: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+110h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  1.10%    0x0000016658954936: vpmulld ymm0,ymm0,ymm0
  2.11%    0x000001665895493b: vpmulld ymm0,ymm0,ymm1
  3.67%    0x0000016658954940: vmovdqu ymmword ptr [rdi+rcx*4+110h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.93%    0x0000016658954949: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+130h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.13%    0x0000016658954952: vpmulld ymm0,ymm0,ymm0
  0.25%    0x0000016658954957: vpmulld ymm0,ymm0,ymm1
  1.35%    0x000001665895495c: vmovdqu ymmword ptr [rdi+rcx*4+130h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.32%    0x0000016658954965: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+150h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.93%    0x000001665895496e: vpmulld ymm0,ymm0,ymm0
  2.16%    0x0000016658954973: vpmulld ymm0,ymm0,ymm1
  3.73%    0x0000016658954978: vmovdqu ymmword ptr [rdi+rcx*4+150h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.95%    0x0000016658954981: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+170h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.14%    0x000001665895498a: vpmulld ymm0,ymm0,ymm0
  0.21%    0x000001665895498f: vpmulld ymm0,ymm0,ymm1
  1.39%    0x0000016658954994: vmovdqu ymmword ptr [rdi+rcx*4+170h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.29%    0x000001665895499d: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+190h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  1.42%    0x00000166589549a6: vpmulld ymm0,ymm0,ymm0
  2.61%    0x00000166589549ab: vpmulld ymm0,ymm0,ymm1
  4.42%    0x00000166589549b0: vmovdqu ymmword ptr [rdi+rcx*4+190h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  1.01%    0x00000166589549b9: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+1b0h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.10%    0x00000166589549c2: vpmulld ymm0,ymm0,ymm0
  0.17%    0x00000166589549c7: vpmulld ymm0,ymm0,ymm1
  1.46%    0x00000166589549cc: vmovdqu ymmword ptr [rdi+rcx*4+1b0h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.27%    0x00000166589549d5: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+1d0h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
 13.60%    0x00000166589549de: vpmulld ymm0,ymm0,ymm0
  3.51%    0x00000166589549e3: vpmulld ymm0,ymm0,ymm1
  4.69%    0x00000166589549e8: vmovdqu ymmword ptr [rdi+rcx*4+1d0h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  1.00%    0x00000166589549f1: vmovdqu ymm0,ymmword ptr [rdx+rcx*4+1f0h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.11%    0x00000166589549fa: vpmulld ymm0,ymm0,ymm0
  0.15%    0x00000166589549ff: vpmulld ymm0,ymm0,ymm1
  1.46%    0x0000016658954a04: vmovdqu ymmword ptr [rdi+rcx*4+1f0h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.26%    0x0000016658954a0d: add     r8d,80h           ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@41 (line 213)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.01%    0x0000016658954a14: cmp     r8d,r10d
           0x0000016658954a17: jl      16658954860h      ;*goto {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@44 (line 213)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.00%    0x0000016658954a1d: mov     r14,qword ptr [r15+70h]  ; ImmutableOopMap{rdi=Oop rdx=Oop }
                                                         ;*goto {reexecute=1 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@44 (line 213)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.06%    0x0000016658954a21: test    dword ptr [r14],eax  ;*goto {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@44 (line 213)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
                                                         ;   {poll}
  0.17%    0x0000016658954a24: cmp     r8d,r10d
           0x0000016658954a27: jl      16658954860h
           0x0000016658954a2d: mov     r10d,r9d
           0x0000016658954a30: add     r10d,0fffffff9h
           0x0000016658954a34: cmp     r9d,r10d
  0.00%    0x0000016658954a37: cmovl   r10d,ebx
           0x0000016658954a3b: cmp     r8d,r10d
           0x0000016658954a3e: jnl     16658954a61h      ;*aload_3 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@25 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
           0x0000016658954a40: vmovdqu ymm0,ymmword ptr [rdx+r8*4+10h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.14%    0x0000016658954a47: vpmulld ymm0,ymm0,ymm0
  0.05%    0x0000016658954a4c: vpmulld ymm0,ymm0,ymm1
  0.03%    0x0000016658954a51: vmovdqu ymmword ptr [rdi+r8*4+10h],ymm0
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.04%    0x0000016658954a58: add     r8d,8h            ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@41 (line 213)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
           0x0000016658954a5c: cmp     r8d,r10d
           0x0000016658954a5f: jl      16658954a40h      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@22 (line 213)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
           0x0000016658954a61: cmp     r8d,r9d
           0x0000016658954a64: jnl     16658954a81h
           0x0000016658954a66: nop                       ;*aload_3 {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@25 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.00%    0x0000016658954a68: mov     ecx,dword ptr [rdx+r8*4+10h]
                                                         ;*iaload {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@31 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
           0x0000016658954a6d: imul    ecx,ecx
           0x0000016658954a70: imul    ecx,r11d
           0x0000016658954a74: mov     dword ptr [rdi+r8*4+10h],ecx
                                                         ;*iastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@40 (line 214)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.00%    0x0000016658954a79: inc     r8d               ;*iinc {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@41 (line 213)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
           0x0000016658954a7c: cmp     r8d,r9d
  0.00%    0x0000016658954a7f: jl      16658954a68h      ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::scaleSquareInRun@22 (line 213)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator::lambda$mapWithRunConsumer$9@14 (line 148)
                                                         ; - com.openkappa.simd.iterate.BitSetIterator$$Lambda$44/1209658195::acceptRun@6
  0.00%    0x0000016658954a81: vzeroupper
  0.00%    0x0000016658954a84: add     rsp,40h
           0x0000016658954a88: pop     rbp
  0.00%    0x0000016658954a89: mov     r10,qword ptr [r15+70h]
           0x0000016658954a8d: test    dword ptr [r10],eax  ;   {poll_return}
  0.00%    0x0000016658954a90: ret
           0x0000016658954a91: mov     edx,0ffffff86h
           0x0000016658954a96: mov     ebp,r9d
           0x0000016658954a99: mov     dword ptr [rsp],r11d
           0x0000016658954a9d: mov     dword ptr [rsp+4h],r8d
           0x0000016658954aa2: mov     dword ptr [rsp+8h],ebx
           0x0000016658954aa6: mov     dword ptr [rsp+0ch],edi
           0x0000016658954aaa: nop
           0x0000016658954aac: vzeroupper
           0x0000016658954aaf: call    166588c8a00h      ; ImmutableOopMap{[8]=NarrowOop [12]=NarrowOop }
                                                         ;*aload_3 {reexecute=0 rethrow=0 return_oop=0}
....................................................................................................
 96.10%  <total for region 1>

Inlining

So far, everything has been inlined. Java optimistically assumes you only have one implementation and aggressively inlines at first, deoptimising to add a branch when it sees a second implementation, deoptimising again and replacing with a virtual call if it sees a third implementation. This doesn’t matter much usually, but the cost of this not only dwarfs any savings in an iteration strategy; it also prevents various optimisations which can be applied if the code is inlined. Once again, passing a batch of work into the callback completely ameliorates this, because even if the call is virtual, the callback itself might be hot and aggressively optimised. I haven’t benchmarked this because I think the point is self-evident to anyone who would read this far.

Number of runs

It’s clear to see from the benchmark results that the best choice of iteration strategy is sensitive to what you want to do with the data, but also how it is arranged. It is well documented in database literature that real data sets tend to contain runs. If you are building a bitmap index on some attribute of your data, and you sort your data by that attribute, you will have as many bitmaps as you have attribute values, and each attribute value bitmap will contain a single run. This is almost true for any index on attributes correlated with the attribute chosen for the sort order, and is completely untrue for uncorellated attributes. There are a range of iteration strategies to choose from, and the best iteration strategy for one index may not be the best for another.

My benchmarks are available at github.

Posted on

Faster Floating Point Reductions

At the moment, I am working on a hobby project called SplitMap, which aims to evaluate aggregations over complex boolean expressions as fast as possible using the same high level constructs of the streams API. It’s already capable of performing logic that takes vanilla parallel streams 20ms in under 300μs, but I think sub 100μs is possible for these calculations. I have reached the stage where the bottleneck is floating point reductions: Java won’t vectorise these because the result would be numerically unstable. This is a bit limiting, because it often doesn’t matter very much: nobody represents money with floating point numbers, and if you’re solving stiff differential equations it won’t be numerical stability that stops you from using a more suitable language. The reality is, somebody somewhere probably really cares about this, and that’s probably why there’s no fastfp semantics in the language. This ancient proposal lay stagnant before being withdrawn, and several optimisations just can’t be implemented by the JIT compiler without violating language guarantees. An intrinsic for FMA only arrived in Java 9, 15 years after JSR 84 was withdrawn, and vectorised FMA is only available in JDK10, 18 years after JSR 84 was proposed. Computing an average is hardly numerical computing, but Java just isn’t a friendly language for this sort of thing.

Back to SplitMap. At this point, I’ve already maxed out the parallelism I can get from the fork join pool, so I want the code below to vectorise to squeeze out more performance:

  private double reduce(double[] data) {
    double reduced = 0D;
    for (int i = 0; i < data.length; ++i) {
      reduced += data[i];
    }
    return reduced;
  }

Looking at this with perfasm, it’s clear that unrolled scalar code is generated:


  0.00%    0x000001db0c6f5730: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+10h]
  6.17%    0x000001db0c6f5736: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+18h]
  6.15%    0x000001db0c6f573c: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+20h]
  6.23%    0x000001db0c6f5742: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+28h]
  6.16%    0x000001db0c6f5748: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+30h]
  6.37%    0x000001db0c6f574e: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+38h]
  6.22%    0x000001db0c6f5754: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+40h]
  6.21%    0x000001db0c6f575a: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+48h]
  6.11%    0x000001db0c6f5760: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+50h]
  6.18%    0x000001db0c6f5766: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+58h]
  6.18%    0x000001db0c6f576c: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+60h]
  6.30%    0x000001db0c6f5772: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+68h]
  6.23%    0x000001db0c6f5778: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+70h]
  6.33%    0x000001db0c6f577e: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+78h]
  6.25%    0x000001db0c6f5784: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+80h]
  6.31%    0x000001db0c6f578d: vaddsd  xmm0,xmm0,mmword ptr [rdx+rdi*8+88h]

Let’s do something really dumb – allocate an array! Then I’ll reduce vertically onto it, and do a small horizontal reduction at the end.


  @Benchmark
  public double reduceBuffered() {
    double[] buffer = new double[1024];
    for (int i = 0; i < data.length; ++i) {
      buffer[i & 1023] += data[i];
    }
    return reduce(buffer);
  }

I benchmarked this against reduce. Using size 1024 as a sanity check, it’s clear the work is just being done twice, which is reassuring. Once the array gets a bit bigger, the gains of (what I think should be) the faster vertical reduction prior to the horizontal reduction pays for the array allocation.

Benchmark Mode Threads Samples Score Score Error (99.9%) Unit Param: size
reduceBuffered thrpt 1 10 333.990079 3.542656 ops/ms 1024
reduceBuffered thrpt 1 10 18.639314 0.488300 ops/ms 65536
reduceBuffered thrpt 1 10 9.313916 0.343261 ops/ms 131072
reduceSimple thrpt 1 10 656.408971 1.771530 ops/ms 1024
reduceSimple thrpt 1 10 9.840417 0.032713 ops/ms 65536
reduceSimple thrpt 1 10 4.881353 0.076707 ops/ms 131072

The code in reduceBuffered produces a slightly different result because the elements are summated in a different order, though you’re hardly likely to notice. While, by any pragmatic definition, the function performs the same operation, it is semantically different. C2 actually doesn’t vectorise this code, and I have no idea why it’s so much faster! I won’t dwell on this because this is a dead end. In any case, here’s the perfasm output:


  0.20%    0x000001eaf2e49f50: vmovsd  xmm0,qword ptr [rdx+r9*8+10h]
  0.27%    0x000001eaf2e49f57: mov     ebx,r9d
  1.95%    0x000001eaf2e49f5a: add     ebx,0fh
  0.36%    0x000001eaf2e49f5d: and     ebx,3ffh
  0.21%    0x000001eaf2e49f63: mov     ecx,r9d
  0.30%    0x000001eaf2e49f66: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  2.96%    0x000001eaf2e49f6c: vaddsd  xmm0,xmm0,mmword ptr [r8+rcx*8+10h]
  0.61%    0x000001eaf2e49f73: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.50%    0x000001eaf2e49f7a: mov     ecx,r9d
  1.78%    0x000001eaf2e49f7d: inc     ecx
  0.37%    0x000001eaf2e49f7f: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.17%    0x000001eaf2e49f85: vmovsd  xmm0,qword ptr [r8+rcx*8+10h]
  0.49%    0x000001eaf2e49f8c: vaddsd  xmm0,xmm0,mmword ptr [rdx+r9*8+18h]
  2.51%    0x000001eaf2e49f93: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  1.21%    0x000001eaf2e49f9a: mov     ecx,r9d
  0.34%    0x000001eaf2e49f9d: add     ecx,2h
  0.90%    0x000001eaf2e49fa0: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.32%    0x000001eaf2e49fa6: vmovsd  xmm0,qword ptr [r8+rcx*8+10h]
  1.28%    0x000001eaf2e49fad: vaddsd  xmm0,xmm0,mmword ptr [rdx+r9*8+20h]
  1.43%    0x000001eaf2e49fb4: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  1.38%    0x000001eaf2e49fbb: vmovsd  xmm0,qword ptr [rdx+r9*8+28h]
  0.47%    0x000001eaf2e49fc2: mov     ecx,r9d
  0.28%    0x000001eaf2e49fc5: add     ecx,3h
  0.77%    0x000001eaf2e49fc8: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  1.34%    0x000001eaf2e49fce: vaddsd  xmm0,xmm0,mmword ptr [r8+rcx*8+10h]
  0.93%    0x000001eaf2e49fd5: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  1.36%    0x000001eaf2e49fdc: mov     ecx,r9d
  0.75%    0x000001eaf2e49fdf: add     ecx,4h
  0.43%    0x000001eaf2e49fe2: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.32%    0x000001eaf2e49fe8: vmovsd  xmm0,qword ptr [r8+rcx*8+10h]
  1.32%    0x000001eaf2e49fef: vaddsd  xmm0,xmm0,mmword ptr [rdx+r9*8+30h]
  1.32%    0x000001eaf2e49ff6: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  1.24%    0x000001eaf2e49ffd: mov     ecx,r9d
  0.40%    0x000001eaf2e4a000: add     ecx,5h
  0.79%    0x000001eaf2e4a003: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.46%    0x000001eaf2e4a009: vmovsd  xmm0,qword ptr [r8+rcx*8+10h]
  1.22%    0x000001eaf2e4a010: vaddsd  xmm0,xmm0,mmword ptr [rdx+r9*8+38h]
  4.18%    0x000001eaf2e4a017: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  1.61%    0x000001eaf2e4a01e: mov     ecx,r9d
  0.24%    0x000001eaf2e4a021: add     ecx,6h
  0.34%    0x000001eaf2e4a024: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.69%    0x000001eaf2e4a02a: vmovsd  xmm0,qword ptr [r8+rcx*8+10h]
  1.55%    0x000001eaf2e4a031: vaddsd  xmm0,xmm0,mmword ptr [rdx+r9*8+40h]
  0.95%    0x000001eaf2e4a038: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  1.97%    0x000001eaf2e4a03f: mov     ecx,r9d
  0.37%    0x000001eaf2e4a042: add     ecx,7h
  0.20%    0x000001eaf2e4a045: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.32%    0x000001eaf2e4a04b: vmovsd  xmm0,qword ptr [r8+rcx*8+10h]
  1.95%    0x000001eaf2e4a052: vaddsd  xmm0,xmm0,mmword ptr [rdx+r9*8+48h]
  0.92%    0x000001eaf2e4a059: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  1.95%    0x000001eaf2e4a060: mov     ecx,r9d
  0.42%    0x000001eaf2e4a063: add     ecx,8h
  0.35%    0x000001eaf2e4a066: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.20%    0x000001eaf2e4a06c: vmovsd  xmm0,qword ptr [r8+rcx*8+10h]
  1.97%    0x000001eaf2e4a073: vaddsd  xmm0,xmm0,mmword ptr [rdx+r9*8+50h]
  1.22%    0x000001eaf2e4a07a: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  1.67%    0x000001eaf2e4a081: mov     ecx,r9d
  0.48%    0x000001eaf2e4a084: add     ecx,9h
  0.39%    0x000001eaf2e4a087: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.32%    0x000001eaf2e4a08d: vmovsd  xmm0,qword ptr [r8+rcx*8+10h]
  1.66%    0x000001eaf2e4a094: vaddsd  xmm0,xmm0,mmword ptr [rdx+r9*8+58h]
  1.14%    0x000001eaf2e4a09b: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  1.45%    0x000001eaf2e4a0a2: mov     ecx,r9d
  0.65%    0x000001eaf2e4a0a5: add     ecx,0ah
  0.49%    0x000001eaf2e4a0a8: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.39%    0x000001eaf2e4a0ae: vmovsd  xmm0,qword ptr [r8+rcx*8+10h]
  1.45%    0x000001eaf2e4a0b5: vaddsd  xmm0,xmm0,mmword ptr [rdx+r9*8+60h]
  1.32%    0x000001eaf2e4a0bc: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  1.39%    0x000001eaf2e4a0c3: mov     ecx,r9d
  0.39%    0x000001eaf2e4a0c6: add     ecx,0bh
  0.65%    0x000001eaf2e4a0c9: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.53%    0x000001eaf2e4a0cf: vmovsd  xmm0,qword ptr [r8+rcx*8+10h]
  1.37%    0x000001eaf2e4a0d6: vaddsd  xmm0,xmm0,mmword ptr [rdx+r9*8+68h]
  1.22%    0x000001eaf2e4a0dd: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  1.46%    0x000001eaf2e4a0e4: mov     ecx,r9d
  0.42%    0x000001eaf2e4a0e7: add     ecx,0ch
  0.40%    0x000001eaf2e4a0ea: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.60%    0x000001eaf2e4a0f0: vmovsd  xmm0,qword ptr [r8+rcx*8+10h]
  1.47%    0x000001eaf2e4a0f7: vaddsd  xmm0,xmm0,mmword ptr [rdx+r9*8+70h]
  1.04%    0x000001eaf2e4a0fe: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  1.74%    0x000001eaf2e4a105: mov     ecx,r9d
  0.37%    0x000001eaf2e4a108: add     ecx,0dh
  0.43%    0x000001eaf2e4a10b: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.36%    0x000001eaf2e4a111: vmovsd  xmm0,qword ptr [r8+rcx*8+10h]
  1.68%    0x000001eaf2e4a118: vaddsd  xmm0,xmm0,mmword ptr [rdx+r9*8+78h]
  2.82%    0x000001eaf2e4a11f: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  2.04%    0x000001eaf2e4a126: mov     ecx,r9d
  0.19%    0x000001eaf2e4a129: add     ecx,0eh
  0.29%    0x000001eaf2e4a12c: and     ecx,3ffh          ;*iand {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@22 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)
  0.36%    0x000001eaf2e4a132: vmovsd  xmm0,qword ptr [r8+rcx*8+10h]
  2.02%    0x000001eaf2e4a139: vaddsd  xmm0,xmm0,mmword ptr [rdx+r9*8+80h]
  0.76%    0x000001eaf2e4a143: vmovsd  qword ptr [r8+rcx*8+10h],xmm0
  1.99%    0x000001eaf2e4a14a: vmovsd  xmm0,qword ptr [rdx+r9*8+88h]
  0.39%    0x000001eaf2e4a154: vaddsd  xmm0,xmm0,mmword ptr [r8+rbx*8+10h]
  0.56%    0x000001eaf2e4a15b: vmovsd  qword ptr [r8+rbx*8+10h],xmm0
                                                         ;*dastore {reexecute=0 rethrow=0 return_oop=0}
                                                         ; - com.openkappa.simd.reduction.ReduceArray::reduceBuffered@32 (line 36)
                                                         ; - com.openkappa.simd.reduction.generated.ReduceArray_reduceBuffered_jmhTest::reduceBuffered_thrpt_jmhStub@17 (line 119)

Using the same idea, but employing a trick I’ve used before for matrix multiplication, the code gets a lot faster!

  @Benchmark
  public double reduceVectorised() {
    double[] buffer = new double[1024];
    double[] temp = new double[1024];
    for (int i = 0; i < data.length >>> 10; ++i) {
      System.arraycopy(data, i * 1024, temp, 0,  temp.length);
      for (int j = 0; j < 1024; ++j) {
        buffer[j] += temp[j];
      }
    }
    return reduce(buffer);
  }

This generates a vectorised main loop:


  0.05%    0x000001e3fc0d71e0: vmovdqu ymm0,ymmword ptr [r9+r10*8+10h]
  0.16%    0x000001e3fc0d71e7: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+10h]
  1.26%    0x000001e3fc0d71ee: vmovdqu ymmword ptr [r13+r10*8+10h],ymm0
  0.39%    0x000001e3fc0d71f5: vmovdqu ymm0,ymmword ptr [r9+r10*8+30h]
  0.18%    0x000001e3fc0d71fc: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+30h]
  0.93%    0x000001e3fc0d7203: vmovdqu ymmword ptr [r13+r10*8+30h],ymm0
  0.68%    0x000001e3fc0d720a: vmovdqu ymm0,ymmword ptr [r9+r10*8+50h]
  0.17%    0x000001e3fc0d7211: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+50h]
  0.86%    0x000001e3fc0d7218: vmovdqu ymmword ptr [r13+r10*8+50h],ymm0
  0.73%    0x000001e3fc0d721f: vmovdqu ymm0,ymmword ptr [r9+r10*8+70h]
  0.19%    0x000001e3fc0d7226: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+70h]
  0.86%    0x000001e3fc0d722d: vmovdqu ymmword ptr [r13+r10*8+70h],ymm0
  0.78%    0x000001e3fc0d7234: vmovdqu ymm0,ymmword ptr [r9+r10*8+90h]
  0.17%    0x000001e3fc0d723e: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+90h]
  0.75%    0x000001e3fc0d7248: vmovdqu ymmword ptr [r13+r10*8+90h],ymm0
  0.84%    0x000001e3fc0d7252: vmovdqu ymm0,ymmword ptr [r9+r10*8+0b0h]
  0.15%    0x000001e3fc0d725c: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+0b0h]
  0.64%    0x000001e3fc0d7266: vmovdqu ymmword ptr [r13+r10*8+0b0h],ymm0
  0.92%    0x000001e3fc0d7270: vmovdqu ymm0,ymmword ptr [r9+r10*8+0d0h]
  0.15%    0x000001e3fc0d727a: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+0d0h]
  0.71%    0x000001e3fc0d7284: vmovdqu ymmword ptr [r13+r10*8+0d0h],ymm0
  0.91%    0x000001e3fc0d728e: vmovdqu ymm0,ymmword ptr [r9+r10*8+0f0h]
  0.15%    0x000001e3fc0d7298: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+0f0h]
  0.74%    0x000001e3fc0d72a2: vmovdqu ymmword ptr [r13+r10*8+0f0h],ymm0
  0.96%    0x000001e3fc0d72ac: vmovdqu ymm0,ymmword ptr [r9+r10*8+110h]
  0.12%    0x000001e3fc0d72b6: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+110h]
  0.70%    0x000001e3fc0d72c0: vmovdqu ymmword ptr [r13+r10*8+110h],ymm0
  0.99%    0x000001e3fc0d72ca: vmovdqu ymm0,ymmword ptr [r9+r10*8+130h]
  0.13%    0x000001e3fc0d72d4: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+130h]
  0.71%    0x000001e3fc0d72de: vmovdqu ymmword ptr [r13+r10*8+130h],ymm0
  0.94%    0x000001e3fc0d72e8: vmovdqu ymm0,ymmword ptr [r9+r10*8+150h]
  0.12%    0x000001e3fc0d72f2: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+150h]
  0.70%    0x000001e3fc0d72fc: vmovdqu ymmword ptr [r13+r10*8+150h],ymm0
  1.01%    0x000001e3fc0d7306: vmovdqu ymm0,ymmword ptr [r9+r10*8+170h]
  0.14%    0x000001e3fc0d7310: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+170h]
  0.75%    0x000001e3fc0d731a: vmovdqu ymmword ptr [r13+r10*8+170h],ymm0
  1.00%    0x000001e3fc0d7324: vmovdqu ymm0,ymmword ptr [r9+r10*8+190h]
  0.13%    0x000001e3fc0d732e: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+190h]
  0.67%    0x000001e3fc0d7338: vmovdqu ymmword ptr [r13+r10*8+190h],ymm0
  0.97%    0x000001e3fc0d7342: vmovdqu ymm0,ymmword ptr [r9+r10*8+1b0h]
  0.14%    0x000001e3fc0d734c: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+1b0h]
  0.72%    0x000001e3fc0d7356: vmovdqu ymmword ptr [r13+r10*8+1b0h],ymm0
  0.99%    0x000001e3fc0d7360: vmovdqu ymm0,ymmword ptr [r9+r10*8+1d0h]
  0.12%    0x000001e3fc0d736a: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+1d0h]
  0.69%    0x000001e3fc0d7374: vmovdqu ymmword ptr [r13+r10*8+1d0h],ymm0
  0.96%    0x000001e3fc0d737e: vmovdqu ymm0,ymmword ptr [r9+r10*8+1f0h]
  0.14%    0x000001e3fc0d7388: vaddpd  ymm0,ymm0,ymmword ptr [r13+r10*8+1f0h]
  0.70%    0x000001e3fc0d7392: vmovdqu ymmword ptr [r13+r10*8+1f0h],ymm0

This implementation is more than 3x faster than the original code, which includes the fuss of the buffers and copies. Wouldn’t it be nice to be able to opt in to fast floating point semantics somehow? Here are the final results (as usual, this is a throughput benchmark and higher is better):

Benchmark Mode Threads Samples Score Score Error (99.9%) Unit Param: size
reduceBuffered thrpt 1 10 329.935462 6.295871 ops/ms 1024
reduceBuffered thrpt 1 10 18.380467 0.455724 ops/ms 65536
reduceBuffered thrpt 1 10 9.257122 0.402876 ops/ms 131072
reduceSimple thrpt 1 10 654.809021 5.812795 ops/ms 1024
reduceSimple thrpt 1 10 9.694730 0.325011 ops/ms 65536
reduceSimple thrpt 1 10 4.772520 0.265691 ops/ms 131072
reduceVectorised thrpt 1 10 287.712794 27.492846 ops/ms 1024
reduceVectorised thrpt 1 10 34.454235 1.293985 ops/ms 65536
reduceVectorised thrpt 1 10 17.867701 0.813367 ops/ms 131072

The benchmark is on github.

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L’esprit de l’escalier

L’esprit de l’escalier is the inability to respond until it’s too late to bother. Perhaps not until you’ve reached the bottom of a staircase, having had an altercation at the top. You’re most likely to have experienced this if you are at all introverted and have been to a job interview, having only managed to find solutions to simple problems once you find yourself alone on a train full of strangers. The more I ponder the psychology of this phenomenon, the more it fascinates me.

Some programmers dread brain teasers, claiming they are irrelevant to the job. I think this is wrong. In reality, so-called brain teasers are valid tests for application developers because they tend to be questions about programming translated into some other – admittedly, often fanciful – domain. They measure your ability to interpret requirements. I think if you try to assess this in person, the outcome often depends on personality types.

Unwrapping the Riddle

Here’s an odd puzzle with a programming question hiding somewhere inside it.

There are 64 bottles of wine, and one is poisoned. In three days’ time there will be a banquet and you must make sure none of the guests are poisoned. The poison takes between two and two-and-a-half days to kill a man, but you can risk the lives of as many of 32 prisoners as you like to find the poisoned wine bottle. What’s the smallest number of prisoners you can use to find the poisoned bottle?

You may have seen this puzzle before and get out of jail free, and many websites exist to allow people to research these problems for a reason. But, phrased another way, you are actually being asked a simple programming question:

A 64-bit integer has a value equal to a power of two. Find its logarithm in as few steps as possible.

OK! Simple! Only one bit is set, it just needs to be found. The logarithm is the number of zeroes less significant than the bit. The set bit is either in the top half or the bottom half, so test this recursively. We can find the index of the bit by using a sequence of independent bit masks, incrementing a counter differently for each mask which intersects with the value. The code is very simple:


  private static int indexOfFirstBit(long value) {
    int index = 0;
    int temp;
    if ((value & 0xFFFFFFFF00000000L) != 0) { 
      index += 32;
      temp = (int)(value >>> 32);
    } else {
      temp = (int)value;
    }
    if ((temp & 0xFFFF0000) != 0) { 
      index += 16;
      temp >>>= 16;
    }
    if ((temp & 0xFF00) != 0) { 
      index += 8;
      temp >>>= 8;
    }
    if ((temp & 0xF0) != 0) {
      index += 4;
      temp >>>= 4;
    }
    if ((temp & 0xC) != 0) {
      index += 2;
      temp >>>= 2;
    }
    if ((temp & 0x2) != 0) {
      index += 1;
    }
    return index;
  }

The idea is that you keep halving the size of the problem, and add the width of the zero part of each mask that passes (counting from the right). This can be rearranged but the code above is most obvious. You may even recognise that this is equivalent to the x86 instruction TZCNT, which in Java is accessible via the intrinsic Long.numberOfTrailingZeros.

So, going back to la-la land, you only need to risk the lives of six prisoners. All you have to do is ask each of the six prisoners to drink half of the bottles, the first one drinks from the first 32 bottles, the second from the first 16 and the third 16, and so on until the sixth prisoner who drinks from every other bottle. Before three days are up, up to six prisoners will die. If prisoner one dies, you know the poisoned bottle is in the second half. If prisoner two also dies, you know it’s in the third quarter. If the sixth prisoner doesn’t die, you know the poisoned bottle is one of the odd numbers.

Psychology and Interactive Problem Solving

Some people have seen these problems before, others enjoy solving them collaboratively, others instantly recognise solutions. Why does this only come to mind on the train home for some people? Well, it could be stupidity, but I think it’s purely psychological. You may be the sort of person who doesn’t want to solve a problem, even a simple one like this, interactively. Perhaps it feels invasive to reveal your precise thought processes to someone you just met, and aren’t sure you like yet. You might find you take your work with you on walks, or come up with your best ideas in the shower. In short, you may just be an introvert.

There’s a darker side to this psychological cause of failure. You may find that your interviewer is actually an interrogator, is trying to insult your ego, and you’ll feel drawn to defend yourself. The more you defend yourself, the less you can commit to a logical thought process; you become emotional. Your thoughts become jumbled as your emotional defence takes over. You focus on how you are being judged, that you were being judged five seconds ago and still haven’t solved the problem, that you are being judged yet more harshly now. You aren’t actually thinking about the problem at all any more. You aren’t being tested on your ability to solve the problem, but on your ability to solve the problem and defend your self esteem at the same time. Some people fail at this.

I actually think this is fair game in many cases. For instance, if you want to be an Army Officer, you can’t get flustered and be allowed to be thrown off your game like this: people might be shooting at you! For programmers, however, I’m not sure. Most programmers are used to the feeling of being in “flow” – the feeling of being immersed in the task at hand, knowledge instantly accessible. There’s never another person there when you’re in flow. I suppose a programmer in flow is a lot like Schrödinger’s Cat – you destroy it just by interacting with it.

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Building RoaringBitmaps from Streams

RoaringBitmap is a fast compressed bitset format. In the Java implementation of Roaring, it was until recently preferential to build a bitset in one go from sorted data; there were performance penalties of varying magnitude for incremental or unordered insertions. In a recent pull request, I wanted to improve incremental monotonic insertion so I could build bitmaps from streams, but sped up unsorted batch creation significantly by accident.

Incremental Ordered Insertion

If you want to build a bitmap, you can do so efficiently with the RoaringBitmap.bitmapOf factory method.


int[] data = ...
RoaringBitmap bitmap = RoaringBitmap.bitmapOf(data);

However, I often find that I want to stream integers into a bitmap. Given that the integers being inserted into a bitmap often represent indices into an array, such a stream is likely to be monotonic. You might implement this like so:


IntStream stream = ...
RoaringBitmap bitmap = new RoaringBitmap();
stream.forEach(bitmap::add);

While this is OK, it has a few inefficiencies compared to the batch creation method.

  • Indirection: the container being written to must be located on each insertion
  • Eagerness: the cardinality must be kept up to date on each insertion
  • Allocation pressure: the best container type can’t be known in advance. Choice of container, and therefore the instance, may change as data is inserted.

You could also collect the stream into an int[] and use the batch method, but it could be a large temporary object with obvious drawbacks.

OrderedWriter

The solution I proposed is to create a writer object (OrderedWriter) which allocates a small buffer of 8KB, to use as a bitmap large enough to cover 16 bits. The stream to bitmap code becomes:


IntStream stream = ...
RoaringBitmap bitmap = new RoaringBitmap();
OrderedWriter writer = new OrderedWriter(bitmap);
stream.forEach(writer::add);
writer.flush(); // clear the buffer out

This is implemented so that changes in key (where the most significant 16 bits of each integer is stored) trigger a flush of the buffer.


  public void add(int value) {
    short key = Util.highbits(value);
    short low = Util.lowbits(value);
    if (key != currentKey) {
      if (Util.compareUnsigned(key, currentKey) < 0) {
        throw new IllegalStateException("Must write in ascending key order");
      }
      flush();
    }
    int ulow = low & 0xFFFF;
    bitmap[(ulow >>> 6)] |= (1L << ulow);
    currentKey = key;
    dirty = true;
  }

When a flush occurs, a container type is chosen and appended to the bitmap’s prefix index.


  public void flush() {
    if (dirty) {
      RoaringArray highLowContainer = underlying.highLowContainer;
      // we check that it's safe to append since RoaringArray.append does no validation
      if (highLowContainer.size > 0) {
        short key = highLowContainer.getKeyAtIndex(highLowContainer.size - 1);
        if (Util.compareUnsigned(currentKey, key) <= 0) {
          throw new IllegalStateException("Cannot write " + currentKey + " after " + key);
        }
      }
      highLowContainer.append(currentKey, chooseBestContainer());
      clearBitmap();
      dirty = false;
    }
  }

There are significant performance advantages in this approach. There is no indirection cost, and no searches in the prefix index for containers: the writes are just buffered. The buffer is small enough to fit in cache, and containers only need to be created when the writer is flushed, which happens whenever a new key is seen, or when flush is called manually. During a flush, the cardinality can be computed in one go, the best container can be chosen, and run optimisation only has to happen once. Computing the cardinality is the only bottleneck – it requires 1024 calls to Long.bitCount which can’t be vectorised in a language like Java. It can’t be incremented on insertion without either sacrificing idempotence or incurring the cost of a membership check. After the flush, the buffer needs to be cleared, using a call to Arrays.fill which is vectorised. So, despite the cost of the buffer, this can be quite efficient.

This approach isn’t universally applicable. For instance, you must write data in ascending order of the most significant 16 bits. You must also remember to flush the writer when you’re finished: until you’ve called flush, the data in the last container may not be in the bitmap. For my particular use case, this is reasonable. However, there are times when this is not fit for purpose, such as if you are occasionally inserting values and expect them to be available to queries immediately. In general, if you don’t know when you’ll stop adding data to the bitmap, this isn’t a good fit because you won’t know when to call flush.

Benchmark

The RoaringBitmap project is a big user of JMH, and most pull requests require benchmarks as evidence of performance improvement. I benchmarked the two approaches, varying bitmap sizes and randomness (likelihood of there not being a compressible run), and was amazed to find that this approach actually beats having a sorted array and using RoaringBitmap.bitmapOf. Less surprising was beating the existing API for incremental adds (this was the goal in the first place). Lower is better:

Benchmark (randomness) (size) Mode Cnt Score Error Units
buildRoaringBitmap 0.1 10000 avgt 5 54.263 3.393 us/op
buildRoaringBitmap 0.1 100000 avgt 5 355.188 15.234 us/op
buildRoaringBitmap 0.1 1000000 avgt 5 3567.839 135.149 us/op
buildRoaringBitmap 0.1 10000000 avgt 5 31982.046 1227.325 us/op
buildRoaringBitmap 0.5 10000 avgt 5 53.855 0.887 us/op
buildRoaringBitmap 0.5 100000 avgt 5 357.671 14.111 us/op
buildRoaringBitmap 0.5 1000000 avgt 5 3556.152 243.671 us/op
buildRoaringBitmap 0.5 10000000 avgt 5 34385.971 3864.143 us/op
buildRoaringBitmap 0.9 10000 avgt 5 59.354 10.385 us/op
buildRoaringBitmap 0.9 100000 avgt 5 374.245 54.485 us/op
buildRoaringBitmap 0.9 1000000 avgt 5 3712.684 657.964 us/op
buildRoaringBitmap 0.9 10000000 avgt 5 37223.976 4691.297 us/op
incrementalNativeAdd 0.1 10000 avgt 5 115.213 31.909 us/op
incrementalNativeAdd 0.1 100000 avgt 5 911.925 127.922 us/op
incrementalNativeAdd 0.1 1000000 avgt 5 8889.49 320.821 us/op
incrementalNativeAdd 0.1 10000000 avgt 5 102819.877 14247.868 us/op
incrementalNativeAdd 0.5 10000 avgt 5 116.878 28.232 us/op
incrementalNativeAdd 0.5 100000 avgt 5 947.076 128.255 us/op
incrementalNativeAdd 0.5 1000000 avgt 5 7190.443 202.012 us/op
incrementalNativeAdd 0.5 10000000 avgt 5 98843.303 4325.924 us/op
incrementalNativeAdd 0.9 10000 avgt 5 101.694 6.579 us/op
incrementalNativeAdd 0.9 100000 avgt 5 816.411 65.678 us/op
incrementalNativeAdd 0.9 1000000 avgt 5 9114.624 412.152 us/op
incrementalNativeAdd 0.9 10000000 avgt 5 108793.694 22562.527 us/op
incrementalUseOrderedWriter 0.1 10000 avgt 5 23.573 5.962 us/op
incrementalUseOrderedWriter 0.1 100000 avgt 5 289.588 36.814 us/op
incrementalUseOrderedWriter 0.1 1000000 avgt 5 2785.659 49.385 us/op
incrementalUseOrderedWriter 0.1 10000000 avgt 5 29489.758 2601.39 us/op
incrementalUseOrderedWriter 0.5 10000 avgt 5 23.57 1.536 us/op
incrementalUseOrderedWriter 0.5 100000 avgt 5 276.488 9.662 us/op
incrementalUseOrderedWriter 0.5 1000000 avgt 5 2799.408 198.77 us/op
incrementalUseOrderedWriter 0.5 10000000 avgt 5 28313.626 1976.042 us/op
incrementalUseOrderedWriter 0.9 10000 avgt 5 22.345 1.574 us/op
incrementalUseOrderedWriter 0.9 100000 avgt 5 280.205 36.987 us/op
incrementalUseOrderedWriter 0.9 1000000 avgt 5 2779.732 93.456 us/op
incrementalUseOrderedWriter 0.9 10000000 avgt 5 30568.591 2140.826 us/op

These benchmarks don’t go far enough to support replacing RoaringBitmap.bitmapOf.

Unsorted Input Data

In the cases benchmarked, this approach seems to be worthwhile. I can’t actually think of a case where someone would want to build a bitmap from unsorted data, but it occurred to me that this approach might be fast enough to cover the cost of a sort. OrderedWriter is also relaxed enough that it only needs the most significant 16 bits to be monotonic, so a full sort isn’t necessary. Implementing a radix sort on the most significant 16 bits (stable in the least significant 16 bits), prior to incremental insertion via an OrderedWriter, leads to huge increases in performance over RoaringBitmap.bitmapOf. The implementation is as follows:


  public static RoaringBitmap bitmapOfUnordered(final int... data) {
    partialRadixSort(data);
    RoaringBitmap bitmap = new RoaringBitmap();
    OrderedWriter writer = new OrderedWriter(bitmap);
    for (int i : data) {
      writer.add(i);
    }
    writer.flush();
    return bitmap;
  }

It did very well, according to benchmarks, even against various implementations of sort prior to RoaringBitmap.bitmapOf. Lower is better:

Benchmark (randomness) (size) Mode Cnt Score Error Units
bitmapOf 0.1 10000 avgt 5 1058.106 76.013 us/op
bitmapOf 0.1 100000 avgt 5 12323.905 976.68 us/op
bitmapOf 0.1 1000000 avgt 5 171812.526 9593.879 us/op
bitmapOf 0.1 10000000 avgt 5 3376296.157 170362.195 us/op
bitmapOf 0.5 10000 avgt 5 1096.663 477.795 us/op
bitmapOf 0.5 100000 avgt 5 12836.177 1674.54 us/op
bitmapOf 0.5 1000000 avgt 5 171998.126 4176 us/op
bitmapOf 0.5 10000000 avgt 5 3707804.439 974532.361 us/op
bitmapOf 0.9 10000 avgt 5 1124.881 65.673 us/op
bitmapOf 0.9 100000 avgt 5 14585.589 1894.788 us/op
bitmapOf 0.9 1000000 avgt 5 198506.813 8552.218 us/op
bitmapOf 0.9 10000000 avgt 5 3723942.934 423704.363 us/op
bitmapOfUnordered 0.1 10000 avgt 5 174.583 17.475 us/op
bitmapOfUnordered 0.1 100000 avgt 5 1768.613 86.543 us/op
bitmapOfUnordered 0.1 1000000 avgt 5 17889.705 135.714 us/op
bitmapOfUnordered 0.1 10000000 avgt 5 192645.352 6482.726 us/op
bitmapOfUnordered 0.5 10000 avgt 5 157.351 3.254 us/op
bitmapOfUnordered 0.5 100000 avgt 5 1674.919 90.138 us/op
bitmapOfUnordered 0.5 1000000 avgt 5 16900.458 778.999 us/op
bitmapOfUnordered 0.5 10000000 avgt 5 185399.32 4383.485 us/op
bitmapOfUnordered 0.9 10000 avgt 5 145.642 1.257 us/op
bitmapOfUnordered 0.9 100000 avgt 5 1515.845 82.914 us/op
bitmapOfUnordered 0.9 1000000 avgt 5 15807.597 811.048 us/op
bitmapOfUnordered 0.9 10000000 avgt 5 167863.49 3501.132 us/op
partialSortThenBitmapOf 0.1 10000 avgt 5 1060.152 168.802 us/op
partialSortThenBitmapOf 0.1 100000 avgt 5 10942.731 347.583 us/op
partialSortThenBitmapOf 0.1 1000000 avgt 5 100606.506 24705.341 us/op
partialSortThenBitmapOf 0.1 10000000 avgt 5 1035448.545 157383.713 us/op
partialSortThenBitmapOf 0.5 10000 avgt 5 1029.883 100.291 us/op
partialSortThenBitmapOf 0.5 100000 avgt 5 10472.509 832.719 us/op
partialSortThenBitmapOf 0.5 1000000 avgt 5 101144.032 16908.087 us/op
partialSortThenBitmapOf 0.5 10000000 avgt 5 958242.087 39650.946 us/op
partialSortThenBitmapOf 0.9 10000 avgt 5 1008.413 70.999 us/op
partialSortThenBitmapOf 0.9 100000 avgt 5 10458.34 600.416 us/op
partialSortThenBitmapOf 0.9 1000000 avgt 5 103945.644 2026.26 us/op
partialSortThenBitmapOf 0.9 10000000 avgt 5 1065638.269 102257.059 us/op
setupCost 0.1 10000 avgt 5 6.577 0.121 us/op
setupCost 0.1 100000 avgt 5 61.378 24.113 us/op
setupCost 0.1 1000000 avgt 5 1021.588 536.68 us/op
setupCost 0.1 10000000 avgt 5 13182.341 196.773 us/op
setupCost 0.5 10000 avgt 5 7.139 2.216 us/op
setupCost 0.5 100000 avgt 5 60.847 23.395 us/op
setupCost 0.5 1000000 avgt 5 800.888 14.711 us/op
setupCost 0.5 10000000 avgt 5 13431.625 553.44 us/op
setupCost 0.9 10000 avgt 5 6.599 0.09 us/op
setupCost 0.9 100000 avgt 5 60.946 22.511 us/op
setupCost 0.9 1000000 avgt 5 813.445 4.896 us/op
setupCost 0.9 10000000 avgt 5 13374.943 349.314 us/op
sortThenBitmapOf 0.1 10000 avgt 5 636.23 13.423 us/op
sortThenBitmapOf 0.1 100000 avgt 5 7411.756 174.264 us/op
sortThenBitmapOf 0.1 1000000 avgt 5 92299.305 3651.161 us/op
sortThenBitmapOf 0.1 10000000 avgt 5 1096374.443 162575.234 us/op
sortThenBitmapOf 0.5 10000 avgt 5 634.957 47.447 us/op
sortThenBitmapOf 0.5 100000 avgt 5 7939.074 409.328 us/op
sortThenBitmapOf 0.5 1000000 avgt 5 93505.427 5409.749 us/op
sortThenBitmapOf 0.5 10000000 avgt 5 1147933.592 57485.51 us/op
sortThenBitmapOf 0.9 10000 avgt 5 661.072 6.717 us/op
sortThenBitmapOf 0.9 100000 avgt 5 7915.506 356.148 us/op
sortThenBitmapOf 0.9 1000000 avgt 5 93403.343 5454.583 us/op
sortThenBitmapOf 0.9 10000000 avgt 5 1095960.734 85753.917 us/op

It looks like there are good performance gains available here, but these things tend to depend on particular data sets. I would be interested in hearing from anyone who has tried to use this class in a real application.

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