MethodDataSharing.java

package redhat.app.services.benchmark;

import java.util.concurrent.TimeUnit;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.CompilerControl;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;

/**
 * This benchmark should be used with the following JVM options to tune the tier compilation level:
 * -XX:TieredStopAtLevel=
 *
 */
@State(Scope.Benchmark)
@Fork(2)
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@Measurement(iterations = 10, time = 1, timeUnit = TimeUnit.SECONDS)
@Warmup(iterations = 10, time = 1, timeUnit = TimeUnit.SECONDS)
public class MethodDataSharing {

   @Benchmark
   public void doFoo() {
      foo(1000, true);
   }


   @CompilerControl(CompilerControl.Mode.DONT_INLINE)
   private static int foo(int count, boolean countAll) {
      int total = 0;
      for (int i = 0; i < count; i++) {
         if (countAll) {
           total++;
         }
      }
      return total;
   }
}

$ java -jar target/benchmark.jar MethodDataSharing -t 2 --jvmArgs="-XX:TieredStopAtLevel=3" -prof perfasm

Benchmark                    Mode  Cnt      Score      Error  Units
MethodDataSharing.doFoo      avgt   20  15414.012 ± 1616.955  ns/op

lstopo shows:

$ numactl --physcpubind 0,8 java -jar target/benchmark.jar MethodDataSharing -t 2 --jvmArgs="-XX:TieredStopAtLevel=3" -prof perfasm

Benchmark                    Mode  Cnt      Score      Error  Units
MethodDataSharing.doFoo      avgt   20  16427.929 ± 1475.128  ns/op

while keeping everything on the same socket

$ numactl --physcpubind 0,1 java -jar target/benchmark.jar MethodDataSharing -t 2 --jvmArgs="-XX:TieredStopAtLevel=3" -prof perfasm

Benchmark                Mode  Cnt     Score     Error  Units
MethodDataSharing.doFoo  avgt   20  8662.030 ± 731.919  ns/op

and perf analysis shows , in the more costly case:

....[Hottest Region 1]..............................................................................
c1, level 3, redhat.app.services.benchmark.MethodDataSharing::foo, version 2, compile id 719 

                0x00007fb68cf14168:   mov    $0x0,%edi
          ╭     0x00007fb68cf1416d:   jmp    0x00007fb68cf141f7           ;*iload_3 {reexecute=0 rethrow=0 return_oop=0}
          │                                                               ; - redhat.app.services.benchmark.MethodDataSharing::foo@4 (line 39)
          │     0x00007fb68cf14172:   nopw   0x0(%rax,%rax,1)
   0.03%  │     0x00007fb68cf14178:   cmp    $0x0,%edx
          │     0x00007fb68cf1417b:   movabs $0x7fb6104de900,%rbx         ;   {metadata(method data for {method} {0x00007fb6104783c8} 'foo' '(IZ)I' in 'redhat/app/services/benchmark/MethodDataSharing')}
          │     0x00007fb68cf14185:   movabs $0x158,%rcx
          │╭    0x00007fb68cf1418f:   je     0x00007fb68cf1419f
          ││    0x00007fb68cf14195:   movabs $0x168,%rcx
          │↘    0x00007fb68cf1419f:   mov    (%rbx,%rcx,1),%r8
   9.41%  │     0x00007fb68cf141a3:   lea    0x1(%r8),%r8
          │     0x00007fb68cf141a7:   mov    %r8,(%rbx,%rcx,1)
   0.11%  │ ╭   0x00007fb68cf141ab:   je     0x00007fb68cf141b3           ;*ifeq {reexecute=0 rethrow=0 return_oop=0}
          │ │                                                             ; - redhat.app.services.benchmark.MethodDataSharing::foo@10 (line 40)
          │ │   0x00007fb68cf141b1:   inc    %edi
          │ ↘   0x00007fb68cf141b3:   inc    %eax
          │     0x00007fb68cf141b5:   movabs $0x7fb6104de900,%rbx         ;   {metadata(method data for {method} {0x00007fb6104783c8} 'foo' '(IZ)I' in 'redhat/app/services/benchmark/MethodDataSharing')}
          │     0x00007fb68cf141bf:   mov    0xf8(%rbx),%ecx
  17.60%  │     0x00007fb68cf141c5:   add    $0x2,%ecx
   0.01%  │     0x00007fb68cf141c8:   mov    %ecx,0xf8(%rbx)
   0.02%  │     0x00007fb68cf141ce:   and    $0x3ffe,%ecx
   0.05%  │     0x00007fb68cf141d4:   cmp    $0x0,%ecx
          │     0x00007fb68cf141d7:   je     0x00007fb68cf14266           ;*goto {reexecute=0 rethrow=0 return_oop=0}
          │                                                               ; - redhat.app.services.benchmark.MethodDataSharing::foo@19 (line 39)
          │     0x00007fb68cf141dd:   mov    0x458(%r15),%r10             ; ImmutableOopMap {}
          │                                                               ;*goto {reexecute=1 rethrow=0 return_oop=0}
          │                                                               ; - (reexecute) redhat.app.services.benchmark.MethodDataSharing::foo@19 (line 39)
   0.03%  │     0x00007fb68cf141e4:   test   %eax,(%r10)                  ;   {poll}
          │     0x00007fb68cf141e7:   movabs $0x7fb6104de900,%rbx         ;   {metadata(method data for {method} {0x00007fb6104783c8} 'foo' '(IZ)I' in 'redhat/app/services/benchmark/MethodDataSharing')}
          │     0x00007fb68cf141f1:   incl   0x178(%rbx)                  ;*goto {reexecute=0 rethrow=0 return_oop=0}
          │                                                               ; - redhat.app.services.benchmark.MethodDataSharing::foo@19 (line 39)
  40.64%  ↘     0x00007fb68cf141f7:   cmp    %esi,%eax
                0x00007fb68cf141f9:   movabs $0x7fb6104de900,%rbx         ;   {metadata(method data for {method} {0x00007fb6104783c8} 'foo' '(IZ)I' in 'redhat/app/services/benchmark/MethodDataSharing')}
                0x00007fb68cf14203:   movabs $0x148,%rcx
             ╭  0x00007fb68cf1420d:   jl     0x00007fb68cf1421d
             │  0x00007fb68cf14213:   movabs $0x138,%rcx
   0.01%     ↘  0x00007fb68cf1421d:   mov    (%rbx,%rcx,1),%r8
  30.63%        0x00007fb68cf14221:   lea    0x1(%r8),%r8
   0.03%        0x00007fb68cf14225:   mov    %r8,(%rbx,%rcx,1)
   0.04%        0x00007fb68cf14229:   jl     0x00007fb68cf14178           ;*if_icmpge {reexecute=0 rethrow=0 return_oop=0}
                                                                          ; - redhat.app.services.benchmark.MethodDataSharing::foo@6 (line 39)
....................................................................................................
  67.86%  <total for region 1>

which shows several metadata(method data for {method} {0x00007fb6104783c8} comments, which refer to the method data object starting at 0x7fb6104de900, which contains few counters in.