# JMH version: 1.37 # VM version: JDK 25.0.5, OpenJDK 64-Bit Server VM, 25.0.5+8-LTS # VM invoker: /tmp/tools/jdk-25.0.5+8/bin/java # Blackhole mode: compiler (auto-detected, use -Djmh.blackhole.autoDetect=false to disable) # Warmup: 3 iterations, 1 s each # Measurement: 3 iterations, 1 s each # Timeout: 10 min per iteration # Threads: 1 thread, will synchronize iterations # Benchmark mode: Average time, time/op # Benchmark: com.ankurm.jmhbasics.AllocationBenchmark.arrayEscapes # Run progress: 0.00% complete, ETA 00:00:18 # Fork: 1 of 1 # Warmup Iteration 1: 7.135 ns/op # Warmup Iteration 2: 5.665 ns/op # Warmup Iteration 3: 5.072 ns/op Iteration 1: 5.345 ns/op gc.alloc.rate: 5707.275 MB/sec gc.alloc.rate.norm: 32.000 B/op gc.count: 18.000 counts gc.time: 21.000 ms Iteration 2: 5.649 ns/op gc.alloc.rate: 5400.357 MB/sec gc.alloc.rate.norm: 32.000 B/op gc.count: 18.000 counts gc.time: 22.000 ms Iteration 3: 5.596 ns/op gc.alloc.rate: 5448.664 MB/sec gc.alloc.rate.norm: 32.000 B/op gc.count: 17.000 counts gc.time: 22.000 ms Result "com.ankurm.jmhbasics.AllocationBenchmark.arrayEscapes": 5.530 ±(99.9%) 2.966 ns/op [Average] (min, avg, max) = (5.345, 5.530, 5.649), stdev = 0.163 CI (99.9%): [2.564, 8.496] (assumes normal distribution) Secondary result "com.ankurm.jmhbasics.AllocationBenchmark.arrayEscapes:gc.alloc.rate": 5518.765 ±(99.9%) 3010.780 MB/sec [Average] (min, avg, max) = (5400.357, 5518.765, 5707.275), stdev = 165.031 CI (99.9%): [2507.986, 8529.545] (assumes normal distribution) Secondary result "com.ankurm.jmhbasics.AllocationBenchmark.arrayEscapes:gc.alloc.rate.norm": 32.000 ±(99.9%) 0.001 B/op [Average] (min, avg, max) = (32.000, 32.000, 32.000), stdev = 0.001 CI (99.9%): [32.000, 32.000] (assumes normal distribution) Secondary result "com.ankurm.jmhbasics.AllocationBenchmark.arrayEscapes:gc.count": 53.000 ±(99.9%) 0.001 counts [Sum] (min, avg, max) = (17.000, 17.667, 18.000), stdev = 0.577 CI (99.9%): [53.000, 53.000] (assumes normal distribution) Secondary result "com.ankurm.jmhbasics.AllocationBenchmark.arrayEscapes:gc.time": 65.000 ±(99.9%) 0.001 ms [Sum] (min, avg, max) = (21.000, 21.667, 22.000), stdev = 0.577 CI (99.9%): [65.000, 65.000] (assumes normal distribution) # JMH version: 1.37 # VM version: JDK 25.0.5, OpenJDK 64-Bit Server VM, 25.0.5+8-LTS # VM invoker: /tmp/tools/jdk-25.0.5+8/bin/java # Blackhole mode: compiler (auto-detected, use -Djmh.blackhole.autoDetect=false to disable) # Warmup: 3 iterations, 1 s each # Measurement: 3 iterations, 1 s each # Timeout: 10 min per iteration # Threads: 1 thread, will synchronize iterations # Benchmark mode: Average time, time/op # Benchmark: com.ankurm.jmhbasics.AllocationBenchmark.doesNotEscape # Run progress: 33.33% complete, ETA 00:00:12 # Fork: 1 of 1 # Warmup Iteration 1: 0.664 ns/op # Warmup Iteration 2: 0.732 ns/op # Warmup Iteration 3: 0.754 ns/op Iteration 1: 1.044 ns/op gc.alloc.rate: 0.007 MB/sec gc.alloc.rate.norm: ≈ 10⁻⁵ B/op gc.count: ≈ 0 counts Iteration 2: 0.849 ns/op gc.alloc.rate: 0.007 MB/sec gc.alloc.rate.norm: ≈ 10⁻⁵ B/op gc.count: ≈ 0 counts Iteration 3: 0.774 ns/op gc.alloc.rate: 0.007 MB/sec gc.alloc.rate.norm: ≈ 10⁻⁵ B/op gc.count: ≈ 0 counts Result "com.ankurm.jmhbasics.AllocationBenchmark.doesNotEscape": 0.889 ±(99.9%) 2.544 ns/op [Average] (min, avg, max) = (0.774, 0.889, 1.044), stdev = 0.139 CI (99.9%): [≈ 0, 3.432] (assumes normal distribution) Secondary result "com.ankurm.jmhbasics.AllocationBenchmark.doesNotEscape:gc.alloc.rate": 0.007 ±(99.9%) 0.001 MB/sec [Average] (min, avg, max) = (0.007, 0.007, 0.007), stdev = 0.001 CI (99.9%): [0.007, 0.007] (assumes normal distribution) Secondary result "com.ankurm.jmhbasics.AllocationBenchmark.doesNotEscape:gc.alloc.rate.norm": ≈ 10⁻⁵ B/op Secondary result "com.ankurm.jmhbasics.AllocationBenchmark.doesNotEscape:gc.count": ≈ 0 counts # JMH version: 1.37 # VM version: JDK 25.0.5, OpenJDK 64-Bit Server VM, 25.0.5+8-LTS # VM invoker: /tmp/tools/jdk-25.0.5+8/bin/java # Blackhole mode: compiler (auto-detected, use -Djmh.blackhole.autoDetect=false to disable) # Warmup: 3 iterations, 1 s each # Measurement: 3 iterations, 1 s each # Timeout: 10 min per iteration # Threads: 1 thread, will synchronize iterations # Benchmark mode: Average time, time/op # Benchmark: com.ankurm.jmhbasics.AllocationBenchmark.escapes # Run progress: 66.67% complete, ETA 00:00:06 # Fork: 1 of 1 # Warmup Iteration 1: 6.088 ns/op # Warmup Iteration 2: 4.657 ns/op # Warmup Iteration 3: 4.507 ns/op Iteration 1: 4.959 ns/op gc.alloc.rate: 4609.827 MB/sec gc.alloc.rate.norm: 24.000 B/op gc.count: 16.000 counts gc.time: 20.000 ms Iteration 2: 4.719 ns/op gc.alloc.rate: 4843.713 MB/sec gc.alloc.rate.norm: 24.000 B/op gc.count: 17.000 counts gc.time: 21.000 ms Iteration 3: 4.898 ns/op gc.alloc.rate: 4671.068 MB/sec gc.alloc.rate.norm: 24.000 B/op gc.count: 16.000 counts gc.time: 18.000 ms Result "com.ankurm.jmhbasics.AllocationBenchmark.escapes": 4.859 ±(99.9%) 2.271 ns/op [Average] (min, avg, max) = (4.719, 4.859, 4.959), stdev = 0.124 CI (99.9%): [2.588, 7.130] (assumes normal distribution) Secondary result "com.ankurm.jmhbasics.AllocationBenchmark.escapes:gc.alloc.rate": 4708.203 ±(99.9%) 2212.682 MB/sec [Average] (min, avg, max) = (4609.827, 4708.203, 4843.713), stdev = 121.285 CI (99.9%): [2495.521, 6920.885] (assumes normal distribution) Secondary result "com.ankurm.jmhbasics.AllocationBenchmark.escapes:gc.alloc.rate.norm": 24.000 ±(99.9%) 0.001 B/op [Average] (min, avg, max) = (24.000, 24.000, 24.000), stdev = 0.001 CI (99.9%): [24.000, 24.000] (assumes normal distribution) Secondary result "com.ankurm.jmhbasics.AllocationBenchmark.escapes:gc.count": 49.000 ±(99.9%) 0.001 counts [Sum] (min, avg, max) = (16.000, 16.333, 17.000), stdev = 0.577 CI (99.9%): [49.000, 49.000] (assumes normal distribution) Secondary result "com.ankurm.jmhbasics.AllocationBenchmark.escapes:gc.time": 59.000 ±(99.9%) 0.001 ms [Sum] (min, avg, max) = (18.000, 19.667, 21.000), stdev = 1.528 CI (99.9%): [59.000, 59.000] (assumes normal distribution) # Run complete. Total time: 00:00:19 REMEMBER: The numbers below are just data. To gain reusable insights, you need to follow up on why the numbers are the way they are. Use profilers (see -prof, -lprof), design factorial experiments, perform baseline and negative tests that provide experimental control, make sure the benchmarking environment is safe on JVM/OS/HW level, ask for reviews from the domain experts. Do not assume the numbers tell you what you want them to tell. NOTE: Current JVM experimentally supports Compiler Blackholes, and they are in use. Please exercise extra caution when trusting the results, look into the generated code to check the benchmark still works, and factor in a small probability of new VM bugs. Additionally, while comparisons between different JVMs are already problematic, the performance difference caused by different Blackhole modes can be very significant. Please make sure you use the consistent Blackhole mode for comparisons. Benchmark Mode Cnt Score Error Units AllocationBenchmark.arrayEscapes avgt 3 5.530 ± 2.966 ns/op AllocationBenchmark.arrayEscapes:gc.alloc.rate avgt 3 5518.765 ± 3010.780 MB/sec AllocationBenchmark.arrayEscapes:gc.alloc.rate.norm avgt 3 32.000 ± 0.001 B/op AllocationBenchmark.arrayEscapes:gc.count avgt 3 53.000 counts AllocationBenchmark.arrayEscapes:gc.time avgt 3 65.000 ms AllocationBenchmark.doesNotEscape avgt 3 0.889 ± 2.544 ns/op AllocationBenchmark.doesNotEscape:gc.alloc.rate avgt 3 0.007 ± 0.001 MB/sec AllocationBenchmark.doesNotEscape:gc.alloc.rate.norm avgt 3 ≈ 10⁻⁵ B/op AllocationBenchmark.doesNotEscape:gc.count avgt 3 ≈ 0 counts AllocationBenchmark.escapes avgt 3 4.859 ± 2.271 ns/op AllocationBenchmark.escapes:gc.alloc.rate avgt 3 4708.203 ± 2212.682 MB/sec AllocationBenchmark.escapes:gc.alloc.rate.norm avgt 3 24.000 ± 0.001 B/op AllocationBenchmark.escapes:gc.count avgt 3 49.000 counts AllocationBenchmark.escapes:gc.time avgt 3 59.000 ms