jmh-basics: JMH tutorial module (dead-code elimination, Blackhole, constant folding, warmup/forks, state scopes, -prof gc)

Eight benchmark/demo classes, a deterministic test suite, and 12 captured output files generated by scripts/run-all.sh on JDK 25.0.5 (Temurin) with JMH 1.37. Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_017ic4b6Fj2JNt7dRev4pZPe
2026-11-08 18:31:11 +00:00
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+# 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: 5 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.SumBenchmark.sum
+# Parameters: (size = 10)
+
+# Run progress: 0.00% complete, ETA 00:00:24
+# Fork: 1 of 1
+# Warmup Iteration   1: 11.152 ns/op
+# Warmup Iteration   2: 9.349 ns/op
+# Warmup Iteration   3: 11.239 ns/op
+Iteration   1: 11.426 ns/op
+Iteration   2: 11.575 ns/op
+Iteration   3: 11.528 ns/op
+Iteration   4: 8.986 ns/op
+Iteration   5: 10.091 ns/op
+
+
+Result "com.ankurm.jmhbasics.SumBenchmark.sum":
+  10.721 ±(99.9%) 4.427 ns/op [Average]
+  (min, avg, max) = (8.986, 10.721, 11.575), stdev = 1.150
+  CI (99.9%): [6.294, 15.149] (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: 5 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.SumBenchmark.sum
+# Parameters: (size = 1000)
+
+# Run progress: 33.33% complete, ETA 00:00:16
+# Fork: 1 of 1
+# Warmup Iteration   1: 72.906 ns/op
+# Warmup Iteration   2: 61.956 ns/op
+# Warmup Iteration   3: 60.801 ns/op
+Iteration   1: 53.346 ns/op
+Iteration   2: 57.255 ns/op
+Iteration   3: 52.866 ns/op
+Iteration   4: 54.738 ns/op
+Iteration   5: 54.117 ns/op
+
+
+Result "com.ankurm.jmhbasics.SumBenchmark.sum":
+  54.465 ±(99.9%) 6.611 ns/op [Average]
+  (min, avg, max) = (52.866, 54.465, 57.255), stdev = 1.717
+  CI (99.9%): [47.854, 61.075] (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: 5 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.SumBenchmark.sum
+# Parameters: (size = 100000)
+
+# Run progress: 66.67% complete, ETA 00:00:08
+# Fork: 1 of 1
+# Warmup Iteration   1: 8474.836 ns/op
+# Warmup Iteration   2: 7431.944 ns/op
+# Warmup Iteration   3: 7347.101 ns/op
+Iteration   1: 7377.289 ns/op
+Iteration   2: 7499.047 ns/op
+Iteration   3: 7046.908 ns/op
+Iteration   4: 7454.035 ns/op
+Iteration   5: 7662.632 ns/op
+
+
+Result "com.ankurm.jmhbasics.SumBenchmark.sum":
+  7407.982 ±(99.9%) 875.072 ns/op [Average]
+  (min, avg, max) = (7046.908, 7407.982, 7662.632), stdev = 227.254
+  CI (99.9%): [6532.910, 8283.055] (assumes normal distribution)
+
+
+# Run complete. Total time: 00:00:25
+
+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         (size)  Mode  Cnt     Score     Error  Units
+SumBenchmark.sum      10  avgt    5    10.721 ±   4.427  ns/op
+SumBenchmark.sum    1000  avgt    5    54.465 ±   6.611  ns/op
+SumBenchmark.sum  100000  avgt    5  7407.982 ± 875.072  ns/op