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: 10 iterations, 200 ms 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.SortBenchmark.sortCopy
+
+# Run progress: 0.00% complete, ETA 00:00:07
+# Fork: 1 of 1
+# Warmup Iteration   1: 9.502 us/op
+# Warmup Iteration   2: 7.662 us/op
+# Warmup Iteration   3: 4.997 us/op
+# Warmup Iteration   4: 4.586 us/op
+# Warmup Iteration   5: 4.362 us/op
+# Warmup Iteration   6: 6.260 us/op
+# Warmup Iteration   7: 6.648 us/op
+# Warmup Iteration   8: 5.701 us/op
+# Warmup Iteration   9: 4.546 us/op
+# Warmup Iteration  10: 4.359 us/op
+Iteration   1: 5.683 us/op
+Iteration   2: 6.121 us/op
+Iteration   3: 4.753 us/op
+Iteration   4: 4.963 us/op
+Iteration   5: 5.553 us/op
+
+
+Result "com.ankurm.jmhbasics.SortBenchmark.sortCopy":
+  5.414 ±(99.9%) 2.138 us/op [Average]
+  (min, avg, max) = (4.753, 5.414, 6.121), stdev = 0.555
+  CI (99.9%): [3.277, 7.552] (assumes normal distribution)
+
+
+# Run complete. Total time: 00:00:07
+
+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
+SortBenchmark.sortCopy  avgt    5  5.414 ± 2.138  us/op