Usage of JMH tasks

Only execute specific benchmark(s) (wildcards are added before and after):

../gradlew jmh --include="(BenchmarkPrimary|OtherBench)"

If you want to specify the wildcards yourself, you can pass the full regexp:

../gradlew jmh --fullInclude=.*MyBenchmark.*

Specify extra profilers:

../gradlew jmh --profilers="gc,stack"

Prominent profilers (for full list call jmhProfilers task):

• comp - JitCompilations, tune your iterations
• stack - which methods used most time
• gc - print garbage collection stats
• hs_thr - thread usage

Change report format from JSON to one of [CSV, JSON, NONE, SCSV, TEXT]:

./gradlew jmh --format=csv

Specify JVM arguments:

../gradlew jmh --jvmArgs="-Dtest.cluster=local"

Run in verification mode (execute benchmarks with minimum of fork/warmup-/benchmark-iterations):

../gradlew jmh --verify=true

Comparing with the baseline

If you wish you run two sets of benchmarks, one for the current change and another one for the "baseline", there is an additional task jmhBaseline that will use the latest release:

../gradlew jmh jmhBaseline --include=MyBenchmark

Resources

• http://tutorials.jenkov.com/java-performance/jmh.html (Introduction)
• http://hg.openjdk.java.net/code-tools/jmh/file/tip/jmh-samples/src/main/java/org/openjdk/jmh/samples/ (Samples)