srcmaxim / jmh-101

Java Microbenchmark Harness example

JMH (Java Microbenchmark Harness) 101

gradle-version: 7.2
java-version: 16
shell: powershell

• test performance of Optional vs if statement
• test performance of Stream vs foreach
• check log messages of JIT compiler and GC

All tests executed in a Docker container to restrict some resources

Build a distribution:

gradle distZip
docker build -t jmh .

Run microbenchmark:

docker run --rm jmh [1]  

docker run --rm ` [2️] 
  -e "JAVA_OPTS=-XX:+PrintCompilation" `
  jmh
  
docker run --rm ` [3️]
  -v "$PWD/log:/jmh/log" `
  -e "JAVA_OPTS=-Xlog:gc*:file=log/gc.log:time,uptime,level,tags:filecount=1,filesize=100m" `
  jmh
  
docker run --rm ` [4️] 
  -v "$PWD/log:/jmh/log" `
  -e "JAVA_OPTS=-XX:+FlightRecorder -XX:StartFlightRecording=duration=2m,filename=log/flightIf.jfr" `
  jmh
docker run --rm `
  -v "$PWD/log:/jmh/log" `
  -e "JAVA_OPTS=-XX:+FlightRecorder -XX:StartFlightRecording=duration=2m,filename=log/flightOpt.jfr" `
  jmh
  
docker run --rm --cpus="1" ` [5️] 
  -v "$PWD/log:/jmh/log" `
  -e "JAVA_OPTS=-Xlog:gc*:file=log/gc.log:time,uptime,level,tags:filecount=1,filesize=100m" `
  jmh
  
docker run --rm jmh [6️] 
docker run --rm -m=1g --cpus="1" jmh        

[1️] Basic JMH run (more op/sec -- better)
[2️] Print JIT compiled methods
[3️] Print GC log
[4️] Print JVM Flight Recorder stats log/flight*.jfr to use in JDK Mission Control
[5️] Print GC log for 1 CPU workload
[6️] Compare unbounded to bounded app