How to use Java 12's Microbenchmark Suite?

Question

According to JEP 230: Microbenchmark Suite, there exists a microbenchmark suite built-in to Java 12. The JEP explains that it's basically JMH, but without needing to explicitly depend on it using Maven/Gradle. However, it doesn't specify how to go about accessing the classes/annotations that belong to the suite to perform a benchmark.

My questions are:

• Is there a specific Java module that I need to require in my module-info.java to be able to use this suite?
• What package(s) are the classes/annotations of this suite located in?
• Are there any major differences between this suite and JMH?

Answer 1

Your interpretation is incorrect. The JEP says:

Add a basic suite of microbenchmarks to the JDK source code, and make it easy for developers to run existing microbenchmarks and create new ones.

i.e. this is not necessarily something that makes it into a JDK distribution, just something that is added to the source code repository to make it easier to run benchmarks on JDK code. Though, to be fair, the fact that it's listed as one of the JDK 12 'features' seems a tad misleading.

The benchmarks can be run by using the OpenJDK build system. Once you have cloned the OpenJDK source code from https://github.com/openjdk/jdk (or another repository that includes the JEP), you can run benchmarks e.g. by using:

make test TEST="micro:java.lang.reflect"

Benchmarks are located in the \test\micro\ directory. See also the documentation: https://github.com/openjdk/jdk/blob/master/doc/testing.md#microbenchmarks

Also, this requires you to specify JMH and it's dependencies when generating a build configuration:

bash configure --with-jmh="/path/to/jmh/jars"

The specified path should point to a directory containing the JMH jars. Required jars are: commons-math3, jmh-core, jmh-generator-annprocess, and jopt-simple.