CPU Time Sampler Tester

Basic tester for the CPU Time Sampler, that runs JFR in different configurations, with different GCs with the renaissance suite.

This will take long but emits a csv file (default results.csv) with the results and helps to check if the CPU Time Sampler is working as expected, i.e. not crashing or producing less events than the normal JFR sampler.

Features

• Profile with different JFR chunk sizes
• ... different heap sizes
• ... different GCs
• ... different samplers (the standard JFR and the CPU Time Sampler)
• ... different JFR recording durations
• ... different renaissance iteration numbers

This allows you to stress test the samplers.

Usage

This requires that java is actually a build from openjdk/jdk#20752 (https://github.com/parttimenerd/jdk/tree/parttimenerd_cooperative_cpu_time_sampler or https://github.com/parttimenerd/jdk/tree/parttimenerd_jfr_cpu_time_sampler4)

mvn package
java -jar target/basic-profiler-tests.jar

I typically run the tests like this:

java -jar target/basic-profiler-tests.jar --csv-file log.csv --append-csv --runs=-1 --verbose=ALL_WITH_TIMESTAMPS --random-benchmark-order --random-config-order

Options via --help:

Usage: ctest [-ahV] [--keep-jfr] [--random-benchmark-order]
             [--random-config-order] [--csv-file=<csvFile>] [-i=<iterations>]
             [--java=<java>] [--jfr-folder=<jfrFolder>] [--runs=<runs>]
             [-v=<verbose>] [-b=<benchmarks>[,<benchmarks>...]]...
             [-d=<jfrDurations>]... [-g=<gcs>[,<gcs>...]]... [-H=<heapSizes>[,
             <heapSizes>...]]... [-m=<maxChunkSizes>[,<maxChunkSizes>...]]...
             [-s=<samplers>[,<samplers>...]]...
Starts a JFR recording and tests it with different scenarios.
  -a, --append-csv           Append to the CSV file instead of overwriting it.
  -b, --benchmark=<benchmarks>[,<benchmarks>...]
                             The benchmarks to run. Possible values: RENAISSANCE
      --csv-file=<csvFile>   The output file to write the results to.
  -d, --durations=<jfrDurations>
                             Duration of the recordings, recordings will be
                               repeated till the benchmark ends. Possible
                               values: FULL, SHORT, MEDIUM, TINY, RANDOM,
                               RANDOM_SHORT
  -g, --gcs=<gcs>[,<gcs>...] The garbage collectors to use. Possible values:
                               G1, ZGC, SERIAL, PARALLEL
  -h, --help                 Show this help message and exit.
  -H, --heap-sizes=<heapSizes>[,<heapSizes>...]
                             The heap sizes to use. Possible values: DEFAULT
  -i, --iterations=<iterations>
                             The number of iterations to run the benchmarks
                               (for renaisance and dacapo, -1 for default).
      --java=<java>          The java executable to use.
      --jfr-folder=<jfrFolder>
                             The folder to write the JFR files to.
      --keep-jfr             The JFR file to write the recordings to.
  -m, --max-chunk-sizes=<maxChunkSizes>[,<maxChunkSizes>...]
                             The max chunk sizes to use. Possible values:
                               ONE_MB, DEFAULT
      --random-benchmark-order
                             Randomize the order of the renaissance benchmarks
      --random-config-order  Randomize the order of the configs
      --runs=<runs>          The number of runs of the whole suite, -1 for
                               infinite runs.
  -s, --samplers=<samplers>[,<samplers>...]
                             The sampler configs to use. Possible values:
                               CPU_ONLY, OTHER_SAMPLER, WITH_OTHER_SAMPLER,
                               FULL_PROFILE
  -v, --verbose=<verbose>    Print all program outputs
  -V, --version              Print version information and exit.

License

GPLv2, Copyright 2025 SAP SE or an SAP affiliate company, Johannes Bechberger and contributors