JFR profiling does not report heap usage

[ashwini-mnnit]

I am trying to look in to JVM profile but the JFR is not reporting Heap usage. Is there a flag enable that ?

[mikemccand]

Hmm that's odd -- this is where we ask java to enable JFR recording: https://github.com/mikemccand/luceneutil/blob/main/src/python/benchUtil.py#L1185

And we use these settings: https://github.com/mikemccand/luceneutil/blob/main/src/python/profiling.jfc which seems to be enabling object allocation tracking.

Maybe we are missing settings to turn on JFR heap tracking?

[rmuir]

maybe. the file that ships with the JDK has a LOT of stuff enabled. When creating the .jfc file for profiling tests (which I think this derived from at one point), I disabled everything except the bare minimum, but then lowered the interval to 1ms. the idea was to give more fine-grained data but still keep low overhead. https://github.com/apache/lucene/blob/main/gradle/testing/profiling.jfc

You can look at the file shipped with the JDK if you want to see defaults. Maybe its even a better start for long-running benchmark? But I'd be careful of BOTH setting low intervals AND enabling the kitchen sink?

[ashwini-mnnit]

@rmuir , The config you shared does not help either. Is this related to JDK version ? I am using jdk21.