RFR: 8314438: NMT: Performance benchmarks are needed to have a baseline for comparison of improvements [v3]

[Magnus Ihse Bursie]

On Tue, 26 Sep 2023 08:57:43 GMT, Afshin Zafari <azafari at openjdk.org> wrote:

>> A new benchmark for  measuring the NMT overhead in `summary` and `detail` modes.
>> The tests are run using: 
>> 
>> make CONF=debug test TEST="micro:java.util.NMTBenchmark" MICRO="RESULTS_FORMAT=json"
>> 
>> The results are written to a JSON file that can be visualized using [JMH Visualizer](https://jmh.morethan.io/).
>> 
>> ### Notes
>> A separate [issue](https://bugs.openjdk.org/browse/JDK-8316814) is created for preparing a progfram for validating and analyzing the JMH outputs.
>> Another separate [issue](https://bugs.openjdk.org/browse/JDK-8316813) is created for measuring the virtual memory tracing parts of NMT.
>
> Afshin Zafari has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains five commits:
> 
>  - Merge branch 'master' into _8314438
>  - new benchmark moved to vm/runtime folder.
>  - realloc and onlyMalloc are added.
>  - Sequential part is run only once if WITH_THREADS == 0
>  - 8314438: NMT: Performance benchmarks are needed to have a baseline for comparison of improvements

Build changed trivially good.

Should there not be a label to alert NMT folks for reviewing?

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Marked as reviewed by ihse (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/15563#pullrequestreview-1643858692