RFR: 8144: Add rule to detect GC Inverted Parallelism [v2]

[Marcus Hirt]

On Mon, 20 Nov 2023 18:24:06 GMT, Alex Macdonald <aptmac at openjdk.org> wrote:

>> This PR addresses JMC-8144 [[0]](https://bugs.openjdk.org/browse/JMC-8144). There is a GC log analysis tool called Garbagecat [[1]](https://github.com/mgm3746/garbagecat/tree/main), which operates on GC logs and identifies performance issues and suggests potential solutions (similar to our automated analysis page). One metric Garbagecat flags is **"inverted parallelism"**, which takes a look at the sys+usr time of a parallel GC and compares it against the real (wall) time. If the parallelism is low, this can indicate that the parallel gc is operating at the efficiency of serial gc, and there could be room for improvement. This GC time information is now included in the jdk.GCCPUTime event added in JDK20+.
>> 
>> This PR requires support for the jdk.GCCPUTime event [[2]](https://bugs.openjdk.org/browse/JDK-8291753), so it also doubles as a PR towards JMC-7895 [[3]](https://bugs.openjdk.org/browse/JMC-7895).
>> 
>> [0] https://bugs.openjdk.org/browse/JMC-8144
>> [1] https://github.com/mgm3746/garbagecat/tree/main
>> [2] https://bugs.openjdk.org/browse/JDK-8291753
>> [3] https://bugs.openjdk.org/browse/JMC-7895
>
> Alex Macdonald has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains two commits:
> 
>  - Add jdk21 recordings for rules.jdk test
>  - 8144: Add rule to detect GC Inverted Parallelism

Marked as reviewed by hirt (Lead).

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PR Review: https://git.openjdk.org/jmc/pull/528#pullrequestreview-1757920376