RFR: 8278282: G1: Log basic statistics for evacuation failure [v3]

[Albert Mingkun Yang]

On Wed, 22 Dec 2021 02:33:37 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> The original pr is at #6763 , which should be retired as we have decided to adjust part of optimization solution for evacuation failure (see #6627 for details), so the log will be adjusted accordiingly.
>> The basic log related to evacuation failed will looks like below based on this patch.
>> 
>> 
>> [13.126s][debug][gc,phases] GC(0)       Restore Retained Regions (ms): Min:  0.0, Avg: 197.4, Max: 1579.1, Diff: 1579.1, Sum: 1579.1, Workers: 8
>> [13.126s][debug][gc,phases] GC(0)         Evacuation Failure Regions:    Min: 1, Avg:  1.0, Max: 1, Diff: 0, Sum: 1, Workers: 1
>
> Hamlin Li has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:
> 
>  - Merge branch 'master' into log-evac-failure-region-num
>  - Fix test
>  - Initial commit

Just a minor comment.

src/hotspot/share/gc/g1/g1GCPhaseTimes.cpp line 135:

> 133:   _gc_par_phases[MergePSS]->create_thread_work_items("LAB Undo Waste", MergePSSLABUndoWasteBytes);
> 134: 
> 135:   _gc_par_phases[RestoreRetainedRegions]->create_thread_work_items("Evacuation Failure Regions:", RestoreRetainedRegionsNum);

Based on the surrounding naming conventions, `RestoreRetainedRegionsNum` should probably be sth like `RestoreRetainedRegionsNumEvacFailRegions` or just the suffix `NumEvacFailRegions`.

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Marked as reviewed by ayang (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/6860