RFR: 8315149: Add hsperf counters for CPU time of internal GC threads [v27]

[Jonathan Joo]

On Wed, 11 Oct 2023 23:23:11 GMT, Man Cao <manc at openjdk.org> wrote:

>> Jonathan Joo has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   add comment and change if defined to ifdef
>
> src/hotspot/share/gc/shared/collectedHeap.cpp line 298:
> 
>> 296:   NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
>> 297: 
>> 298:   if (UsePerfData && os::is_thread_cpu_time_supported()) {
> 
> This condition should be a nested if inside `if (UsePerfData)`:
> 
> 
> if (os::is_thread_cpu_time_supported()) {
>   _total_cpu_time = ...;
>   _perf_parallel_worker_threads_cpu_time = ...;
> }
> 
> Otherwise `_perf_gc_cause` and `_perf_gc_lastcause` could be broken.

Ah yes, good catch!

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PR Review Comment: https://git.openjdk.org/jdk/pull/15082#discussion_r1357552757