RFR: 8350314: Shenandoah: Capture thread state sync times in GC timings [v6]

[Xiaolong Peng]

On Wed, 26 Feb 2025 19:42:10 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Xiaolong Peng has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove trailing whitespace
>
> src/hotspot/share/gc/shenandoah/shenandoahConcurrentGC.cpp line 693:
> 
>> 691: 
>> 692:   {
>> 693:     ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_propagate_gc_state);
> 
> Here and later, I messed up my suggestion. I think these should be `ShenandoahTimingsTracker`, not `ShenandoahGCPhase`. `ShenandoahGCPhase` does more stuff we don't need. `ShenandoahTimingsTracker` does only the basic stuff.

Thanks for pointing out, I'll update it and move them to `ShenandoahTimingsTracker` and test it again.

> src/hotspot/share/gc/shenandoah/shenandoahDegeneratedGC.cpp line 86:
> 
>> 84:   op_degenerated();
>> 85:   heap->set_degenerated_gc_in_progress(false);
>> 86:   {
> 
> A bit sad we need to do this due to `op_degenerated` early returns, but fine.

Yeah, this part is not very clean due to op_degenerated early returns.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23759#discussion_r1972349321
PR Review Comment: https://git.openjdk.org/jdk/pull/23759#discussion_r1972347797