RFR: 8337511: Implement JEP 404: Generational Shenandoah (Experimental) [v7]

[Aleksey Shipilev]

On Tue, 19 Nov 2024 19:54:45 GMT, William Kemper <wkemper at openjdk.org> wrote:

>> src/hotspot/share/gc/shenandoah/shenandoahHeap.inline.hpp line 276:
>> 
>>> 274:     log_info(gc)("GC cancellation took %.3fs", cancel_time);
>>> 275:     _cancel_requested_time = 0;
>>> 276:   }
>> 
>> Do we need this? Is this useful?
>
> We could log this at debug? I believe it is useful because this time (currently) is not accounted for in the heuristic's notion of 'cycle time'.

Yeah, `gc=debug` would be okay for this.

>> src/hotspot/share/gc/shenandoah/shenandoahPhaseTimings.cpp line 193:
>> 
>>> 191:     Phase phase = Phase(pi);
>>> 192:     if (is_worker_phase(phase)) {
>>> 193:       double sum = uninitialized();
>> 
>> I think you can avoid changing this method to limit the churn.
>
> Hmm, I find the version in the PR much more readable. How about we upstream these changes separately?

Yes, let's do that, if you have cycles.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21273#discussion_r1852533117
PR Review Comment: https://git.openjdk.org/jdk/pull/21273#discussion_r1852533548