RFR: Changes to simplify MU accounting

[Kelvin Nilsen]

On Tue, 9 May 2023 01:56:25 GMT, Y. Srinivas Ramakrishna <ysr at openjdk.org> wrote:

>> This represents a small part of the expand-old-on-demand branch.  By itself, this may result in some performance regression because we no longer use MU (mutator utilization) reports to guide generation sizing decisions.  On the other hand, the guidance provided by MU metrics does not seem to be a very accurate predictor of ideal generation sizes.
>
> src/hotspot/share/gc/shenandoah/shenandoahControlThread.cpp line 506:
> 
>> 504:       msg = (generation == YOUNG) ? "At end of Concurrent Young GC" :
>> 505:                                     "At end of Concurrent Bootstrap GC";
>> 506:       // We only record GC results if GC was successful
> 
> Can this section on MMU tracking be moved into `SCT::service_concurrent_cycle(ShenandoahHeap*, ShenandoahGeneration*, GCCause&, bool bootstrap)` at (just after) line 728 below?
> 
> That would be consistent with doing the corresponding old gen work in `SCT::service_cocnurrent_old_cycle()` as you've done below.

Thanks.  I'm moving this code as suggested on the expand-old-on-demand branch.  I'm going to close this PR without integration.

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/274#discussion_r1202804935