RFR: 8339197: GenShen: Adding Generation and Evacuation Information JFR Logging [v3]

[Kelvin Nilsen]

On Thu, 29 Aug 2024 00:03:56 GMT, Kelvin Nilsen <kdnilsen at openjdk.org> wrote:

>> src/hotspot/share/gc/shenandoah/heuristics/shenandoahGenerationalHeuristics.cpp line 233:
>> 
>>> 231:     evacInfo.set_regions_freed(free_regions);
>>> 232: 
>>> 233:     ShenandoahTracer().report_evacuation_info(&evacInfo);
>> 
>> After we chatted, I thought of one other detail that would be nice to gather in this evacInfo event: regions to be promoted in place.  Associated with this detail, would be nice to know:
>> 1. how many regions
>> 2. how much garbage is known to exist within these regions
>> 3. how much free memory is known to exist within these regions
>> Same for humongous regions promoted in place.
>> 
>> See humongous_regions_promoted, regular_regions_promoted_in_place, regular_regions_promoted_usage.   You might need to add another bookkeeping variable to count regular_regions_promoted_live, tracking regular_regions_promoted_usage.
>
> for humongous_regions_promoted, less important to distinguish used and free, because that memory is "off limits" to allocators.

Looks good.

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/489#discussion_r1739210062