RFR: 8256265: G1: Improve parallelism in regions that failed evacuation [v9]

[Thomas Schatzl]

On Tue, 1 Mar 2022 10:01:56 GMT, Hamlin Li <mli at openjdk.org> wrote:

> > 4. I don't understand why `RemoveSelfForwardChunksPerRegion` is inside `...WorkItems`. #chunks_per_region should be a constant shared by all workers. Its siblings are worker-local stats, which are sensible to have inside `...WorkItems`.
> 
> Thanks, I will update the patch as you suggested except the last one. In fact, I do have the same question as you, but IMO currently G1GCPhaseTimes supports time and work item, and work item only supports in per thread style.

Sorry, I did not catch this question immediately: `RemoveSelfForwardChunksPerRegion` does not need to be stored within this part of the log. It could be included in a message like for other `WorkerThreads` invocations like in `HeapRegionManager::rebuild_free_list` instead of putting it into `G1GCPhaseTimes`:


  log_debug(gc, ergo)("Running %s using %u workers for removing self forwards with %u chunks per region",
                      task.name(), num_workers, chunk_size);


Thomas

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PR: https://git.openjdk.java.net/jdk/pull/7047