Integrated: 8301116: Parallelize TLAB resizing in G1

[Thomas Schatzl]

On Wed, 1 Feb 2023 10:34:36 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

> Hi all,
> 
>   can I get reviews for this change that moves TLAB resizing into the second parallel post evacuation phase?
> 
> The change is fairly straightforward except maybe for the following:
> * there is a new claimer for `JavaThreads` because the `Threads::possibly_parallel_threads_do` method to parallelize does not work well with very little per-thread work. Actually with a moderate amount of threads (~20) performance would already be many times slower than doing things serially.
> * moving the TLAB resizing out of `G1CollectedHeap::prepare_tlabs_for_mutator` made that method and the enclosing timing a bit obsolete, so I repurposed it as a "do preparatory work for the mutator during young gc" phase. That resulted in minor cleanup and regularization of what is done during that phase (wrt to what the corresponding method for full gc does).
> 
> Testing: gha, local perf testing, tier1
> 
> Thanks,
>   Thomas

This pull request has now been integrated.

Changeset: 83e2db6b
Author:    Thomas Schatzl <tschatzl at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/83e2db6ba32e5004d2863e77c9eee91d1b65bd22
Stats:     129 lines in 11 files changed: 94 ins; 20 del; 15 mod

8301116: Parallelize TLAB resizing in G1

Reviewed-by: ayang, iwalulya

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PR: https://git.openjdk.org/jdk/pull/12360