RFR: 8345732: Provide helpers for using PartialArrayState [v4]
Zhengyu Gu
zgu at openjdk.org
Wed Dec 18 01:09:37 UTC 2024
On Tue, 17 Dec 2024 18:08:23 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:
>> Please review this change that introduces two new helper classes to simplify
>> the usage of PartialArrayStates to manage splitting the processing of large
>> object arrays into parallelizable chunks. G1 and Parallel young GCs are
>> changed to use this new mechanism.
>>
>> PartialArrayTaskStats is used to collect and report statistics related to
>> array splitting. It replaces the direct implementation in PSPromotionManager,
>> and is now also used by G1 young GCs.
>>
>> PartialArraySplitter packages up most of the work involved in splitting and
>> processing tasks. It provides task allocation and release, enqueuing, chunk
>> claiming, and statistics tracking. It does this by encapsulating existing
>> objects and functionality. Using array splitting is mostly reduced to calling
>> the splitter's start function and then calling it's step function to process
>> partial states. This substantially reduces the amount of code for each client
>> to perform this work.
>>
>> Testing: mach5 tier1-5
>>
>> Manually ran some test programs with each of G1 and Parallel, with taskqueue
>> stats logging enabled, and checked that the logged statistics looked okay.
>
> Kim Barrett has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 14 additional commits since the last revision:
>
> - Merge branch 'master' into pa-splitter
> - merge log_set decl/defn
> - remove default counts for stats incrementers
> - remove uneeded 'explicit'
> - cleanup unneeded includes
> - remove moved-from macro defines
> - Merge branch 'master' into pa-splitter
> - rename splitter.step() => claim()
> - simplify comments
> - Merge branch 'master' into pa-splitter
> - ... and 4 more: https://git.openjdk.org/jdk/compare/9fad115b...54c37988
LGTM
-------------
Marked as reviewed by zgu (Reviewer).
PR Review: https://git.openjdk.org/jdk/pull/22622#pullrequestreview-2510521893
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