8365199: Use a set instead of a list as the intermediary Klass* storage to reduce typeset processing

[olivergillespie]

Hi all,

Please review this backport of commit 5856dc34.

Mostly clean, just a simple change in the context of jfrSet.hpp because of 8365264: Rename ResourceHashtable to HashTable, but trivial to resolve since this change removes all usage of the hash table in jfrSet anyway.

One of our Corretto 25 users hit significant performance issues (in a use-case that involves massive platform thread churn), which are resolved by this change.

Confirmed that the 'benchmark' in the issue sees the same performance improvement (run-time halved).

// before
java -XX:StartFlightRecording Test  52.40s user 7.03s system 561% cpu 10.592 total
// after
java -XX:StartFlightRecording Test  38.18s user 9.76s system 887% cpu 5.399 total

Thanks!

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Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8365199 needs maintainer approval

Issue

• JDK-8365199: Use a set instead of a list as the intermediary Klass* storage to reduce typeset processing (Enhancement - P3)

Reviewing

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$ git fetch https://git.openjdk.org/jdk25u-dev.git pull/686/head:pull/686
$ git checkout pull/686

Update a local copy of the PR:
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$ git pull https://git.openjdk.org/jdk25u-dev.git pull/686/head

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$ git pr checkout 686

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[bridgekeeper]

👋 Welcome back ogillespie! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

• 00: Full (501d619f)