8315702: jcmd Thread.dump_to_file slow with millions of virtual threads

[robm-openjdk]

backport 8315702

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8315702 needs maintainer approval

Issue

• JDK-8315702: jcmd Thread.dump_to_file slow with millions of virtual threads (Bug - P4 - Approved)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk21u.git pull/170/head:pull/170
$ git checkout pull/170

Update a local copy of the PR:
$ git checkout pull/170
$ git pull https://git.openjdk.org/jdk21u.git pull/170/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 170

View PR using the GUI difftool:
$ git pr show -t 170

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk21u/pull/170.diff

[bridgekeeper]

👋 Welcome back robm! 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 backport pull request has now been updated with issue from the original commit.

[openjdk]

⚠️ @robm-openjdk This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[openjdk]

@robm-openjdk This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8315702: jcmd Thread.dump_to_file slow with millions of virtual threads

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 1 new commit pushed to the master branch:

• 84cde0f: 8314759: VirtualThread.parkNanos timeout adjustment when pinned should be replaced

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[robm-openjdk]

/integrate

[openjdk]

Going to push as commit b8f0f91.
Since your change was applied there has been 1 commit pushed to the master branch:

• 84cde0f: 8314759: VirtualThread.parkNanos timeout adjustment when pinned should be replaced

Your commit was automatically rebased without conflicts.

[openjdk]

@robm-openjdk Pushed as commit b8f0f91.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

[mlbridge]

Webrevs

• 00: Full (112a8533)