8348829: Remove ObjectMonitor perf counters

[shipilev]

See bug for more discussion. I believe these counters are useless and come with more trouble than their worth.

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Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Change requires CSR request JDK-8348833 to be approved
• Commit message must refer to an issue

Issues

• JDK-8348829: Remove ObjectMonitor perf counters (Enhancement - P4)
• JDK-8348833: Remove ObjectMonitor perf counters (CSR)

Reviewers

• David Holmes (@dholmes-ora - Reviewer) Review applies to 79316c15
• Coleen Phillimore (@coleenp - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/23326/head:pull/23326
$ git checkout pull/23326

Update a local copy of the PR:
$ git checkout pull/23326
$ git pull https://git.openjdk.org/jdk.git pull/23326/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 23326

View PR using the GUI difftool:
$ git pr show -t 23326

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/23326.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back shade! 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]

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• hotspot-runtime

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[shipilev]

/csr needed

[openjdk]

@shipilev an approved CSR request is already required for this pull request.

[mlbridge]

Webrevs

• 01: Full (4a0e1d33)
• 00: Full (79316c15)

[dholmes-ora]

Assuming CSR request confirms desirability of deleting these perf counters, the actual deletion seems good. Thanks

[openjdk]

@shipilev this pull request can not be integrated into master due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

git checkout JDK-8348829-remove-om-counters
git fetch https://git.openjdk.org/jdk.git master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

[bridgekeeper]

@shipilev This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply add a new comment to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

[coleenp]

Looks good. You might need a remerge after PR #23421 once the CSR is approved.

[shipilev]

Thanks! I looked deeper what JFR events are available to capture what where these counters help, and I think we want a few new ones (see linked issues). Adding these new JFR events would require code changes in the vicinity of this PR, so I would have to re-merge anyway. Until those events land, this PR is on hold.