8294850: Make rs length/pending card predictors dependent on gc phase

[tschatzl]

Hi all,

can I have reviews for this change that separates rs_length and pending_cards predictors by young phase?

Some notes:

• this does not intend to improve the predictors themselves - i.e. the use of xxx_diff and xxx predictors and adding them together is kind of weird, imho trying to add a kind of prediction compensation/improvement to act on differences like a (PID-)controller. I also strongly suspect that the xxx_diff predictors ought to be allowed to report negative values. This is no attempt to fix this
• the parameter for_young_gc in the analytics API is misnamed. It's not about young gcs, but young_only_phase - I will fix this in a follow-up

Depends on PR#10649, please review that one first.

Thanks,
Thomas

Testing: gha, local testing, tier1-5 with other changes in this patch series, perf testing with other changes in this patch series

---

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

Issue

• JDK-8294850: Make rs length/pending card predictors dependent on gc phase

Reviewers

• Kim Barrett (@kimbarrett - Reviewer) ⚠️ Review applies to 35e6be38
• Ivan Walulya (@walulyai - Reviewer) ⚠️ Review applies to 35e6be38
• Albert Mingkun Yang (@albertnetymk - Reviewer) ⚠️ Review applies to 5b6a3f93

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk pull/10650/head:pull/10650
$ git checkout pull/10650

Update a local copy of the PR:
$ git checkout pull/10650
$ git pull https://git.openjdk.org/jdk pull/10650/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 10650

View PR using the GUI difftool:
$ git pr show -t 10650

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/10650.diff

[bridgekeeper]

👋 Welcome back tschatzl! A progress list of the required criteria for merging this PR into pr/10649 will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@tschatzl The following label will be automatically applied to this pull request:

• hotspot-gc

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 02: Full (774edd3d)
• 01: Full - Incremental (5b6a3f93)
• 00: Full (35e6be38)

[kimbarrett]

Looks good.

[albertnetymk]

diff/pending_cards/rs_length are more or less duplicated for young/mixed. I wonder if it's cleaner to encapsulate them in one data structure.

[albertnetymk]

Why _young_pending_cards_seq? I'd expect _mixed_rs_length_seq just to match its neighbor.

[tschatzl]

Typo from breaking up the big patch I had. Good catch! The correct sequence is _mixed_pending_cards_seq though.

[tschatzl]

diff/pending_cards/rs_length are more or less duplicated for young/mixed. I wonder if it's cleaner to encapsulate them in one data structure.

I also considered this, but rs_length_diff will go away completely with other changes after the refinement ones, not sure if pending_cards separation will stay with Kim's changes. Then only rs_length is left.

There are a few others though already. What about doing that separately as cleanup?

[openjdk-notifier]

The parent pull request that this pull request depends on has now been integrated and the target branch of this pull request has been updated. This means that changes from the dependent pull request can start to show up as belonging to this pull request, which may be confusing for reviewers. To remedy this situation, simply merge the latest changes from the new target branch into this pull request by running commands similar to these in the local repository for your personal fork:

git checkout submit/8294850-gc-type-rs-length-predictor
git fetch https://git.openjdk.org/jdk master
git merge FETCH_HEAD
# if there are conflicts, follow the instructions given by git merge
git commit -m "Merge master"
git push

[openjdk]

@tschatzl 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 submit/8294850-gc-type-rs-length-predictor
git fetch https://git.openjdk.org/jdk master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

[openjdk]

@tschatzl 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:

8294850: Make rs length/pending card predictors dependent on gc phase

Reviewed-by: kbarrett, iwalulya, ayang

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 no new commits pushed to the master branch. If another commit should be pushed before you perform the /integrate command, your PR will be automatically rebased. If you prefer to avoid any potential 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.

[tschatzl]

Thanks @albertnetymk @walulyai @kimbarrett for your reviews
/integrate

[openjdk]

Going to push as commit 64813f4.
Since your change was applied there has been 1 commit pushed to the master branch:

• 21e4f06: 8295274: HelidonAppTest.java fails "assert(event->should_commit()) failed: invariant" from compiled frame"

Your commit was automatically rebased without conflicts.

[openjdk]

@tschatzl Pushed as commit 64813f4.

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