8390907: Genshen: Improve mark loop performance

[earthling-amzn]

There are several small changes here that add up to a 10% to 12% reduction in mark times on specjbb2015.

• Gate the re-remembering work on a template parameter so that only the remembered set scan closure needs to do it
• Bias the affiliation byte array to eliminate a subtraction for every oop
• Loosen the check on heap inclusion for decoded oops
• Inline the card marking function
• Inline age census add function
• Test for two pointers being in the same region before testing if old points to young

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Issue

• JDK-8390907: Genshen: Improve mark loop performance (Enhancement - P4)

Reviewers

• Kelvin Nilsen (@kdnilsen - Reviewer)
• Aleksey Shipilev (@shipilev - Reviewer)

Reviewing

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[bridgekeeper]

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[openjdk]

@earthling-amzn This change now passes all automated pre-integration checks.

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

8390907: Genshen: Improve mark loop performance

Reviewed-by: kdnilsen, shade

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At the time when this comment was updated there had been 20 new commits pushed to the master branch:

• edb2326: 8383246: Add relaxed implementations of atomics for Windows/AArch64
• 30df8a5: 8383460: Replace "sharing" in VM version string with "aot" information
• 5b96789: 8390906: Allow to collect per-test code coverage information
• ... and 17 more: https://git.openjdk.org/jdk/compare/f40a2c3625484087cfdb41d34b360414ccf0ebd0...master

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.

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[openjdk]

@earthling-amzn The following labels will be automatically applied to this pull request:

• hotspot-gc
• shenandoah

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[shipilev]

Functions like these really belong in .inline.hpp. Putting anything non-trivial in the .hpp risks circular dependencies that are hard to untangle.

[openjdk]

@earthling-amzn 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 simplify-reremember-during-mark
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

[shipilev]

In my runs, I also see ShenandoahAgeCensus::add not inlined. Have you seen it in yours?

[mlbridge]

Webrevs

• 01: Full - Incremental (0cf23194)
• 00: Full (38039654)

[kdnilsen]

Thanks. Nice performance improvements.

[shipilev]

Looks all right with a few nits.

[shipilev]

This moves dates backwards, so it does not look right.

[earthling-amzn]

Sorry, bad merge.

[shipilev]

Just for my understanding. This is a narrower check than we can do? I would have tried to check that region affiliations are different. But that performs access to affiliation bitmap, so that's why we do this address-only check, right?

[earthling-amzn]

Right, it's meant to be a cheap test that the pointers are in different regions to avoid looking up their respective affiliations.

[earthling-amzn]

Failures look like network timeouts or other infrastructure issues.

/integrate

[openjdk]

Going to push as commit c86277f.
Since your change was applied there have been 22 commits pushed to the master branch:

• 4254168: 8390874: MethodData::extra_data_lock memory leak
• ab00564: 8388833: Fix JDWP spec w.r.t. setting static final fields and provide warnings about setting final fields
• edb2326: 8383246: Add relaxed implementations of atomics for Windows/AArch64
• ... and 19 more: https://git.openjdk.org/jdk/compare/f40a2c3625484087cfdb41d34b360414ccf0ebd0...master

Your commit was automatically rebased without conflicts.

[openjdk]

@earthling-amzn Pushed as commit c86277f.

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