8269304: Regression ~5% in 2005 in b27

[vnkozlov]

JDK-8268347 changes missed check for valid case when all locks/unlocks in coarsened group were eliminated.
As result methods were recompiled without locks coarsening optimization leaving locks in code.

Tested tier1-3, xcomp, performance.

---

Progress

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Issue

• JDK-8269304: Regression ~5% in 2005 in b27

Reviewers

• Dean Long (@dean-long - Reviewer)
• Roland Westrelin (@rwestrel - Reviewer)

Reviewing

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[bridgekeeper]

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[openjdk]

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

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[mlbridge]

Webrevs

• 00: Full (cc95e428)

[dean-long]

The size == 0 case makes sense. Is there a possible situation where some locks were removed, but the remaining are still balanced?

[vnkozlov]

Yes. For example, if one of branches in case 1 is eliminated after locks/unlocks marked as coarsened:
https://github.com/openjdk/jdk/blob/master/src/hotspot/share/opto/callnode.cpp#L1779

jbb2005 does not have such cases. And It would be really hard to separate such case from failing case in current implementation.

I have RFE 8268571 it improve locks elimination I hope I can work on in JDK 18.

[openjdk]

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

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

8269304: Regression ~5% in 2005 in b27

Reviewed-by: dlong, roland

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At the time when this comment was updated there had been 3 new commits pushed to the master branch:

• d9cb068: 8258746: illegal access to global field _jvmci_old_thread_counters by terminated thread causes crash
• 6eb734a: 8266269: Lookup::accessClass fails with IAE when accessing an arrayClass with a protected inner class as component class
• 3d0d27c: 8269351: Proxy::newProxyInstance and MethodHandleProxies::asInterfaceInstance should reject sealed interfaces

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
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[rwestrel]

Looks good to me.

[vnkozlov]

Thank you, Dean and Roland.

[vnkozlov]

/integrate

[openjdk]

Going to push as commit 8d09596.
Since your change was applied there have been 4 commits pushed to the master branch:

• e4c5446: 8268236: The documentation of the String.regionMatches method contains error
• d9cb068: 8258746: illegal access to global field _jvmci_old_thread_counters by terminated thread causes crash
• 6eb734a: 8266269: Lookup::accessClass fails with IAE when accessing an arrayClass with a protected inner class as component class
• 3d0d27c: 8269351: Proxy::newProxyInstance and MethodHandleProxies::asInterfaceInstance should reject sealed interfaces

Your commit was automatically rebased without conflicts.

[openjdk]

@vnkozlov Pushed as commit 8d09596.

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