8318809: java/util/concurrent/ConcurrentLinkedQueue/WhiteBox.java shows intermittent failures on linux ppc64le and aarch64

[viktorklang-ora]

We've seen some rare failures of the CLQ Whitebox test on "less-strong" architectures, and the only thing which -- given my research -- could be the culprit is spuriously failing weakCAS (which is correct in terms of the implementation of CLQ).

After discussion with @DougLea, it was decided as the CLQ implementation does not guarantee what the failing test tests, and modifying the test would mean that it would generally not be able to enforce anything, the test is invalid and should be removed -- hence this PR.

---

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Issue

• JDK-8318809: java/util/concurrent/ConcurrentLinkedQueue/WhiteBox.java shows intermittent failures on linux ppc64le and aarch64 (Bug - P3)

Reviewers

• Alan Bateman (@AlanBateman - Reviewer)
• Jaikiran Pai (@jaikiran - Reviewer)

Reviewing

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Update a local copy of the PR:
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$ git pull https://git.openjdk.org/jdk.git pull/16786/head

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$ git pr checkout 16786

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[bridgekeeper]

👋 Welcome back vklang! 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]

@viktorklang-ora The following label will be automatically applied to this pull request:

• core-libs

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[viktorklang-ora]

@AlanBateman If you happen to have a couple of seconds to spare, would you mind reviewing this? 🤔

[DougLea]

Looks good to me!

[viktorklang-ora]

/integrate

[openjdk]

@viktorklang-ora This pull request has not yet been marked as ready for integration.

[viktorklang-ora]

/integrate

[openjdk]

@viktorklang-ora This pull request has not yet been marked as ready for integration.

[viktorklang-ora]

/integrate

[openjdk]

@viktorklang-ora 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:

8318809: java/util/concurrent/ConcurrentLinkedQueue/WhiteBox.java shows intermittent failures on linux ppc64le and aarch64

Reviewed-by: alanb, jpai

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 185 new commits pushed to the master branch:

• 81484d8: 8320687: sun.jvmstat.monitor.MonitoredHost.getMonitoredHost() throws unexpected exceptions when invoked concurrently
• 30b5d42: 8321069: JvmtiThreadState::state_for_while_locked() returns nullptr for an attached JNI thread with a java.lang.Thread object after JDK-8319935
• bd04f91: 8321131: Console read line with zero out should zero out underlying buffer in JLine
• 155abc5: 8311906: Improve robustness of String constructors with mutable array inputs
• 316b783: 8321276: runtime/cds/appcds/dynamicArchive/DynamicSharedSymbols.java failed with "'17 2: jdk/test/lib/apps ' missing from stdout/stderr"
• 65be5e0: 8305931: jdk/jfr/jcmd/TestJcmdDumpPathToGCRoots.java failed with "Expected chains but found none"
• f6be922: 8316193: jdk/jfr/event/oldobject/TestListenerLeak.java java.lang.Exception: Could not find leak
• a9de5c7: 8315128: jdk/jfr/event/runtime/TestResidentSetSizeEvent.java fails with "The size should be less than or equal to peak"
• d2c529c: 8319072: JFR: Turn off events for JFR.view
• d5f59cf: 8321220: JFR: RecordedClass reports incorrect modifiers
• ... and 175 more: https://git.openjdk.org/jdk/compare/f69e6653f86a7dd781db6c8523f114c0d3f7ccbc...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.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@AlanBateman, @jaikiran) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[openjdk]

@viktorklang-ora
Your change (at version e7ce355) is now ready to be sponsored by a Committer.

[mlbridge]

Webrevs

• 00: Full (e7ce3557)

[jaikiran]

I see both Doug and Alan have reviewed this.

I'll go ahead and sponsor this now.

[jaikiran]

/sponsor

[openjdk]

Going to push as commit 50d1839.
Since your change was applied there have been 185 commits pushed to the master branch:

• 81484d8: 8320687: sun.jvmstat.monitor.MonitoredHost.getMonitoredHost() throws unexpected exceptions when invoked concurrently
• 30b5d42: 8321069: JvmtiThreadState::state_for_while_locked() returns nullptr for an attached JNI thread with a java.lang.Thread object after JDK-8319935
• bd04f91: 8321131: Console read line with zero out should zero out underlying buffer in JLine
• 155abc5: 8311906: Improve robustness of String constructors with mutable array inputs
• 316b783: 8321276: runtime/cds/appcds/dynamicArchive/DynamicSharedSymbols.java failed with "'17 2: jdk/test/lib/apps ' missing from stdout/stderr"
• 65be5e0: 8305931: jdk/jfr/jcmd/TestJcmdDumpPathToGCRoots.java failed with "Expected chains but found none"
• f6be922: 8316193: jdk/jfr/event/oldobject/TestListenerLeak.java java.lang.Exception: Could not find leak
• a9de5c7: 8315128: jdk/jfr/event/runtime/TestResidentSetSizeEvent.java fails with "The size should be less than or equal to peak"
• d2c529c: 8319072: JFR: Turn off events for JFR.view
• d5f59cf: 8321220: JFR: RecordedClass reports incorrect modifiers
• ... and 175 more: https://git.openjdk.org/jdk/compare/f69e6653f86a7dd781db6c8523f114c0d3f7ccbc...master

Your commit was automatically rebased without conflicts.

[openjdk]

@jaikiran @viktorklang-ora Pushed as commit 50d1839.

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

[theRealAph]

Few AArch64 HotSpot systems implement weak CAS as anything other than plain CAS. In order to get to the root cause of this problem, it would help to know on which AArch64 hardware this test failed.

[viktorklang-ora]

@theRealAph I think the problem in this case was that the whitebox test in this case relied on a presumption that was only true for stronger consistency architectures, and rewriting the test would essentially be asserting that "a lot of permutations are valid, and only internally observable" which is a low-value test.

[theRealAph]

@theRealAph I think the problem in this case was that the whitebox test in this case relied on a presumption that was only true for stronger consistency architectures, and rewriting the test would essentially be asserting that "a lot of permutations are valid, and only internally observable" which is a low-value test.

Oh right, so nothing to do with weak CAS, then. Fair enough.