8263579: ZGC: Concurrent mark hangs with debug loglevel

[casparcwang]

Do not leave terminate stage 1 when there is nothing to do. This helps eliminate the concurrent mark hang with debug log level, and reduce total mark time without impact the performance.

The following is the performance data of specjbb2015 with stressed zgc:
Current patch:
RUN RESULT: hbIR (max attempted) = 122581, hbIR (settled) = 102168, max-jOPS = 104194, critical-jOPS = 90630
[2021-03-12T17:20:37.072+0800][info ][gc,stats ] Phase: Concurrent Mark 383.026 / 383.026 1222.317 / 1811.813 766.530 / 1811.813 766.530 / 1811.813 ms

RUN RESULT: hbIR (max attempted) = 118234, hbIR (settled) = 108389, max-jOPS = 102864, critical-jOPS = 93572
[2021-03-12T19:28:01.032+0800][info ][gc,stats ] Phase: Concurrent Mark 407.483 / 407.483 1243.775 / 1773.463 756.956 / 1773.463 756.956 / 1773.463 ms

RUN RESULT: hbIR (max attempted) = 111999, hbIR (settled) = 110683, max-jOPS = 104159, critical-jOPS = 92600
[2021-03-12T21:48:09.729+0800][info ][gc,stats ] Phase: Concurrent Mark 412.954 / 412.954 1216.900 / 1927.552 762.315 / 1927.552 762.315 / 1927.552 ms

Original:
RUN RESULT: hbIR (max attempted) = 122581, hbIR (settled) = 109863, max-jOPS = 102968, critical-jOPS = 90836
[2021-03-13T01:59:35.160+0800][info ][gc,stats ] Phase: Concurrent Mark 414.845 / 414.845 1168.357 / 1817.015 795.806 / 1837.452 795.806 / 1837.452 ms

RUN RESULT: hbIR (max attempted) = 122581, hbIR (settled) = 102168, max-jOPS = 102968, critical-jOPS = 89227
[2021-03-12T23:49:17.322+0800][info ][gc,stats ] Phase: Concurrent Mark 405.709 / 405.709 1250.672 / 1724.725 783.993 / 1739.099 783.993 / 1739.099 ms

RUN RESULT: hbIR (max attempted) = 102168, hbIR (settled) = 85156, max-jOPS = 104211, critical-jOPS = 91693
[2021-03-13T04:22:14.338+0800][info ][gc,stats ] Phase: Concurrent Mark 415.444 / 415.444 1254.256 / 1896.037 768.536 / 1896.037 768.536 / 1896.037 ms

---

Progress

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Issue

• JDK-8263579: ZGC: Concurrent mark hangs with debug loglevel

Reviewers

• Per Liden (@pliden - Reviewer)
• Albert Mingkun Yang (@albertnetymk - Committer)
• Erik Österlund (@fisk - Reviewer)

Download

To checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/3011/head:pull/3011
$ git checkout pull/3011

To update a local copy of the PR:
$ git checkout pull/3011
$ git pull https://git.openjdk.java.net/jdk pull/3011/head

[bridgekeeper]

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[openjdk]

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[mlbridge]

Webrevs

• 01: Full - Incremental (e2280fd)
• 00: Full (56f74da01c8e2f81dd026ebe8d4ff216fc30322e)

[pliden]

Thanks for reporting and proposing a fix. I would suggest that we simply remove the ZSubPhaseConcurrentMarkIdle stat timer completely, since that timer isn't that useful anyway.

[casparcwang]

Thanks for reporting and proposing a fix. I would suggest that we simply remove the ZSubPhaseConcurrentMarkIdle stat timer completely, since that timer isn't that useful anyway.

Thanks for your review @pliden . The patch is changed according to your suggestion, and removing ZSubPhaseConcurrentMarkIdle solves the problem in the test environment.

The destruction of ZSubPhaseConcurrentMarkIdle and ZSubPhaseConcurrentMarkTryTerminate produce lots of lock contention, which result in the hang. Only removing ZSubPhaseConcurrentMarkIdle can reduce the contention of gc log lock, but there still exists contention of gc log lock of ZSubPhaseConcurrentMarkTryTerminate after _terminate.try_exit_stage0(), which may result in jvm hang or long concurrent mark time in some un-explored scenario.

[pliden]

Looks good!

[fisk]

Looks good.

[casparcwang]

/integrate

[openjdk]

@casparcwang This PR has not yet been marked as ready for integration.

[casparcwang]

/issue add JDK-8263579

[openjdk]

@casparcwang The primary solved issue for a PR is set through the PR title. Since the current title does not contain an issue reference, it will now be updated.

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[openjdk]

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

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

8263579: ZGC: Concurrent mark hangs with debug loglevel

Reviewed-by: pliden, ayang, eosterlund

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At the time when this comment was updated there had been 350 new commits pushed to the master branch:

• 35cd945: 8263908: Build fails due to initialize_static_field_for_dump defined but not used after JDK-8263771
• cd45538: 8263771: Refactor javaClasses initialization code to isolate dumping code
• 118a49f: 8263846: Bad JNI lookup getFocusOwner in accessibility code on Mac OS X
• cb742f9: 8255255: Update Apache Santuario (XML Signature) to version 2.2.1
• d2c137d: 8263558: Possible NULL dereference in fast path arena free if ZapResourceArea is true
• ab66d69: 8263138: Initialization of sun.font.SunFontManager.platformFontMap is not thread safe
• 5b8233b: 8263871: On sem_destroy() failing we should assert
• 96e5c3f: 8263890: Broken links to Unicode.org
• 4d9517d: 8263834: Work around gdb for HashtableEntry
• 6fa6557: 8263825: Remove unused and commented out member from NTLMException
• ... and 340 more: https://git.openjdk.java.net/jdk/compare/3e13b66e3fd878889cb22e9bf4c79b41a11e36a5...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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➡️ 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).

[casparcwang]

/integrate

[openjdk]

@casparcwang
Your change (at version e2280fd) is now ready to be sponsored by a Committer.

[DamonFool]

/sponsor

[openjdk]

@DamonFool @casparcwang Since your change was applied there have been 350 commits pushed to the master branch:

• 35cd945: 8263908: Build fails due to initialize_static_field_for_dump defined but not used after JDK-8263771
• cd45538: 8263771: Refactor javaClasses initialization code to isolate dumping code
• 118a49f: 8263846: Bad JNI lookup getFocusOwner in accessibility code on Mac OS X
• cb742f9: 8255255: Update Apache Santuario (XML Signature) to version 2.2.1
• d2c137d: 8263558: Possible NULL dereference in fast path arena free if ZapResourceArea is true
• ab66d69: 8263138: Initialization of sun.font.SunFontManager.platformFontMap is not thread safe
• 5b8233b: 8263871: On sem_destroy() failing we should assert
• 96e5c3f: 8263890: Broken links to Unicode.org
• 4d9517d: 8263834: Work around gdb for HashtableEntry
• 6fa6557: 8263825: Remove unused and commented out member from NTLMException
• ... and 340 more: https://git.openjdk.java.net/jdk/compare/3e13b66e3fd878889cb22e9bf4c79b41a11e36a5...master

Your commit was automatically rebased without conflicts.

Pushed as commit 5a7f22a.

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