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8265136: ZGC: Expose GarbageCollectorMXBeans for both pauses and cycles #3483



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@pliden pliden commented Apr 14, 2021

JDK-8240679 introduced a change where the information exposed via the GarbageCollectorMXBean went from being related to the GC pauses to instead be related to the GC cycles. This helped provide more accurate heap usage information. However, some users have noticed that that you no longer get timing information related to the GC pauses, only related to the GC cycle.

Shenandoah has opted for having two distinct memory managers to provide timing information about both pauses and cycles. To align how concurent GCs report this information, ZGC should probably do the same.


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  • Manual testing with relevant jtreg tests


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  • JDK-8265136: ZGC: Expose GarbageCollectorMXBeans for both pauses and cycles



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bridgekeeper bot commented Apr 14, 2021

👋 Welcome back pliden! 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 openjdk bot added the rfr Pull request is ready for review label Apr 14, 2021
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openjdk bot commented Apr 14, 2021

@pliden The following labels will be automatically applied to this pull request:

  • core-libs
  • hotspot-gc
  • serviceability

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

@openjdk openjdk bot added serviceability core-libs hotspot-gc labels Apr 14, 2021
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mlbridge bot commented Apr 14, 2021


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/label remove core-libs

@openjdk openjdk bot removed the core-libs label Apr 14, 2021
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The core-libs label was successfully removed.

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@sspitsyn sspitsyn left a comment

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Hi Per,
It looks good to me.

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openjdk bot commented Apr 15, 2021

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

ℹ️ This project also has non-automated pre-integration requirements. Please see the file for details.

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

8265136: ZGC: Expose GarbageCollectorMXBeans for both pauses and cycles

Reviewed-by: sspitsyn, 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 95 new commits pushed to the master branch:

  • 1ac25b8: 8264372: Threads::destroy_vm only ever returns true
  • 73d5f3b: 8265313: Obsolete the unused AssertOnSuspendWaitFailure and TraceSuspendWaitFailures flags
  • cb8394a: 8265304: Temporarily make Metal the default 2D rendering pipeline for macOS
  • 66f8987: 8265298: Hard VM crash when deadlock between "access" and higher ranked lock is detected
  • 926e3bc: 8264143: Lanai: RenderPerfTest.BgrSwBlitImage has artefacts on apple M1
  • ff49970: 8265375: Bootcycle builds fail with StackOverflowError in cldrconverter
  • c108e7a: 8265154: vinserti128 operand mix up for KNL platforms
  • 2c4075c: 8265381: ProblemList runtime/logging/ on macos-x64 -Xcomp
  • 888d80b: 8265358: ProblemList jdk/jshell/ on macOS-aarch64
  • 0bdc3e7: 8262744: Formatter '%g' conversion uses wrong format for BigDecimal rounding up to limits
  • ... and 85 more:

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.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

@openjdk openjdk bot added the ready Pull request is ready to be integrated label Apr 15, 2021
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pliden commented Apr 20, 2021

Thanks for reviewing @sspitsyn and @albertnetymk!


@openjdk openjdk bot closed this Apr 20, 2021
@openjdk openjdk bot added integrated Pull request has been integrated and removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Apr 20, 2021
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openjdk bot commented Apr 20, 2021

@pliden Since your change was applied there have been 121 commits pushed to the master branch:

  • f1d4ae6: 8263718: unused-result warning happens at os_linux.cpp
  • 787908c: 8264221: Rewrite confusing stream API chain in SnippetMaps
  • 142edd3: 8265152: jpackage cleanup fails on Windows with IOException deleting msi
  • ab22407: 8265486: ProblemList javax/sound/midi/Sequencer/ on macosx-aarch64
  • e0fd5fc: 8265028: JDWP debug agent thread lookup can be made faster
  • 713483c: 8265373: Change to GCC 10.3 for building on Linux at Oracle
  • 3990713: 8265463: ProblemList vmTestbase/vm/mlvm/mixed/stress/regression/b6969574/ on Win-X64 -Xcomp
  • 5b43b39: 8263154: [macos] DMG builds have finder errors
  • 54cb388: 8252600: [JVMCI] remove mx configuration
  • b703e0a: 8264569: Remove obsolete error messages from
  • ... and 111 more:

Your commit was automatically rebased without conflicts.

Pushed as commit 79798c6.

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

@pliden pliden deleted the 8265136_garbagecollectormxbeans branch April 20, 2021 07:54
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