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8279662: serviceability/sa/ClhsdbScanOops.java can fail do to unexpected GC #7295

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@plummercj plummercj commented Feb 1, 2022

The test is failing to find certain types in the scanoops output when run with -Xcomp. This is happening in the loom repo. The reason it is happening there is because loom introduced a full GC during codecache sweeping. The test only runs scanoops on the eden gen, and the full GC is causing objects of certain expected types to no longer be present in the eden gen. The fix is to also check the old gen.

The logic of the test had to be reworked a bit to accomplish checking the output of two scanoops commands together. It was relying on the ClhsdbLauncher class to check the output for expected strings, but in this case we need to accumulate the output of the two scanoops commands and check the combined output for the expected strings, so now the checking is done directly by the test and not by ClhsdbLauncher.

I'm choosing to fix this in the jdk repo rather than the loom repo since it is a latent bug that theoretically could occur even without the loom changes, and also to help reduce the amount of changes to be reviewed when loom is integrated into jdk.


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  • JDK-8279662: serviceability/sa/ClhsdbScanOops.java can fail do to unexpected GC

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bridgekeeper bot commented Feb 1, 2022

👋 Welcome back cjplummer! 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.

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openjdk bot commented Feb 1, 2022

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

  • serviceability

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

@openjdk openjdk bot added the serviceability label Feb 1, 2022
@plummercj plummercj marked this pull request as ready for review Feb 1, 2022
@openjdk openjdk bot added the rfr label Feb 1, 2022
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mlbridge bot commented Feb 1, 2022

Webrevs

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@sspitsyn sspitsyn left a comment

Looks reasonable to me.
There is minor duplication but it is okay as there is no good way to get rid of it.
Thanks,
Serguei

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openjdk bot commented Feb 2, 2022

@plummercj 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:

8279662: serviceability/sa/ClhsdbScanOops.java can fail do to unexpected GC

Reviewed-by: sspitsyn, kevinw

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 221 new commits pushed to the master branch:

  • de826ba: 8280600: C2: assert(!had_error) failed: bad dominance
  • 4304a77: 8279535: C2: Dead code in PhaseIdealLoop::create_loop_nest after JDK-8276116
  • ab63834: 8280885: Shenandoah: Some tests failed with "EA: missing allocation reference path"
  • 48a32b5: 8280976: Incorrect encoding of avx512 vpsraq instruction with mask and constant shift.
  • 97af323: 8280842: Access violation in ciTypeFlow::profiled_count
  • d32f99e: 8279219: [REDO] C2 crash when allocating array of size too large
  • 85d839f: 8280601: ClhsdbThreadContext.java test is triggering codecache related asserts
  • 9ca7ff3: 8281082: Improve javadoc references to JOSS
  • c74b8f4: 8275914: SHA3: changing java implementation to help C2 create high-performance code
  • a18beb4: 8280867: Cpuid1Ecx feature parsing is incorrect for AMD CPUs
  • ... and 211 more: https://git.openjdk.java.net/jdk/compare/46fd683820bb7149c0605a0ba03f59e76de69c16...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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plummercj commented Feb 2, 2022

There is minor duplication but it is okay as there is no good way to get rid of it.

I considered a loop or common method, but it seemed not to be worth it and likely less readable.

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sspitsyn commented Feb 2, 2022

Agreed.

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@kevinjwalls kevinjwalls left a comment

Looks good.
For the scanoops for a type, it seems like a reasonable assumption that there will be a String in the old gen!

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plummercj commented Feb 2, 2022

For the scanoops for a type, it seems like a reasonable assumption that there will be a String in the old gen!

Actually it's not, and that's why I check the Eden gen. If a GC is not triggered, the old gen will be empty. It not actually guaranteed that a String will be in the Eden gen either, but at least at the moment that appears to be the case whether or not a GC is triggered.

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kevinjwalls commented Feb 2, 2022

Actually it's not, and that's why I check the Eden gen.

Yes sorry, should have said it's a good bet to find a String when only checking one generation. Carry on...

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plummercj commented Feb 2, 2022

/integrate

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openjdk bot commented Feb 2, 2022

Going to push as commit fe0118f.
Since your change was applied there have been 228 commits pushed to the master branch:

  • e3d5c9e: 8266974: duplicate property key in java.sql.rowset resource bundle
  • 47800bf: 8280868: LineBodyHandlerTest.java creates and discards too many clients
  • 9d57853: 8281042: G1: Remove unused init_threshold in G1FullGCCompactionPoint
  • 87ab099: 8280944: Enable Unix domain sockets in Windows Selector notification mechanism
  • ce71e8b: 8279917: Refactor subclassAudits in Thread to use ClassValue
  • 4ea6037: 8281035: Serial: Move RemoveForwardedPointerClosure to local scope
  • ae2504b: 8278254: Cleanup doclint warnings in java.desktop module
  • de826ba: 8280600: C2: assert(!had_error) failed: bad dominance
  • 4304a77: 8279535: C2: Dead code in PhaseIdealLoop::create_loop_nest after JDK-8276116
  • ab63834: 8280885: Shenandoah: Some tests failed with "EA: missing allocation reference path"
  • ... and 218 more: https://git.openjdk.java.net/jdk/compare/46fd683820bb7149c0605a0ba03f59e76de69c16...master

Your commit was automatically rebased without conflicts.

@openjdk openjdk bot added the integrated label Feb 2, 2022
@openjdk openjdk bot closed this Feb 2, 2022
@openjdk openjdk bot removed ready rfr labels Feb 2, 2022
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openjdk bot commented Feb 2, 2022

@plummercj Pushed as commit fe0118f.

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

@plummercj plummercj deleted the 8279662-scanoops branch Feb 2, 2022
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