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8273972: Multi-core choke point in CMM engine (LCMSTransform.doTransform) #5671

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@mrserb mrserb commented Sep 24, 2021

Initially, the bug was discussed here:
https://stackoverflow.com/questions/35264582/why-is-multithreading-slowing-down/35264813

The root cause is that if for some reason directly or indirectly the color transform object is shared across the threads it cannot be used for parallel color transformation because the method LCMSTransform.doTransform() is synchronized.

This code seems to be created when the littlecms 1.x was used which was not thread-safe, but the latest version is thread safe (subject to bugs). I can check that by compiling lcms with #define CMS_NO_PTHREADS which will cause some of our tests fail here and there.

To check that transform can be used across the threads I created two quite heavyweight tests which tests different color transformations using different threads.

The fix moves the data for the native transform from the LCMSTransform object to the NativeTransform class just to simplify synchronization steps, so only one volatile read of "transform" is executed in the common path.

Result for the testcase attached to SO: https://stackoverflow.com/a/35264713

№ threads Before the fix After the fix
1 693 ms 699 ms
8 6641 ms 873 ms
30 34069 ms 1034 ms

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  • JDK-8273972: Multi-core choke point in CMM engine (LCMSTransform.doTransform)

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@bridgekeeper bridgekeeper bot commented Sep 24, 2021

👋 Welcome back serb! 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 openjdk bot commented Sep 24, 2021

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

  • client

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 client label Sep 24, 2021
* @test
* @bug 8273972
* @summary Verifies that ColorConvertOp works fine if shared between threads
* @run main/othervm/timeout=600 MTTransformValidation
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@mrserb mrserb Sep 24, 2021

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600 is quite pessimistic, on my system both tests are executed around 1 minute, but I am not sure how it will execute on the slow mac mini, so increased the timeout.

@mrserb mrserb marked this pull request as ready for review Sep 24, 2021
@openjdk openjdk bot added the rfr label Sep 24, 2021
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@mlbridge mlbridge bot commented Sep 24, 2021

Webrevs

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@prrace prrace commented Sep 25, 2021

This looks OK but I want to submit a test job to make sure no nasty surprises

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prrace approved these changes Sep 26, 2021
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@prrace prrace left a comment

Testing was OK

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@openjdk openjdk bot commented Sep 27, 2021

@mrserb 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:

8273972: Multi-core choke point in CMM engine (LCMSTransform.doTransform)

Reviewed-by: prr

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 25 new commits pushed to the master branch:

  • 252aaa9: 8274293: Build failure on macOS with Xcode 13.0 as vfork is deprecated
  • 7700b25: 8273401: Disable JarIndex support in URLClassPath
  • 5ec1cdc: 8274321: Standardize values of @SInCE tags in javax.lang.model
  • 4838a2c: 8274143: Disable "invalid entry for security.provider.X" error message in log file when security.provider.X is empty
  • ab28db1: 8274312: ProblemList 2 serviceability/dcmd/gc tests with ZGC on macos-all
  • 8c122af: 8274314: Typo in WatchService#poll(long timeout, TimeUnit unit) javadoc
  • 9bc865d: 8273960: Redundant condition in Metadata.TypeComparator.compare
  • 5756385: 8274273: Update testing docs for MacOS with Non-US locale
  • 61ac53f: 8210927: JDB tests do not update source path after doing a redefine class
  • 341de49: 8273492: Move evacuation failure handling into G1YoungCollector
  • ... and 15 more: https://git.openjdk.java.net/jdk/compare/56b8b35286634f2d2224ca445bc9f32ff284ae74...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.

➡️ 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 label Sep 27, 2021
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@mrserb mrserb commented Sep 28, 2021

/integrate

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@openjdk openjdk bot commented Sep 28, 2021

Going to push as commit e49e5b5.
Since your change was applied there have been 55 commits pushed to the master branch:

  • 2072bc7: 8274391: Suppress more warnings on non-serializable non-transient instance fields in java.util.concurrent
  • 6a477bd: 8274415: Suppress warnings on non-serializable non-transient instance fields in java.xml
  • 67e52a3: 8273634: [TEST_BUG] Improve javax/swing/text/ParagraphView/6364882/bug6364882.java
  • b7425b6: 8239502: [TEST_BUG] Test javax/swing/text/FlowView/6318524/bug6318524.java never fails
  • c57a6c6: 8274265: Suspicious string concatenation in logTestUtils.inline.hpp
  • 6f4cefb: 8274394: Use Optional.isEmpty instead of !Optional.isPresent in jdk.jlink
  • 94f5e80: 8274276: Cache normalizedBase URL in URLClassPath.FileLoader
  • b36881f: 8274383: JNI call of getAccessibleSelection on a wrong thread
  • be40373: 8274381: missing CAccessibility definitions in JNI code
  • 79865cd: 8274259: G1: assert(check_alignment(result)) failed: address not aligned: 0x00000008baadbabe after JDK-8270009
  • ... and 45 more: https://git.openjdk.java.net/jdk/compare/56b8b35286634f2d2224ca445bc9f32ff284ae74...master

Your commit was automatically rebased without conflicts.

@openjdk openjdk bot closed this Sep 28, 2021
@openjdk openjdk bot added integrated and removed ready rfr labels Sep 28, 2021
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@openjdk openjdk bot commented Sep 28, 2021

@mrserb Pushed as commit e49e5b5.

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

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