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

[mrserb]

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

---

Progress

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Issue

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

Reviewers

• Phil Race (@prrace - Reviewer)

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[mrserb]

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.

[mlbridge]

Webrevs

• 00: Full (fa02c3c1)

[prrace]

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

[prrace]

Testing was OK

[openjdk]

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

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

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

Reviewed-by: prr

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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.

[mrserb]

/integrate

[openjdk]

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]

@mrserb Pushed as commit e49e5b5.

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