Add PollsetSelector implementation to resolve the performance degradation #1000

shruacha1234 · 2025-12-02T12:41:12Z

This PR integrates a more efficient selector path in AIX using PollsetSelector to improve overall system responsiveness. It addresses the reported performance issues and ensures stable operation under high load scenarios.

pshipton · 2025-12-05T12:39:33Z

Pls fix the line endings check failures.
https://openj9-jenkins.osuosl.org/job/PullRequest-LineEndingsCheck-OpenJDK11/1359/console

pshipton · 2025-12-05T12:40:09Z

jenkins test sanity,sanity.system aix jdk11

pshipton · 2025-12-05T13:15:35Z

jenkins compile xlinux,xmac,amac jdk11

pshipton · 2025-12-05T13:41:37Z

See the xlinux compile failure
https://openj9-jenkins.osuosl.org/job/Build_JDK11_x86-64_linux_Personal/1114/

pshipton · 2025-12-05T21:22:15Z

Further testing in https://trssrtp1.fyre.ibm.com/resultSummary?parentId=69332b893f6dc49d2fb8e4b9

It's still running, but there is a stack overflow failure running renaissance-movie-lens_0, which I repeated in a grinder.
https://hyc-runtimes-jenkins.swg-devops.com/job/Test_openjdk11_j9_extended.perf_ppc64_aix/295/
https://hyc-runtimes-jenkins.swg-devops.com/job/Grinder/56743

The same test is passing with the previous nightly build.
https://hyc-runtimes-jenkins.swg-devops.com/job/Grinder/56744
also with the next nightly build, so it's not caused by some other change.
https://hyc-runtimes-jenkins.swg-devops.com/job/Grinder/56748

shruacha1234 · 2025-12-08T05:52:45Z

jenkins compile xlinux jdk11

Ravi-Patel8 · 2025-12-08T11:15:48Z

jenkins compile xlinux jdk11

Ravi-Patel8 · 2025-12-08T12:34:19Z

jenkins compile xlinux,xmac,amac jdk11

Ravi-Patel8 · 2025-12-08T12:40:16Z

Further testing in https://trssrtp1.fyre.ibm.com/resultSummary?parentId=69332b893f6dc49d2fb8e4b9

It's still running, but there is a stack overflow failure running renaissance-movie-lens_0, which I repeated in a grinder. https://hyc-runtimes-jenkins.swg-devops.com/job/Test_openjdk11_j9_extended.perf_ppc64_aix/295/ https://hyc-runtimes-jenkins.swg-devops.com/job/Grinder/56743

The same test is passing with the previous nightly build. https://hyc-runtimes-jenkins.swg-devops.com/job/Grinder/56744 also with the next nightly build, so it's not caused by some other change. https://hyc-runtimes-jenkins.swg-devops.com/job/Grinder/56748

@pshipton , the stack overflow failure appears to be a machine-specific issue. We’ve triggered the run on another machine and all tests are passing:
https://hyc-runtimes-jenkins.swg-devops.com/job/Grinder/56756/

Ravi-Patel8 · 2025-12-08T12:42:41Z

@pshipton ,
I commented jenkins compile xlinux,xmac,amac jdk11 to validate if the xlinux failure. But seems the tests are not being run. Could you please check once?

shruacha1234 · 2025-12-09T10:47:00Z

@pshipton
I triggered the xlinux personal build with this patch, and it passed.
https://hyc-runtimes-jenkins.swg-devops.com/job/Build_JDK11_x86-64_linux_Personal/8088/

pshipton · 2025-12-09T13:52:35Z

jenkins test sanity,sanity.system xlinux jdk11

pshipton · 2025-12-09T16:54:18Z

Pls see the failures in https://trssrtp1.fyre.ibm.com/output/test?id=693375823f6dc49d2fbe7452

java/nio/channels/AsynchronousServerSocketChannel/WithSecurityManager.java
java/nio/channels/SocketChannel/OpenLeak.java

[2025-12-05T20:38:33.500Z] Caused by: java.security.AccessControlException: Access denied ("java.util.PropertyPermission" "java.nio.channels.spi.SelectorProvider" "read")
[2025-12-05T20:38:33.500Z] 	at java.base/java.security.AccessController.throwACE(AccessController.java:180)
[2025-12-05T20:38:33.500Z] 	at java.base/java.security.AccessController.checkPermissionHelper(AccessController.java:244)
[2025-12-05T20:38:33.500Z] 	at java.base/java.security.AccessController.checkPermission(AccessController.java:391)
[2025-12-05T20:38:33.500Z] 	at java.base/java.lang.SecurityManager.checkPermission(SecurityManager.java:322)
[2025-12-05T20:38:33.500Z] 	at java.base/java.lang.SecurityManager.checkPropertyAccess(SecurityManager.java:1066)
[2025-12-05T20:38:33.500Z] 	at java.base/java.lang.System.getProperty(System.java:597)
[2025-12-05T20:38:33.500Z] 	at java.base/java.lang.System.getProperty(System.java:580)
[2025-12-05T20:38:33.500Z] 	at java.base/sun.nio.ch.PollsetSelectorFeature.pollsetEnabled(PollsetSelectorFeature.java:44)

java/nio/channels/SocketChannel/CloseDuringConnect.java failed with a timeout.

[2025-12-05T21:03:40.249Z] "InnocuousThread-3" prio=5 Id=30 RUNNABLE
[2025-12-05T21:03:40.249Z] 	at [email protected]/sun.nio.ch.AixPollPort.pollsetPoll(Native Method)
[2025-12-05T21:03:40.249Z] 	at [email protected]/sun.nio.ch.AixPollPort$EventHandlerTask.poll(AixPollPort.java:328)
[2025-12-05T21:03:40.249Z] 	at [email protected]/sun.nio.ch.AixPollPort$EventHandlerTask.run(AixPollPort.java:425)
[2025-12-05T21:03:40.249Z] 	at [email protected]/sun.nio.ch.AsynchronousChannelGroupImpl$1.run(AsynchronousChannelGroupImpl.java:112)

src/jdk.net/share/classes/jdk/nio/Channels.java

pshipton · 2025-12-09T18:51:32Z

Further xlinux testing in https://trssrtp1.fyre.ibm.com/resultSummary?parentId=6938542a3e3bd23d4c2afa4b

The same failures as #1000 (comment) plus others in the next comment.

pshipton · 2025-12-10T16:31:20Z

There are some additional failures on xlinux.

java/nio/channels/spi/SelectorProvider/inheritedChannel/InheritedChannelTest.java - timeout
java/nio/channels/AsyncCloseAndInterrupt.java - timeout/hang

…tion This change brings the PollsetSelector implementation to address the performance degradation reported by a customer. The new implementation reduces thread stalls and CPU spikes by improving event handling. Validated with customer workloads showing full performance recovery. Signed-off-by: Shruthi <[email protected]>

shruacha1234 · 2025-12-11T15:35:27Z

@pshipton
I have addressed the failures you mentioned and rerun the jdk_net, java_io, and java_nio tests for AIX. All of them are passing now.
https://hyc-runtimes-jenkins.swg-devops.com/job/Grinder_CR/49937/

17:11:31  TEST TARGETS SUMMARY
17:11:31  ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
17:11:31  PASSED test targets:
17:11:31  	jdk_io_0 - Test results: passed: 362 
17:11:31  	jdk_io_1 - Test results: passed: 362 
17:11:31  	jdk_net_0 - Test results: passed: 723 
17:11:31  	jdk_net_1 - Test results: passed: 723 
17:11:31  	jdk_nio_0 - Test results: passed: 383 
17:11:31  	jdk_nio_1 - Test results: passed: 383 
17:11:31  
17:11:31  TOTAL: 9   EXECUTED: 6   PASSED: 6   FAILED: 0   SKIPPED: 3
17:11:31  ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
17:11:31  
17:11:31  TESTCASES RESULTS SUMMARY: passed: 2,936; failed: 0; error: 0; skipped: 0
17:11:31  ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
17:11:31  ALL TESTS PASSED

pshipton · 2025-12-12T03:42:00Z

src/java.base/share/classes/sun/nio/ch/SelectionKeyImpl.java

-    private final SelChImpl channel;
-    private final SelectorImpl selector;
+    protected final SelChImpl channel;
+    public final SelectorImpl selector;


Pls add a public access for this rather than making the variable public.

pshipton · 2025-12-12T03:47:15Z

src/java.base/share/classes/sun/nio/ch/SelectionKeyImpl.java


-    private final SelChImpl channel;
-    private final SelectorImpl selector;
+    protected final SelChImpl channel;


There is a public accessor for this, why does it need to be protected?

pshipton · 2025-12-12T03:49:33Z

src/java.base/share/classes/sun/nio/ch/SelectorImpl.java

 {
    // The set of keys registered with this Selector
-    private final Set<SelectionKey> keys;
+    protected final Set<SelectionKey> keys;


Why do these need to be protected? This and selectedKeys.

shruacha1234 force-pushed the PollsetSelectorImpl branch 2 times, most recently from 7ecd733 to 775e2a7 Compare December 8, 2025 05:51

sruthyjay force-pushed the PollsetSelectorImpl branch from 23cc4cc to 7db7191 Compare December 8, 2025 11:02

shruacha1234 force-pushed the PollsetSelectorImpl branch from 7db7191 to a940f39 Compare December 9, 2025 09:42

pshipton reviewed Dec 9, 2025

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src/jdk.net/share/classes/jdk/nio/Channels.java Outdated Show resolved Hide resolved

shruacha1234 force-pushed the PollsetSelectorImpl branch 3 times, most recently from d51680e to b4a4bd0 Compare December 10, 2025 10:13

shruacha1234 force-pushed the PollsetSelectorImpl branch from b4a4bd0 to d16e09a Compare December 11, 2025 04:05

pshipton reviewed Dec 12, 2025

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Add PollsetSelector implementation to resolve the performance degradation #1000

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