IBM Support

IJ07755: SOCKET COMMUNICATION OVER NIO IN AIX CAUSES HIGH CPU EVEN THOUGH THE CONNECTION IS IDLE.

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APAR status

  • Closed as program error.

Error description

  • Error Message: N/A
    .
    Stack Trace: The high cpu threads hold the following stack.
    at sun/misc/Unsafe.park(Native Method)
    at
    java/util/concurrent/locks/LockSupport.park(LockSupport.java:198
    (Compiled Code))
    at
    java/util/concurrent/locks/AbstractQueuedSynchronizer$ConditionO
    bject.await(AbstractQueuedSynchronizer.java:2055(Compiled Code))
    
    at
    java/util/concurrent/ArrayBlockingQueue.take(ArrayBlockingQueue.
    java:386(Compiled Code))
    
    at
    sun/nio/ch/UnixEventPort$EventHandlerTask.run(UnixEventPort.java
    :277(Compiled Code))
    
    at
    sun/nio/ch/AsynchronousChannelGroupImpl$1.run(AsynchronousChanne
    lGroupImpl.java:125)
    
    at
    java/util/concurrent/ThreadPoolExecutor.runWorker(ThreadPoolExec
    utor.java:1157(Compiled Code))
    
    at
    java/util/concurrent/ThreadPoolExecutor$Worker.run(ThreadPoolExe
    cutor.java:627)
    
    at java/lang/Thread.run(Thread.java:809)
    .
    

Local fix

Problem summary

  • The problem is caused due to a bug in the poll mechanism which
    keeps returning the same event registered again and again until
    it is processed. Due to this the worker threads are interrupted
    with nothing to process, resulting in increased cpu usage.
    

Problem conclusion

  • The JVM has been updated to reset the event in the events list
    when ever it is returned.
    .
    This APAR will be fixed in the following Java Releases:
       8    SR5 FP20  (8.0.5.20)
       7 R1 SR4 FP30  (7.1.4.30)
       7    SR10 FP30 (7.0.10.30)
    .
    Contact your IBM Product's Service Team for these Service
    Refreshes and Fix Packs.
    For those running stand-alone, information about the available
    Service Refreshes and Fix Packs can be found at:
               https://www.ibm.com/developerworks/java/jdk/
    

Temporary fix

Comments

APAR Information

  • APAR number

    IJ07755

  • Reported component name

    JAVA CLASS LIBS

  • Reported component ID

    620700130

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2018-07-11

  • Closed date

    2018-07-23

  • Last modified date

    2018-07-23

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    JAVA CLASS LIBS

  • Fixed component ID

    620700130

Applicable component levels



Document information

More support for: Runtimes for Java Technology
Java Class Libraries

Software version: 800

Reference #: IJ07755

Modified date: 23 July 2018