IBM Support

PM19290: FLUSHHELPER THREAD CONSUMES ALL CPU ON PLATFORMS WITH NO THREAD PRIORITY BOOST

Fixes are available

7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for AIX
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for HP-UX
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for IBM i
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for Linux
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for Solaris
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for Windows
7.0.0.13: Java SDK 1.6 SR8FP1 Cumulative Fix for WebSphere Application Server
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for AIX
7.0.0.15: Java SDK 1.6 SR9 Cumulative Fix for WebSphere Application Server
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for HP-UX
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for IBM i
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for Linux
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for Solaris
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for Windows
7.0.0.17: WebSphere Application Server V7.0 Fix Pack 17
7.0.0.17: Java SDK 1.6 SR9 FP1 Cumulative Fix for WebSphere Application Server
7.0.0.19: WebSphere Application Server V7.0 Fix Pack 19
7.0.0.21: WebSphere Application Server V7.0 Fix Pack 21
7.0.0.23: WebSphere Application Server V7.0 Fix Pack 23
7.0.0.25: WebSphere Application Server V7.0 Fix Pack 25
7.0.0.27: WebSphere Application Server V7.0 Fix Pack 27
7.0.0.29: WebSphere Application Server V7.0 Fix Pack 29
7.0.0.31: WebSphere Application Server V7.0 Fix Pack 31
7.0.0.27: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.33: WebSphere Application Server V7.0 Fix Pack 33
7.0.0.35: WebSphere Application Server V7.0 Fix Pack 35
7.0.0.37: WebSphere Application Server V7.0 Fix Pack 37
7.0.0.39: WebSphere Application Server V7.0 Fix Pack 39
7.0.0.41: WebSphere Application Server V7.0 Fix Pack 41
7.0.0.43: WebSphere Application Server V7.0 Fix Pack 43
7.0.0.45: WebSphere Application Server V7.0 Fix Pack 45
7.0.0.19: Java SDK 1.6 SR9 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.21: Java SDK 1.6 SR9 FP2 Cumulative Fix for WebSphere
7.0.0.23: Java SDK 1.6 SR10 FP1 Cumulative Fix for WebSphere
7.0.0.25: Java SDK 1.6 SR11 Cumulative Fix for WebSphere Application Server
7.0.0.27: Java SDK 1.6 SR12 Cumulative Fix for WebSphere Application Server
7.0.0.29: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.45: Java SDK 1.6 SR16 FP60 Cumulative Fix for WebSphere Application Server
7.0.0.31: Java SDK 1.6 SR15 Cumulative Fix for WebSphere Application Server
7.0.0.35: Java SDK 1.6 SR16 FP1 Cumulative Fix for WebSphere Application Server
7.0.0.37: Java SDK 1.6 SR16 FP3 Cumulative Fix for WebSphere Application Server
7.0.0.39: Java SDK 1.6 SR16 FP7 Cumulative Fix for WebSphere Application Server
7.0.0.41: Java SDK 1.6 SR16 FP20 Cumulative Fix for WebSphere Application Server
7.0.0.43: Java SDK 1.6 SR16 FP41 Cumulative Fix for WebSphere Application Server

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APAR status

  • Closed as program error.

Error description

  • Using the Service Integration Bus (SIB) filestore on operating
    systems that utilize a CPU scheduler that has no thread
    priority boost, a thread named "FlushHelper" can consume all
    the CPU.  This causes an apparent hang.
    
    No default configuration of the WebSphere Application Server
    supported platforms have a CPU scheduler with no priority boost.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  Users of the default messaging provider for *
    *                  IBM WebSphere Application Server Version 7  *
    *                  using a file store as the message store     *
    *                  for a messaging engine                      *
    ****************************************************************
    * PROBLEM DESCRIPTION: On a platform with a CPU scheduler      *
    *                      that does not support priority boot,    *
    *                      an apparent hang might occur showing    *
    *                      a thread called 'FlushHelper' using     *
    *                      all CPU                                 *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    The FlushHelper thread is part of the persistent
    logger of the service integration bus file store.
    The persistent logger is a component that is also used in
    other IBM products, where it is referred to as 'Object Manager'.
    
    The FlushHelper thread has a priority of (normal + 1) so on
    operating system with a single CPU that utilize a CPU scheduler
    with no thread priority boost or this feature is disabled, the
    FlushHelper thread can enter a state where it starves other
    threads.
    Normal priority threads deliver work to the FlushHelper.   If
    a particular thread interleaving occurs it is possible that a
    normal priority thread delivering work can be interrupted by
    the FlushHelper thread, which loops waiting for the normal
    priority thread to complete delivery of the work.
    
    No priority boost means the normal priority thread will never
    complete the few instructions remaining to allow the
    FlushHelper to do the work and relinquish the CPU.
    
    No default configuration of the WebSphere Application Server
    supported platforms have a CPU scheduler with no priority boost.
    

Problem conclusion

  • The fix for this APAR updates the FlushHelper to extend
    existing synchronization to ensure threads delivering work
    complete before the FlushHelper attempts to process that work.
    
    The fix for this APAR is currently targeted for inclusion in
    fix pack 7.0.0.13.  Please refer to the Recommended Updates
    page for delivery information:
    http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
    

Temporary fix

Comments

APAR Information

  • APAR number

    PM19290

  • Reported component name

    PLAT MSG COM

  • Reported component ID

    620800101

  • Reported release

    300

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-07-27

  • Closed date

    2010-07-30

  • Last modified date

    2010-07-30

  • 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

    PLAT MSG COM

  • Fixed component ID

    620800101

Applicable component levels

  • R300 PSY

       UP



Document information

More support for: WebSphere Application Server
Service Integration Technology

Software version: 7.0

Reference #: PM19290

Modified date: 30 July 2010