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PM49485: IMPROVE THE PERFORMANCE OF THE JIT COMPILER BY PROVIDING STARTUP AND SHUTDOWN HINTS.

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APAR status

  • Closed as program error.

Error description

  • Performance improvement for server startup.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server V8.0                                 *
    ****************************************************************
    * PROBLEM DESCRIPTION: Excessive JIT compilation increases     *
    *                      the start time of a WebSphere           *
    *                      Application Server for z/OS server.     *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    The Java JIT compiler provides a performance boost by
    compiling frequently used classes in such a way that future
    invocations of those classes perform better.  However, the
    initial compilation of these classes takes additional time.
    For classes that are used often throughout the life of the
    server, it is worth taking the initial time to compile them in
    order to obtain future performance benefits.
    During server startup, numerous classes are loaded that will
    rarely be invoked after startup is complete.  Compiling all of
    these classes is often unnecessary and can increase server
    start time.  The JIT compiler should be optimzied to avoid
    unnecessary compilations during server startup.
    

Problem conclusion

  • WebSphere Application Server for z/OS code was modified to
    inform the JIT compiler of the beginning and end of server
    startup.  The JIT compiler can use this information to make
    better decisions about which classes to compile, thereby
    improving server start time.
    
    APAR PM49485 is currently targeted for inclusion in
    Service Level (Fix Pack) 8.0.0.2 of WebSphere
    Application Server.
    
    Please refer to the Recommended Updates page for delivery
    information:
    http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
    
    In addition, please refer to URL:
    http://www.ibm.com/support/docview.wss?rs=404&uid=swg27006970
    for Fix Pack PTF information.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PM49485

  • Reported component name

    WEBSPHERE FOR Z

  • Reported component ID

    5655I3500

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-10-06

  • Closed date

    2011-10-11

  • Last modified date

    2012-08-09

  • 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

    WEBSPHERE FOR Z

  • Fixed component ID

    5655I3500

Applicable component levels

  • R800 PSY

       UP

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SS7K4U","label":"WebSphere Application Server for z\/OS"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"800","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
28 October 2021