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OA50806: JES2 HIGH CPU IN IAXIS AT HJE77A0 RSM SUPPORT FOR OA50777

A fix is available

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APAR status

  • Closed as program error.

Error description

  • In HJE77A0 JES2 was changed to moved some of the data areas
    associated with CKPT processing from 31 to 64-bit storage.
    Correspondingly, JES2 also changed the way it creates and
    manages checkpoint versions (CKVR).
    
    Specifically, HASPCKVR makes use of IARVSERV CHANGEACCESS and
    SHARE  requests.  Due to the characteristics of the pages being
    shared, it is driving a large number of VIEWADD and VIEWDEL
    requests within IAXIS.  This causes an increase in CPU
    utilization within the JES2 address space.
    
    KNOWN IMPACT:
    Increased CPU utilization by the JES2 address space (within
    IAXIS module)
    
    VERIFICATION STEPS:
    1) Report monitors can show increased CPU utilization by JES2 at
       HJE77A0
    2) RSM IARVSERV ctrace run against JES2 address space will show
       a very large number of CHANGEACCESS entries followed by a
       very large number of VIEWDEL and VIEWADD entries
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of HBB77A0 and HJE77A0.            *
    ****************************************************************
    * PROBLEM DESCRIPTION: High CPU in IAXIS in JES2 address       *
    *                      space.                                  *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    This fix is in support of JES2 APAR OA50777.  In HJE77A0,
    JES2 added an additional IARVSERV CHANGEACCESS call in support
    of checkpoint versioning because IARVSERV SHARE is only
    allowed for WRITE mode views.  JES2 therefore had to change
    an entire copy of the JES2 checkpoint from READONLY to WRITE
    and back again in order to create a new checkpoint version.
    

Problem conclusion

  • Support is added to IARVSERV SHARE and IARVSERV UNSHARE for JES2
    to allow them to eliminate the CHANGEACCESS calls.
    

Temporary fix

  • *********
    * HIPER *
    *********
    

Comments

APAR Information

  • APAR number

    OA50806

  • Reported component name

    RSM - REAL STOR

  • Reported component ID

    5752SC1CR

  • Reported release

    7A0

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-06-27

  • Closed date

    2016-08-09

  • Last modified date

    2016-09-02

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

    OA50777

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

    UA82486

Modules/Macros

  • IARRCE   IARVSERV IAXCA    IAXCB    IAXCR
    IAXCW    IAXDO    IAXDR    IAXDT    IAXFB    IAXFG    IAXFP
    IAXFY    IAXGA    IAXIA    IAXID    IAXIS    IAXIU    IAXIV
    IAXIX    IAXLA    IAXM2    IAXPE    IAXPF    IAXPP    IAXPR
    IAXPU    IAXPZ    IAXVF
    

Fix information

  • Fixed component name

    RSM - REAL STOR

  • Fixed component ID

    5752SC1CR

Applicable component levels

  • R7A0 PSY UA82486

       UP16/08/24 P F608 Ž

Fix is available

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Document information

More support for: z/OS family

Software version: 7A0

Operating system(s): MVS, z/OS

Reference #: OA50806

Modified date: 02 September 2016