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

Obtain the fix for this APAR.

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 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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