A fix is available
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 HJE77A0. * **************************************************************** * PROBLEM DESCRIPTION: JES2 checkpoint versions processing may * * unexpectedly consume a greater amount * * of CPU in the JES2 address space. * **************************************************************** * RECOMMENDATION: * **************************************************************** In z/OS 2.2 JES2 (HJE77A0), when checkpoint data areas were moved from 31-bit to 64-bit storage, JES2 changed the way it creates and manages checkpoint versions: Specifically, HASPCKVR, the Checkpoint Version Subtask, was changed to invoke the IARVSERV (RSM Virtual Storage Services) macro to perform CHANGEACCESS requests and additional SHARE requests. Due to the characteristics of the pages being shared, these added requests resulted in an unexpected increase in the amount of processing performed by the IAXIS module, causing an increase in CPU utilization within the JES2 address space.
Problem conclusion
TYPE/RESTART (HOT) IPL/REQUIRED (NO) CLPA (NO). Via RSM APAR OA50806, IARVSERV macro support has been changed to allow SHARE and UNSHARE operations against target virtual storage pages that may be read only. Using this new IARVSERV support, HASPCKVR, the Checkpoint Version Subtask, has been changed to remove IARVSERV CHANGEACCESS invocations that are no longer necessary preceding IARVSERV SHARE and UNSHARE invocations. As a result of these changes, CPU utilization by HASPCKVR processing is significantly reduced. **************************************************************** * * * For this APAR fix to be effective, the RSM APAR OA50806 * * fix must also be applied. * * * **************************************************************** APAR OA50777 prereq's (and sup's) for FMID HJE77A0: Pre's: * NONE *
Temporary fix
*** * TEMPORARY FIX MAY BE OBTAINED FROM DLL OR INFO/ACCESS **** ******************* OA50777 DECK AVAILABLE ********************
Comments
APAR Information
APAR number
OA50777
Reported component name
JES2
Reported component ID
5752SC1BH
Reported release
7A0
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
YesSpecatt / Pervasive / Xsystem
Submitted date
2016-06-27
Closed date
2016-08-08
Last modified date
2016-09-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
OA50806 UA82420
Modules/Macros
HASPCKVR
Fix information
Fixed component name
JES2
Fixed component ID
5752SC1BH
Applicable component levels
R7A0 PSY UA82420
UP16/08/24 P F608
Fix is available
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Document Information
Modified date:
02 September 2016