OA59967: IMPROVEMENTS TO MASDEF CYCLEMGT=AUTO

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Improvements to the JES2 PCE internal PAIN calculation will
  be made in this APAR to ensure more equitable checkpoint sharing
  in a JES2 MAS running with CYCLEMGT=AUTO.
  
  The APAR will also include some RAS enhancements to PERFDATA
  statistics.
  
  ANALYSIS:
  JES2 HOLD and DORMANCY values are dynamically changed by JES2 in
  CYCLEMGT=AUTO mode based on internal PCE PAIN calculations.  The
  internal PAIN calculation for some PCEs may be too high, thereby
  causing the member to obtain a larger (and/or more frequent)
  slice of CKPT cycle.  This can cause other MAS members (with
  smaller PAIN) to get smaller share of the CKPT cycle slice;
  thereby impacting JES2 throughput on those other members.
  
  
  KNOWN IMPACT:
  It is possible there is enough available CKPT in the cycle such
  that over-reporting of PAIN value on one member(s) will not be
  noticed nor impact overall JES2 performance.  However, an
  over-calculation of PAIN values on a MAS member(s) can cause
  performance problems on other members in the MAS.  This can
  impact the overall MAS throughput (such as JOB submission, etc).
  
  
  
  
  VERIFICATION STEPS:
  1) MAS running with MASDEF CYCLEMGT=AUTO
  2) One member in MAS reporting very large PAIN value resulting
  in excessive checkpoint access (AVGHOLD vs AVGDORM) negatively
  impacting other members
  

Local fix

• BYPASS/CIRCUMVENTION:
  If JES2 throughput is being greatly impacted, an installation
  may consider switching back to CYCLEMGT=MANUAL and manually
  adjusting each member HOLD and DORM values to (more) favor the
  member which was impacted.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users of HJE77A0, HJE77B0, and                           *
  * HJE77C0 with CYCLEMGT=AUTO specified.                        *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Improvements were made to CYCLEMGT=AUTO                      *
  * processing and additional diagnostic                         *
  * information was added (in HJE77C0).                          *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  CYCLEMGT=AUTO processing was updated in z/OS 2.4 (HJE77C0) to
  better deal with asymmetric JESPLEX environments (for example
  one member that does heavy input processing while another has
  heavy execution processing).  Unfortunately, not all the
  changes performed as expected in customer environments.  A
  number of the z/OS 2.4 changes were problematic and others
  had coding errors.
  
  In the process of studying the customer's environment, a
  problem was discovered in how pain was accumulated within
  $POSTXEQ.
  

Problem conclusion

• TYPE/RESTART (WARM) IPL/REQUIRED (YES) CLPA (YES)
  
  CLPA is needed only if HASCxxxx modules currently reside in
  the pageable link pack area (PLPA).
  
  The problematic changes made to the pain calculations in z/OS
  2.4 have been removed and the coding errors have been corrected.
  
  $POSTXEQ processing has been updated to not accumulate pain
  when being posted to select work (only when processing work).
  
  These changes should better balance the pain levels of each
  member and better calculate needed HOLD and DORMANCY values.
  
  Finally, to help resolve these problems, a number of small
  enhancements were made to the $D PERFDATA diagnostic command
  (primarily in HJE77C0) to report additional statistics.
  These include a new subscript of QGETSTAT to display $QGET
  performance information and additional output in CKPTSTAT
  section to display a MAS wide view of checkpoint tuning
  values.
  
  Application of this APAR across all members of the MAS is
  recommended to ensure consistency in checkpoint tunning.
  Until the APAR can be applied to all MAS members, setting
  CYCLEMGT=MANUAL may be required to address any tunning issues.
  
  APAR OA59967 prereq's (and sup's) for FMID HJE77A0:
  Pre's: IA47124 IA47321 IA50359
  
  APAR OA59967 prereq's (and sup's) for FMID HJE77B0:
  Pre's: BA52887
  
  APAR OA59967 prereq's (and sup's) for FMID HJE77C0:
  Pre's: CA57722 CA57976 CA58718
  

Temporary fix

• *** * TEMPORARY FIX MAY BE OBTAINED FROM DLL OR INFO/ACCESS ****
  ******************* OA59967  DECK AVAILABLE ********************
  

Comments

APAR Information

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

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

  UJ04325 UJ04326 UJ04337

Modules/Macros

• $JQRWORK HASPXCF  HASPXEQ  HASPSXIT HASPDYN  HASPSPIN HASPSTAB
  HASPSTAC HASPNUC  HASPCKPT HASMPERF HASPPSO  HASPJQS  $PERFCB
  HASPSASR HASPNST  HASLIPCS HASPIRA  HASMTABL HASIBLD  $SXADDR
  HASPEVTL $XREQ    $HASPEQU HASCSCAN HASPCNVT HASPTABS HASMSXAD
  

Fix information

• Fixed component name

  JES2

• Fixed component ID

  5752SC1BH

Applicable component levels

• R7A0 PSY UJ04337

     UP20/11/18 P F011

• R7B0 PSY UJ04325

     UP20/11/18 P F011

• R7C0 PSY UJ04326

     UP20/11/18 P F011

Fix is available

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