PK84224: INCREASING CPU UTILIZATION, PERFORMANCE DEGRADATION, DGOVDS, VSMLOC, LARGE NUMBER OF DQE CONTROL BLOCKS IN ADDRESS SPACE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• User experiences higher CPU on PR03system.
  Inspect reveals.
  +<.:  %CPU Utilization (TCB)
  |----+---10---+---20---+---30---+---40---+---50>
  + 274 00972088 DGOVDS    14.845|============>
  
  
  HIGH CPU
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: OMEGAMON XE for DB2 PE/DB2PM                 *
  *                 users of component:                          *
  *                 -   OMEGAMON collector                       *
  *                 -   PE Server subtask                        *
  ****************************************************************
  * PROBLEM DESCRIPTION: High CPU utilization problem caused by  *
  *                      DGOVDS, a module of PE Server subtask.  *
  *                      At the same time large number of DQE    *
  *                      blocks is growing and not released.     *
  ****************************************************************
  * RECOMMENDATION: Apply this PTF                               *
  ****************************************************************
  PROBLEM SUMMARY:
  The DGOVDS module uses the VSMLOC macro to verify
  whether certain storage addresses were already
  allocated using the GETMAIN or STORAGE macros in the
  private area storage of the current address space.
  Performance is directly related to the number of VSM
  Descriptor Queue Element  (DQE) blocks created to
  track storage usage in the address space.When there
  is a large number of such blocks created in the address
  space, all the DQEs are chained every time when VSMLOC
  is called. This process of scanning can hold the local
  address space suspend lock and cause enormous CPU
  utilization. This problem can be detected by e.g. the
  OMEGAMON for MVS INSPECT command which would show that
  the CSECT IGVSLOC related to DGOVDS is a hotspot.
  
  PROBLEM CONCLUSION:
  Use of VSMLOC has been replaced by use of the TPROT instruction
  to check validity of a certain storage area.
  

Problem conclusion

• Use of VSMLOC has been replaced by use of the TPROT instruction
  to check validity of a certain storage area.
  
  KEYWORDS :
  HIGH CPU USAGE CONSUMPTION UTILIZATION DGOVDS VSMLOC DQE
  

Temporary fix

Comments

APAR Information

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

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

  UK46688

Modules/Macros

• DGOVABND DGOVDS   DGOVHMM1 DGOVISI  DGOVMSTR
  DGOVPIG0 FPEVREQ0 FPEVTMEM HKDB410J KDB410J
  

Fix information

• Fixed component name

  OM XE DB2PE/PM

• Fixed component ID

  5655OPE00

Applicable component levels

• R410 PSY UK46688

     UP09/05/23 P F905

Fix is available

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