OA62027: WLM ALGORITHM UPDATE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• WLM algorithm update.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users of z/OS 2.4 (HBB77C0) and above.                   *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * WLM routing service IWMSRSRS returns                         *
  * a list of servers along with a                               *
  * relative weight for each server.  The                        *
  * weights are proportional to the                              *
  * amount of available capacity on each                         *
  * system.  The importance of the work                          *
  * to be routed is not considered, which                        *
  * can result in WLM assigning systems                          *
  * with a lot of low importance workload                        *
  * a small weight, even if the workload                         *
  * to be routed has a high importance.                          *
  * This may result in a workload                                *
  * distribution which is less effective                         *
  * compared to a distribution which                             *
  * considers the importance when                                *
  * determining displaceable capacity.                           *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The WLM Sysplex routing information service, IWMSRSRS returns
  a list of eligible servers with a weight assigned to each
  server.  The caller of IWMSRSRS can then route work
  based on the relative weight assigned to each server, where
  the higher weighted servers receive more work.  The weights
  are proportional to the amount of available CPU capacity on
  each system.  The IWMSRSRS service does not take the
  importance of the work to be routed into consideration.
  This may result in a workload distribution which is less
  effective compared to a distribution which considers the
  importance of the work being routed and how much work with
  lower importance can be displaced.
  

Problem conclusion

• WLM service IWMSRSRS is extended by a new SPECIFICIMP function.
  This function performs like the SPECIFIC function but also
  considers the importance of the work being handled by the
  eligible servers and how much other work with lower importance
  can be displaced. Thus, high important work could get
  distributed more evenly because the function will take into
  account systems with lots of lower important work.
  
  Sysevent ReqSrmSt enhancement with OA62027:  To determine
  whether WLM supports the new SPECIFICIMP function for IWMSRSRS,
  the SYSEVENT ReqSrmSt macro can be used. The parameter list
  (mapping macro IRASRMST) returns a new bit SrmStImp in field
  SRMSTFF3. If ON, the support is available.
  

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:

  UJ09349 UJ09350

Modules/Macros

• IWMW4SRS IRARMOPT IWMZ2COR IEAVNP10 IWMZ2VRY IRAPASPD IWMW4SR2
  IRAPAASC IWMW4SR1 IRASRMST IRAEVREQ IWMSRSRS IRAPASS1 IRARMFMP
  

Fix information

• Fixed component name

  WORK LOAD MANAG

• Fixed component ID

  5752SCWLM

Applicable component levels

• R7C0 PSY UJ09349

     UP22/10/12 P F210

• R7D0 PSY UJ09350

     UP22/10/12 P F210

Fix is available

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