Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• New Function
  WLM Importance Based Initiator Dispatching Priority Control
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of OS/390 R10 (HBB7703) and above      *
  ****************************************************************
  * PROBLEM DESCRIPTION: When running in compatibility mode,     *
  *                      initiators are assigned the dispatching *
  *                      priority that is specified by the       *
  *                      PVLDP keyword in the IEAIPSxx parmlib   *
  *                      member. In goal mode, initiators run    *
  *                      in service class SYSSTC with a fixed    *
  *                      dispatching priority of 254 and there   *
  *                      is no way to adjust or change the       *
  *                      dispatching priority. The work running  *
  *                      under the initiator is assigned its     *
  *                      installation specified service class    *
  *                      during SYSEVENT JOBSELCT processing.    *
  *                      If there are cpu intensive exits that   *
  *                      run prior to job select processing, the *
  *                      work will run at dispatching priority   *
  *                      254 and this can potentially impact     *
  *                      high importance work.                   *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When running in goal mode, there may be rare cases where it is
  necessary to be able to adjust the dispatching priority of
  initiators so that cpu intensive exits running prior to job
  select do not impact high importance work.
  

Problem conclusion

Temporary fix

Comments

• A new parameter INITIMP in the IEAOPTxx member of SYS1.PARMLIB
  has been defined to allow an installation to set the initiator
  dispatching priority. The new dispatching priority applies to
  JES, APPC and OMVS initiators.
  Parameter INITIMP can be set as follows:
  - INITIMP=0
    is the same as if the parameter hasn't been defined.
    The initiator dispatching priority is set to 254.
  - INITIMP=1,2, or 3
    defines that the initiator dispatching priority has to be
    lower than the dispatching priority for cpu critical work
    with the same or a higher importance level.
    If no service class with the cpu critical attribute and a
    corresponding or higher importance level is defined in the
    WLM policy, the dispatching priority is calculated in the
    same way as for parameter INITIMP=E.
  - INITIMP=E
    defines that the initiator dispatching priority will be
    calculated in the same way as the enqueue promotion
    dispatching priority. The dispatching priority is calculated
    dynamically to ensure access to the processor. It should not
    impact high importance work, however there is no guarantee
    that cpu critical work will always have a higher dispatching
    priority.
  
  The default is INITIMP=0. So if the INITIMP parameter is not
  defined or if it is defined as INITIMP=0, all JES, APPC and OMVS
  initiators will run at dispatching priority 254 as they
  currently do today, ensuring that the current system behavior
  remains unchanged. Therefore, no  changes or updates to the OPT
  are necessary unless your installation requires the dynamic
  calculation of the initiator dispatching priority.
  
  If your installation requires the dynamic calculation of the
  initiator dispatching priority, you will need to specify the new
  parameter INITIMP in the IEAOPTxx member of SYS1.PARMLIB
  When specifying an INITIMP value, it will only affect the system
  it has been set on. You can activate a new OPT parmlib member
  with the SET command: SET OPT=xx.
  After specifying an INITIMP value,the initiator will still show
  a service class of SYSSTC but the dispatching priority will be
  based on the INITIMP setting.
   **** PE03/06/03 FIX IN ERROR. SEE APAR OA03581  FOR DESCRIPTION
  

APAR Information

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

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

  UA01312 UA01313 UA01314 UA01315 UA01318

Modules/Macros

•    IEAVNP10 IEEMB812 IRACPUDP IRAEVREQ IRAOLST
  IRAPAPPP IRARMCTY IRARMEVT IRARMOPT IRARMSOP IRASETNP JBB7713J
  

Publications Referenced

SA22759200

Fix information

• Fixed component name

  5752 SYS RSRCE

• Fixed component ID

  5752SC1CX

Applicable component levels

• R703 PSY UA01312

     UP03/04/05 P F304

• R705 PSY UA01313

     UP03/03/19 P F304

• R706 PSY UA01314

     UP03/03/19 P F304

• R707 PSY UA01315

     UP03/03/19 P F304

• R713 PSY UA01318

     UP03/04/05 P F304

Fix is available

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Product categories:

Software

Operating System

z/OS family

APARs - z/OS environment

Operating system(s):

MVS, z/OS

Software version:

705

Reference #:

OW55344

IBM Group:

IBM Server Group

Modified date:

2003-07-10