PM60830: IMS DRA OPEN THREAD PERFORMANCE OTT THREAD SAFE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• DRA Open Thread performance issues.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All IMS V12 CCTL users exploiting DRA Open   *
  *                 Thread. This includes CICS 4.2 users.        *
  ****************************************************************
  * PROBLEM DESCRIPTION: Performance degredation issues          *
  *                      specifically encountered by CICS TS 4.2 *
  *                      users that exploit threadsafe for       *
  *                      IMS DRA threads.                        *
  ****************************************************************
  * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
  ****************************************************************
  Two significant performance degredation issues are addressed:
  1. DFSPRRC0 and DFSPAT10 are issuing GETMAIN and FREEMAIN for
     every DRA thread request.
  2. A WLM Performance Block (PB) is obtained and released every
     PSB schedule.
  
  Additional issues:
  Thread hung in create thread, schedule PSB proessing. The save
  flow contains the following module flow:
  DFSDASC0 -> DFSDASP0 -> DFSDBLM0 -> DBFINTE0 -> DFSISWIT
  The TCB is waiting to be resumed by ISWITCH TO=RET that has
  already been done. However, the thread dispather work area
  contains the wrong TCB.
  

Problem conclusion

• GEN:
  KEYWORDS:
  
  *** END IMS KEYWORDS ***
  Performance issue 1 solution:
  =============================
  Reduction of GETMAIN and FREEMAIN calls from DFSPRRC0 and
  DFSPAT10.
  DFSPRRC0 will build and utilize cell pool storage for itself
  Module and Macro changes supporting this change:
  DFSPRRC0 - Build and utilize cell pool storage for itself
             as well as provide the needed storage for DFSPAT10.
  DFSPAT10 - Set compiler option to specify DFSPRCST gets module
             storage.
  
  DFSPAC   - Add CPOOL storage ID field
  
  
  Performance issue 2 solution:
  =============================
  Eliminate calling WLM to obtain and release PBs for every PSB
  schedule.
  Obtain a pool of WLM performance blocks during connection
  to IMS processing for DRA Open Thread environment.
  Threads will claim a PB from the pool during signon
  and only release it at signoff or abnormal thread termination.
  
  
  IMSAUTH  - add WLM_PBPOOL function code x'84'
           New return codes for WLM_PBPOOL:
           RC  - Meaning
           04    Caller is not under the TCB that issued IDENTIFY.
           08    Dependent Region Directory block not located.
           0C    Region IDENTIFY block not found.
           10    Call made from unsupported region type.
           14    Invalid function request.
           20    Create caller not authorized
           24    Second Create PB Pool is not allowed.
           28    Failed to get storage for DFSWLMPP block.
           2C    WLM Get PB blocks failed for CREATE request.
           40    No PB Pool block was located for ADD request.
           44    ADD request not issued from same TCB as CREATE.
           48    Failed to get storage for ADD PBs request.
           4C    WLM Get PB blocks failed for ADD request.
           60    DELETE caller is not authorized.
  
  DFSV4200 - add WLM_PBPOOL function, CREATE, ADD and DELETE
           CREATE subfunction - Get PB Pool header, DFSWLMPP.
             Obtain initial pool of PBs. The PBCOUNT is equal
             to min + max thread.
           ADD subfunction - Get additional PBCOUNT PBs
           DELETE subfunction - Delete all PBs and related
             PB pool storage
  
  DFSAERI0, DFSPRA10 - Add MAXTHD to DFSSSOB IDENTIFY call
  DFSDASI0 - Issue IMSAUTH WLM_PBPOOL CREATE during IDENTIFY
             processing.
             Module is converted to use branch relative.
  DFSDASS0 SIGNON - Claim PB from pool during signon processing.
             If no PBs are available, set signon feedback and
             defer PB claim to PSB schedule.
           SIGNOFF - Return pool PBs to the pool for reuse.
  
  DFSPINI0 - Check signon feedback for PBs needed and enqueue
             request more PBs to DRA control routine DFSPRRA0.
  DFSDASP0 - Claim PB from pool is needed, set schedule feedback
             if more PBs needed. If no PBs are available from the
             pool, issue DFSWLME call to obtain one.
  DFSPSCH0 - Check schedule PSB feedback for PBs needed and
             enqueue request to DRA control.
  DFSDAST0 - Delete WLM PB for DRA Open Thread if not obtained
             from the pool
  DFSDTTA0 - Reset flag bits in DFSWLMWK.
  DFSDASD0 - Issue IMSAUTH DELETE during Terminte Identify call
             processing.
  DFSPRRA0 - Add routine to issue IMSAUTH ADDPB
  
  DBFDBF00 - Recompile for DFSSSOB changes to CNBA offset
  
  DFSDPDIR - Add anchor pointer DPPBPOOL for DFSWLMPP block
  DFSPQE   - Add PQE function to request additional PB pool
  DFSSSOB  - Add MAXTHD= parameter for IDENTIFY function.
             Relocated SSPICNBA.
  DFSTRSOB - Updated SSOB byte trace with codes for PB pool
             diagnostic trace codes.
  DFSWLME  - Add PBPOOL request to obtain a pool of PB from WLM
  DFSWLML  - Add PBPOOL support to delete PB by address
  DFSWLMPP - New macro defines the WLM PB pool blocks.
  
  
  Hung thread in PSB schedule.
  ============================
  DFSDASC0 - Update the dispatcher workarea with the current TCB
             for DRA Open Thread calls.
  
  
  Updates to IMS V12 documentation:
  
  GC189715xx  Messages and Codes, Volume 4: IMS Component Codes
  Chapter 2:  IMS system services return codes
  Section: IMSAUTH return codes
  Subsection: IMSAUTH WLM_PBPOOL (84)
  ---------------------------------------------------------------
   Return Code - Meaning
   04            Caller is not under the TCB that issued IDENTIFY.
   08            Dependent Region Directory block not located.
   0C            Region IDENTIFY block not found.
   10            Call made from unsupported region type.
   14            Invalid function request.
   20            Create caller not authorized
   24            Second Create PB Pool is not allowed.
   28            Failed to get storage for DFSWLMPP block.
   2C            WLM Get PB blocks failed for CREATE request.
   40            No PB Pool block was located for ADD request.
   44            ADD request not issued from same TCB as CREATE.
   48            Failed to get storage for ADD PBs request.
   4C            WLM Get PB blocks failed for ADD request.
   60            DELETE caller is not authorized.
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

• POSTREQ PM97386
  PINNED RP13/09/18 (ATXT) TO ADD POSTREQ PM97386 INFO.
   **** PE13/09/18 PTF IN ERROR. SEE APAR PM97386 FOR DESCRIPTION.
  ×**** PE13/09/19 FIX IN ERROR. SEE APAR PM97386  FOR DESCRIPTION
  

APAR Information

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

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

  UK81843

Modules/Macros

•    DBFDBF00 DFSAERI0 DFSDASC0 DFSDASD0 DFSDASI0
  DFSDASP0 DFSDASS0 DFSDAST0 DFSDPDIR DFSDTTA0 DFSPAPL  DFSPAT10
  DFSPINI0 DFSPRA10 DFSPRP   DFSPRRA0 DFSPRRC0 DFSPSCH0 DFSSSOB
  DFSTRSOB DFSV4200 DFSWLME  DFSWLML  DFSWLMPP DFSWLMWK IMSAUTH
  

Fix information

• Fixed component name

  IMS V12

• Fixed component ID

  5635A0300

Applicable component levels

• R200 PSY UK81843

     UP12/09/18 P F209 Ž

Fix is available

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