II14219: DB2 Z/OS ZIIP EXPLOITATION "SUPPORT USE" INFORMATION.

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APAR status

  • Closed as canceled.

Error description

  • 5740XYR00 DB2ZIIP
    DB2 z/OS V8 zIIP exploitation "support use" information.
    KEYWORD: zIIP/K
    DB2 V8 zIIP APARs:
     PK30548 INCORRECT CALCULATION FOR WORKLOAD SHARING OR ABEND0C9
             DSNTTTC WHEN IBM ZIIP ENABLED FOR CP OR SYSPLEX
             PARALLELISM
             This allows PK27578 to also be applied.
     PK30087 REBUILD INDEX OF AN NPI WITH ZIIP EXPERIENCES 10%
             ELAPSED TIME DEGRADATION IN THE BUILD PHASE
     PK30474 zIIP UPDATES TO DSNWMSGS
     PK27712 DB2PM ACCOUNTING REPORTS SHOW HIGH CLASS 1 IIPCP TIME
             FOR UTILITY JOBS WITH ZIIP
     PK20487 DB2 UTILITY TOLERATION OF SPECIALTY ENGINES SUCH AS
             ICF, IFL, ZAAP, AND ZIIP
     PK19921 DB2 Z/OS EXPLOITATION OF THE IBM SYSTEM Z9 INTEGRATED
             D/T2094 INFORMATION PROCESSOR (IBM ZIIP) STAR SCHEMA
             PARALLEL QUERIES
     PK19920 DB2 Z/OS EXPLOITATION OF THE IBM SYSTEM Z9 INTEGRATED
             D/T2094 INFORMATION PROCESSOR (IBM ZIIP) FOR UTILITIES.
     PK18454 DB2 Z/OS EXPLOITATION OF THE IBM SYSTEM Z9 INTEGRATED
             D/T2094 INFORMATION PROCESSOR (IBM ZIIP) FOR DRDA
             THREADS
     PK37312 Correct invalid blank QWACWLME values.
     PK46171 Correct QWACASC (accumulated elapsed time).
     PM12256 zIIP related performance improvement.
    
    Support for zIIP related instrumentation changes in IFCIDs
    3,147,148,231,239 for zIIP usage reporting, monitoring and
    projection:
      PK25395, PK32787: IBM Tivoli OMEGAMON XE for DB2 Performance
        Expert on z/OS
      PK29966, PK32782: DB2 Performance Expert V210
      PK29967, PK32782: DB2 Performance Monitor V810
    
    A search on keyword zIIP/K will provide zIIP related
    APAR/PTF information for DB2 z/OS and other products
    as well.
    ---------------------------------------------------------------
    Question:
      What happens when zIIP processor is busy?
    Answer  :
      DB2 doesn't force an enclave to only run on a zIIP. If the
      zIIP is busy and it is not making its goal it will flow to a
      CP.  The zIIP eligible work that runs on a CP is shown as
      IIPCP in the RMF Workload Activity Report Service / Reporting
      classes an in the Omegamon DB2PE Accounting report CPU
      section. IIP field shows the zIIP CPU usage.
    
    Sample RMF Workload activity report zIIP CPU related
    information:
      SERVICE TIMES  ---APPL %---
      CPU    110.3   CP      3.16
      SRB      0.0   AAPCP   0.00
      RCT      0.0   IIPCP   1.19
      IIT      0.0
      HST      0.0   AAP     0.00
      AAP      0.0   IIP     5.67
      IIP     70.9
    Refer to RMF Report Analysis publication for more details.
    
    Sample Omegamon DB2PE Accounting report zIIP CPU related
    information :
      AVERAGE       APPL(CL.1)  DB2 (CL.2)
      ------------  ----------  ----------
      ELAPSED TIME  2:08.01174  2:07.92387
       NONNESTED    2:08.01174  2:07.92387
       STORED PROC    0.000000    0.000000
       UDF            0.000000    0.000000
       TRIGGER        0.000000    0.000000
    
      CP CPU TIME    19.373768   19.365788
       AGENT          6.779348    6.771411
        NONNESTED     6.779348    6.771411
        STORED PRC    0.000000    0.000000
        UDF           0.000000    0.000000
        TRIGGER       0.000000    0.000000
       PAR.TASKS     12.594420   12.594377
    
       IIPCP CPU      2.813831         N/A
    
      IIP CPU TIME   35.886951   35.886951
    Refer to Omegamon DB2PE Report Reference publication for more
    details.
    ---------------------------------------------------------------
    Question:
      What are the considerations related WLM service class goals
      for parallel queries ?
    Answer  :
      When running parallel task each task runs as a separate
      enclave.  For local apps, they can now define WLM goals for
      each parallel thread or by default run under the priority of
      the calling app. For remote apps, they would still use the
      same goals classified for the main DDF thread.
      Each parallel task of the query accumulates service units,
      period switch is determined for each task, not the overall
      query.
    ---------------------------------------------------------------
    Question:
      What are the considerations for zparm settings for parallel
      queries ?
    Answer  :
      Existing zparm PARAMDEG (which sets the maximum number of
      degrees) controls the degree of parallelism. Refer to DB2
      installation manual for details.
      Parallelism implies multiple tasks, so a single task is
      actually a sequential query which does not qualify for
      parallelism. When trying to exploit CP query parallelism, you
      cannot set the degree to 1 because DB2 does not choose
      parallelism since you need at least 2 degrees.
    ---------------------------------------------------------------
    Question:
      Is there a way to estimate or project the zIIP usage prior to
      installing zIIP hardware?
    Answer  :
      Customers who have installed the z/OS and DB2 V8 zIIP support
      software can set the SYS1.PARMLIB(IEAOPTxx) parm
      PROJECTCPU=YES. With this setting the RMF Workload activity
      report and DB2PE Accounting report IIPCP field will show the
      projected zIIP eligible CPU information. In the RMF workload
      activity report, look at the DDF work service class. For
      Utilities and Parallel queries setup proper WLM reporting
      Classes.
      For using DB2PE Accounting report, run reports for CONNTYPE
      DRDA and Utility.
      For parallel queries, run report for their plan or package
      names.
    
    Customers who are on DB2 V7 and need to estimate the DRDA zIIP
    redirect benefit can follow the following procedure :
      Ensure that WLM policy is setup with Service Class(es) for
      SUBSYSTEM TYPE=DDF Run the RMF Workload activity report
      (SYSRPTS) for the peak periods of interest showing DB2 DDF
      work related Service and Reporting Classes. The APPL% CP
      under the DDF work Service or Reporting Class(es) for the DB2
      Subsystem can be used to determine the DB2 enclave SRB CPU
      eligible to be redirected.
      Portion of the eligible work will be redirected to zIIP. If
      the eligible work is significant, contact IBM Tech Line/FTSS
      to help with the estimation for DRDA zIIP redirect.
      Indicate whether Stored Procedure and/or UDF (User Defined
      Function) are used extensively.
    
    Following is the procedure to estimate zIIP eligible CP time
    for Parallel Queries on DB2 V7:
      Gather DB2 Accounting trace Class(1,2,3) for the period of
      interest.
      Run Accounting report using a tool such as DB2PM / DB2PE
      excluding Connect Type Utility.
      If the average Class 2  PAR.TASKS  field in the Grand Total
      section has significant value (> 50 ms) then there may be a
      potential for zIIP redirect.
      - Run Accounting Trace.
      - Using DB2PE performance database or another tool, filter
        the queries that use more 100 ms of PAR.TASKS CPU
      - Subtract 0.1 Sec * number of parallel groups executed for
        each query
      - Sum the result for all such parallel queries
      - Significant portion of the result will be eligible for zIIP
        redirect
    More V8 parallelism potential with parallel sort and parallel
    multi column merge join.
    
    Following is the rule of thumb for potential zIIP redirect DB2
    Class 1 CPU savings for DB2 V7 Utilities for a configuration
    with 4 CPs, 2 zIIPs with fixed length Index keys:
      5 to 20% for Rebuild Index
      10 to 20% for Load or Reorg of a partition with one index
        only, or Load of entire table, or Reorg of entire
        tablespace
      40% for Rebuild Index of logical partition of non
        partitioning index
      40 to 50% for Reorg Index
      30 to 60% for Load or Reorg of a partition with more than one
      index
    ------------------------------------------------------------
    Considerations from a z/OS perspective:
    IIPHONORPRIORITY=YES is meant to route some of the
    zIIP-eligible work to standard CPs when the zIIP is heavily
    loaded. If it is set to NO, and the zIIP is heavily loaded you
    may reach a slowdown situation.  It may appear that DB2 is the
    problem and hogging cpu resources.
    ZIIPAWMT concerns the weight the zIIP processor is given on
    a customer's LPAR.
    Review APAR OA25825/UA42949 and ensure it is applied.
    IPHONORPRIORITY
    ---------------------------------------------------------------
    

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

  • Informational APAR.
    

APAR Information

  • APAR number

    II14219

  • Reported component name

    PB LIB INFO ITE

  • Reported component ID

    INFOPBLIB

  • Reported release

    001

  • Status

    CLOSED CAN

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2006-09-07

  • Closed date

    2006-09-08

  • Last modified date

    2011-07-21

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

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

Fix information

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Document information


More support for:

z/OS family

Software version:

001

Operating system(s):

MVS

Reference #:

II14219

Modified date:

2011-07-21

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