OA22443: NEW FUNCTION -

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You can track all active APARs for this component.

APAR status

  • Closed as new function.

Error description

  • New function
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of z/OS 1.7.1 (JBB772S) and        *
    *                 above.                                       *
    ****************************************************************
    * PROBLEM DESCRIPTION: The default settings for WLM BLOCKED    *
    *                      WORKLOAD Support (See APAR OA17735) are *
    *                      changed such that the function is       *
    *                      enabled by default.  Also the threshold *
    *                      that a blocked workload needs to wait   *
    *                      until being promoted is lowered.        *
    *                      Thirdly, the calculation of the amount  *
    *                      of CPU capacity that is used to help    *
    *                      blocked workload is adapted for z10.    *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    Prior to this change, the blocked workload support was disabled
    by default in releases z/OS R1.7.1 and z/OS R1.8 if the two
    parameters that regulate this function, BLWLTRPCT and BLWLINTHD,
    were not specified in the IEAOPT parmlib member.  With this
    apar, this will be changed such that the blocked workload
    function will be activated by default, even if the BLWLTRPCT and
    BLWLINTHD keywords are not specified in the OPT.  The default
    for BLWLINTHD is set to 20 seconds and the default for BLWLTRPCT
    is set to 5, which means 0.5% of the LPAR's CPU capacity.
    
    For release z/OS R1.9, prior to this change, the blocked
    workload support was enabled by default. With this apar, the
    default for BLWLINTHD changed from 60 to 20 seconds.
    
    Also, for all these releases the calculation of the amount of
    CPU capacity that is used to help blocked workload is adapted
    for z10.
    

Problem conclusion

  • D/T2098
    

Temporary fix

Comments

  • +--- Documentation to be updated ------------------------------+
    |                                                              |
    | z/OS 1.7:                                                    |
    |  SA22-7592-12 -- MVS Initialization and Tuning Reference     |
    |                                                              |
    | z/OS 1.8:                                                    |
    |  SA22-7592-14 -- MVS Initialization and Tuning Reference     |
    |                                                              |
    | z/OS 1.9:                                                    |
    |  SA22-7592-15 -- MVS Initialization and Tuning Reference     |
    |                                                              |
    |                                                              |
    +--- Location in Publication ----------------------------------+
    |                                                              |
    | z/OS 1.7:                                                    |
    |  SA22-7592-12 -- MVS Initialization and Tuning Reference     |
    |                                                              |
    | z/OS 1.8:                                                    |
    |   SA22-7592-14 -- MVS Initialization and Tuning Reference    |
    |                                                              |
    |   Chapter 43. IEAOPTxx (OPT parameters)                      |
    |     Statements/parameters for IEAOPTxx                       |
    |       New OPT parameter BLWLINTHD added                      |
    |                                                              |
    +--------------------------------------------------------------|
    | BLWLINTHD                                                    |
    | Specifies the threshold time interval for which a blocked    |
    | address space or enclave must wait before being considered   |
    | for promotion. If the CPU utilization of a system is at 100%,|
    | workloads with low importance (low dispatch priority) might  |
    | not get dispatched anymore. This can lead to problems if the |
    | low priority work holds a resource that is required by high  |
    | priority workloads. Therefore, if an address space or enclave|
    | has ready-to-run work units (TCBs or SRBs) but does not get  |
    | CPU service for the specified time interval because of its   |
    | low dispatch priority, it will be temporarily promoted to a  |
    | higher dispatch priority. Address spaces that are swapped out|
    | are not considered for promotion.                            |
    |                                                              |
    | The syntax is:                                               |
    |                                                              |
    | BLWLINTHD=option                                             |
    |                                                              |
    | Value Range: 5-65535 seconds                                 |
    |                                                              |
    | Default Value: 20 seconds                                    |
    +--------------------------------------------------------------|
    |   Chapter 43. IEAOPTxx (OPT parameters)                      |
    |     Statements/parameters for IEAOPTxx                       |
    |       New OPT parameter BLWLTRPCT added                      |
    |                                                              |
    +--------------------------------------------------------------|
    | BLWLTRPCT                                                    |
    | Specifies how much of the CPU capacity is to be used to      |
    | promote blocked workloads. This parameter does not influence |
    | the amount of CPU service that a single blocked address space|
    | or enclave is given. Instead, this parameter influences how  |
    | many different address spaces or enclaves can be promoted at |
    | the same point in time. If the value specified with this     |
    | parameter is not large enough, blocked workloads might need  |
    | to wait longer than the time interval defined by BLWLINTHD.  |
    |                                                              |
    | The syntax is:                                               |
    |                                                              |
    | BLWLTRPCT=option                                             |
    |                                                              |
    | Value Range:  0-200 (up to 20%. 0% implies that blocked      |
    |                      workloads should not be promoted.)      |
    | Default Value: 5 (0.5%)                                      |
    +--------------------------------------------------------------+
    +--- Location in Publication ----------------------------------+
    |                                                              |
    | z/OS 1.9:                                                    |
    |   SA22-7592-15 -- MVS Initialization and Tuning Reference    |
    |                                                              |
    |   Chapter 44. IEAOPTxx (OPT parameters)                      |
    |     Statements/parameters for IEAOPTxx                       |
    |       New OPT parameter BLWLINTHD added                      |
    |                                                              |
    +--------------------------------------------------------------|
    | BLWLINTHD                                                    |
    | Specifies the threshold time interval for which a blocked    |
    | address space or enclave must wait before being considered   |
    | for promotion. If the CPU utilization of a system is at 100%,|
    | workloads with low importance (low dispatch priority) might  |
    | not get dispatched anymore. This can lead to problems if the |
    | low priority work holds a resource that is required by high  |
    | priority workloads. Therefore, if an address space or enclave|
    | has ready-to-run work units (TCBs or SRBs) but does not get  |
    | CPU service for the specified time interval because of its   |
    | low dispatch priority, it will be temporarily promoted to a  |
    | higher dispatch priority. Address spaces that are swapped out|
    | are not considered for promotion.                            |
    |                                                              |
    | The syntax is:                                               |
    |                                                              |
    | BLWLINTHD=option                                             |
    |                                                              |
    | Value Range: 5-65535 seconds                                 |
    |                                                              |
    | Default Value: 20 seconds                                    |
    +--------------------------------------------------------------+
    
    Enhancement update
    -------------------
      For z/OS R1.9 the function has been enabled by default.
      With this APAR, the default value of BLWLINTHD is changed
      from 60 to 20 seconds.
    
      For z/OS R1.7.1 and z/OS R1.8 the function by default had
      been disabled. With this APAR, the function by default is
      enabled and in addition the default value of BLWLINTHD is
      changed from 60 to 20 seconds and the default value of
      BLWLTRPCT is changed from 0 to 5 (0.5% of the LPAR's CPU
      capacity).
      This APAR thus does change your system's behavior.
    
      If you do not want this change to become effective, you
      can disable the function by setting the new OPT parameter
      BLWLTRPCT to 0 in parmlib member IEAOPTxx.
    
    
      New function description:
        For a description of this new function and further more to
        understand the rationale and the implications of this
        function, please see the WSC Flash with the number
        FLASH10609.  In this WSC Flash it is also explained why
        IBM recommends that the function be enabled.
    
    Keyword: D/T2097
    

APAR Information

  • APAR number

    OA22443

  • Reported component name

    5752 SYS RSRCE

  • Reported component ID

    5752SC1CX

  • Reported release

    72S

  • Status

    CLOSED UR1

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2007-09-13

  • Closed date

    2008-04-24

  • Last modified date

    2008-10-31

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

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

    UA40607 UA40608 UA40609 UA40626

Modules/Macros

  • IRAOLST  IRAPASS1 IRARMCPM IRARMOPT
    

Publications Referenced
SA22759212 SA22759214 SA22759215    

Fix information

  • Fixed component name

    5752 SYS RSRCE

  • Fixed component ID

    5752SC1CX

Applicable component levels

  • R72S PSY UA40626

       UP08/05/14 P F805

  • R730 PSY UA40607

       UP08/05/14 P F805

  • R740 PSY UA40608

       UP08/05/14 P F805

  • R750 PSY UA40609

       UP08/05/29 P F805

Fix is available

  • Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.



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Document information


More support for:

z/OS family

Software version:

72S

Operating system(s):

MVS, z/OS

Reference #:

OA22443

Modified date:

2008-10-31

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