PM83695: ZUDFM CAN CTL-10 DUE TO LODIC

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APAR status

  • Closed as program error.

Error description

  • See Problem Summary.
    

Local fix

  • na
    

Problem summary

  • APAR NUMBER:  PM83695
    PRODUCT:  z/TPFDF
    FUNCTIONAL AREA:  TPFDF ZUDFM ROUTINES
    SHIPPED IN PUT:  10
    
    ABSTRACT:
    ZUDFM INIT id NOHOLD processing, introduced by APAR PM26537,
    can drive up CPU utilization to 100 percent, potentially
    preventing deferred ECBs from being serviced.
    
    PACKAGE CONTENTS:
    Source Segments:
    (C) tpfdf/rt/ufd1.asm
    (C) tpfdf/macro/dfdfrc.mac
    
    Object Only Binaries:
    None.
    
    Configuration Independent Binaries:
    None.
    
    Support Files:
    None.
    
    OTHER BINARIES TO BUILD: YES
    (C) <sys>/obj/ufd1.o
    (C) <sys>/load/UFD1.so
    
    COMMENTS:
    ZUDFM INIT id NOHOLD issues a DLAYC after initializing 20
    ordinals to prevent CTL-10s from occurring. The DLAYC macro
    places the ECB on the input list, potentially preventing the
    DEFER list from being processed. This can drive up the CPU
    utilization to 100 percent and prevent other lower priority
    lists on the CPU loop from dispatching ECBs. Additionally,
    ZUDFM INIT id NOHOLD defers when a LODIC check fails. The LODIC
    checks just IOBs and uses a high priority resource class
    (IBMHI) when additional system resoruces should be checked and
    a lower priority class should be used for a utility function.
    Futhermore, system resources are not being checked after
    returning from issuing the DLAYC.
    

Problem conclusion

  • SOLUTION:
    A new assembler system services macro has been introduced -
    DFDFRC (dfdfrc.mac). This macro will defer an entry control
    block (ECB) when the ECB is within 100 milliseconds of an
    application timeout (CTL-10 system error).
    
    The ZUDFM INIT id NOHOLD processing in ufd1.asm has changed as
    follows:
    - Instead of issuing a DLAYC every 20 ordinals, a DFDFRC macro
    will be issued. The ECB will now be put on the deferred list
    instead of the input list while still preventing the CTL-10.
    - The LODIC now checks more system resources (IOB,FRM,SWB) and
    uses a lower priorty class (IBMBATCH) before deferring.
    Additionally, system resources are checked after the ECB is
    deferred.
    
    COREQS: NO
    None.
    
    MIGRATION CONSIDERATIONS: YES
    Application programming interface (API) changes:
    New assembler system services API - DFDFRC
    
    
    
    BUILD COMMANDS AND INSTRUCTIONS: YES
    #maketpf commands for linux
    maketpf -f UFD1 ufd1.o
    maketpf UFD1 link
    
    UPDATED INFORMATION UNITS: YES
    z/TPFDF Programming Concepts and Reference
    
    See your IBM representative if you need additional information.
    
    DOWNLOAD INSTRUCTIONS:
    http://www.ibm.com/software/htp/tpf/maint/maintztpf.html
    
    APAR URL:
    http://www.ibm.com/software/htp/tpf/ztpfmaint/put10/PM83695.htm
    

Temporary fix

Comments

APAR Information

  • APAR number

    PM83695

  • Reported component name

    ZTPFDF

  • Reported component ID

    5748F1501

  • Reported release

    110

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-02-26

  • Closed date

    2013-05-08

  • Last modified date

    2013-05-08

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

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

Publications Referenced
SK2T8062        

Fix information

  • Fixed component name

    ZTPFDF

  • Fixed component ID

    5748F1501

Applicable component levels

  • R110 PSY

       UP



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Document information


More support for:

TPF
z/TPF

Software version:

110

Reference #:

PM83695

Modified date:

2013-05-08

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