OA37550: NEW FUNCTION - COUPLING FACILITY CACHE STRUCTURE PERFORMANCE ENHANCEMENTS AND RAS IMPROVEMENTS

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• Performance improvements are needed for
  coupling facility cache structures to
  avoid flooding the coupling facility
  cache with changed data and avoid
  excessive delays and backlogs for
  cast-out processing.
  
  Verification of local cache controls
  for a coupling facility cache structure
  connector need to be performed during
  registration of connection interest in
  a data item to protect against lost cross-invalidation
  signals.
  
  Capabilities are needed to allow for
  capturing and collecting of extended
  diagnostic structure data from coupling
  facility structures that have
  encountered an error that are
  non-disruptive and performed in the
  background so system tasks are not hung
  and cache request completion is not
  delayed
  FIXCAT:  ZOS0204C/K
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users running z/OS V1R10 (HBB7750) and above *
  *                 in a parallel sysplex configuration          *
  *                                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Full function small programming         *
  *                      enhancement (SPE) for z/OS V1R12        *
  *                      (HBB7770) and V1R13 (HBB7780) includes  *
  *                      the following:                          *
  *                                                              *
  *                      Performance improvements are needed for *
  *                      coupling facility cache structures to   *
  *                      avoid flooding the coupling facility    *
  *                      cache with changed data and avoid       *
  *                      excessive delays and backlogs for       *
  *                      cast-out processing.                    *
  *                                                              *
  *                      Verification of local cache controls    *
  *                      for a coupling facility cache structure *
  *                      connector need to be performed during   *
  *                      registration of connection interest in  *
  *                      a data item to protect against lost     *
  *                      cross-invalidation signals.             *
  *                                                              *
  *                      Capabilities are needed to allow for    *
  *                      capturing and collecting of extended    *
  *                      diagnostic structure data from coupling *
  *                      facility structures that have           *
  *                      encountered an error that are           *
  *                      non-disruptive and performed in the     *
  *                      background so system tasks are not hung *
  *                      and cache request completion is not     *
  *                      delayed.                                *
  *                                                              *
  *                      To allow full functionality provided by *
  *                      the SPE on systems at HBB7770 and above *
  *                      in a sysplex containing systems at      *
  *                      levels prior to HBB7770 (e.g. HBB7760   *
  *                      and HBB7750), non-function coexistence  *
  *                      support MUST be installed on the        *
  *                      systems at levels prior to HBB7770.     *
  *                      The required coexistence support for    *
  *                      the lower level systems is provided by  *
  *                      PTFs included in this APAR.             *
  *                                                              *
  *                      D/T2817  D/T2818  E2827/K               *
  *                      SYSPLEXDS  ZOS0201C/K                   *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Data sharing applications require additional high performance
  oriented data sharing function that will conditionally suppress
  the writing of application data to a cache structure when no
  other application connectors have registered interest in a data
  item.  In the cases where data items are not required to be
  shared across multiple users, there is no need to write the data
  to the cache structure and incur the overhead of coupling
  facility storage usage and subsequent cast-out processing. The
  data can can be written directly to permanent storage without
  ever residing in the cache structure (i.e. "write-around").
  
  When a cache request is made that requests registration of
  interest in a cache structure data item, the system and coupling
  facility need to test local cache controls representing the
  connector prior to registering interest in a data item.
  the system needs to perform diagnostic data collection and z/OS
  must ensure that the affected connector is terminated/detached.
  
  When a structure is deallocated, the system must wait
  until it observes an increase in free coupling
  facility storage before issuing an ENF 35 signal for
  general coupling facility resource availability.
  

Problem conclusion

• KEYWORDS: ZOS0202C/K ZOS0203C/K
  

Temporary fix

Comments

• This APAR provides the z/OS support for exploiting new CFCC
  function for coupling facility (CF) structures residing in CFs
  defined on an IBM zEnterprise EC12 (zEC12) processor
  at CFLEVEL 18 and select levels of CFs defined on
  IBM zEnterprise 114 (z114) and IBM zEnterprise 196 (z196)
  processors.  The following new function is available to z/OS R12
  and z/OS R13 users of coupling facility structures residing in
  coupling facilities at the requisite microcode load (MCL) level:
  
  Users of the IXLCACHE macro that write application data to cache
  structures may request that write operations be suppressed to
  reduce cache structure overload and cast-out processing
  requirements when specific conditions for the data item to
  written are met. See the IXLCACHE macro keyword LOCALREGCNTL
  in z/OS MVS Programming: Sysplex Services Guide and
  z/OS MVS Programming: Sysplex Services Reference for
  more information on the usage of the write suppression function.
  
  Connector local cache controls verification will implicitly
  be performed by the system when registration of interest in a
  data item is requested on the following IXLCACHE request types:
  
     o READ_DATA,
     o WRITE_DATA,
     o CASTOUT_DATA,
     o WRITE_DATALIST,
     o REG_NAMELIST
  
  In the event of a verification failure, the system will invoke
  connector termination processing based on the TERMLEVEL
  specified on the IXLCONN macro. An ABENDS026 (ABEND026)
  RSN0C0E1052 will be issued to terminate the connector's owning
  task and collect diagnostic information.
  
  Freeing of coupling facility structure space will be performed
  in the background. ENF35 for general coupling facility resource
  availability will be issued when structure space has been freed
  by the coupling facility and the system observes a change in
  coupling facility free space.
  
  
  The functionality and coexistence support provided by the APAR
  is not effective on a given system unless coupling facility
  structures accessed by the system reside on a coupling facility
  with support for write suppression, local cache controls
  validation and background extended structure dump and deallocate
  processing. The applicable Coupling Facility Control Code
  microcode loads (MCLs) that contain the aforementioned support
  are:
  
  z114 (2818)
  DR93G CFCC EC N48162 MCL012 CFCC Release 17 Service Level 10.15
  
  z196 (2817)
  DR93G CFCC EC N48162 MCL012 CFCC Release 17 Service Level 10.15
  
  zEC12 (2827)
  CFCC Release 18
  
  There is no direct installation dependency between this APAR and
  the CFCC support - either can be installed without the presence
  of the other. However, both must be present in order for write
  suppression, local cache controls validation and background
  structure dump and deallocation processing to be effective.
  
  
  PUBLICATION UPDATES
  
  Documentation updates for this APAR are located in a
  pdf file, OA37550.pdf, available at:
  
  
  http://publibz.boulder.ibm.com/zoslib/pdf/OA37550.pdf
  
  Summary of Publication Updates:
  
  +--- PUBLICATION AFFECTED --------------------------------+
  |                                                         |
  | o   z/OS MVS Programming: Sysplex Services Guide -      |
  |     SA22-7617-xx                                        |
  |                                                         |
  +---------------------------------------------------------+
  
  - Information on the usage of parameter LOCALREGCNTL
    to request conditional writing of data based on
    local cache registration for IXLCACHE WRITE_DATA and
    WRITE_DATALIST operations.
  
  +--- PUBLICATION AFFECTED --------------------------------+
  |                                                         |
  | o   z/OS MVS Programming: Sysplex Services Reference -  |
  |     SA22-7618-xx                                        |
  |                                                         |
  +---------------------------------------------------------+
  
  - Detailed description of new parameter LOCALREGCNTL
    for IXLCACHE WRITE_DATA and WRITE_DATALIST operations.
  
  - Syntax diagram updates for the usage of LOCALREGCNTL
    for IXLCACHE WRITE_DATA and WRITE_DATALIST operations.
  
  - New reason codes introduced for conditional write
    operation requests to a cache structure.
  
  +--- PUBLICATION AFFECTED --------------------------------+
  |                                                         |
  | o   z/OS MVS Data Area Volume 4 -                       |
  |     GA32-0856-xx                                        |
  |                                                         |
  +---------------------------------------------------------+
  
  - Update to IXCYQUAA QUREQFEATURES structure which provides a
    new field that indicates whether support for write
    suppression based on local cache registration is supported on
    the system.
  
  - Updates to IXLYAMDA include new storage class
    counters associated with conditional writes.
  
  - Update to IXLYCAA to include a new write suppression
    vector (CAAWRITESUPPRESSVECTOR) returned on an IXLCACHE
    WRITE_DATALIST operation.
  
  - Updates to IXLYCON are for new reason code constants
    for reason codes returned on IXLCACHE
    WRITE_DATA and WRITE_DATALIST operations that are
    associated with conditional write requests.
  
  - Updates to IXLYCSCS include new storage class
    counters returned on an IXLCACHE READ_STGSTATS operation.
  
  - Updates to IXLYDSCC include new storage class
    counters associated with conditional writes.
  
  All of the updates included in this APAR will appear
  in a future refresh of the affected publications.
  
  E2827/K
  
  MODULES AFFECTED:
  
  IXLA1MG
  IXLF1STC
  IXLF1TF4
  IXLM1MS2
  IXLM2DRR
  IXLM2DSP
  IXLM2XRQ
  IXLR1CAC
  IXLR1CRR
  IXLR1DIA
  IXCF1SRM
  IXCI2PH1
  IXCL2RHT
  IXCL2SCC
  IXCL2TSK
  IXCM2MS2
  ×**** PE13/11/08 FIX IN ERROR. SEE APAR OA38312  FOR DESCRIPTION
  

APAR Information

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

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

  UA66416 UA66417 UA66418 UA66419

Modules/Macros

• IXCF1SRM IXCI2PH1 IXCL2RHT IXCL2SCC IXCL2TSK
  IXCM2MS2 IXCYQUAA IXLA1MG  IXLCACHE IXLF1STC IXLF1TF4 IXLM1MS2
  IXLM2DRR IXLM2DSP IXLM2XRQ IXLR1CAC IXLR1CRR IXLR1DIA IXLYAMDA
  IXLYCAA  IXLYCON  IXLYCSCS IXLYDSCC
  

Fix information

• Fixed component name

  CROSS SYS.EXT.S

• Fixed component ID

  5752SCIXL

Applicable component levels

• R760 PSY UA66417

     UP12/09/12 P F209

• R770 PSY UA66418

     UP12/09/12 P F209

• R780 PSY UA66419

     UP12/09/12 P F209

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.