OW26118: RAPI APPLICATION PERFORMANCE ENHANCEMENTS FOR HPDT DLCS

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• Improve RAPI receive path performance by avoiding unnecessary
  data move into IO buffers.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of RAPI applications               *
  *                 in an HPDT configuration.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: RAPI receive path has unnecessary       *
  *                      data moves into IO buffers.             *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Improve RAPI receive path performance by avoiding unnecessary
  data move into IO buffers.
  

Problem conclusion

• Logic for handling inbound RAPI session data is changed to
  keep data in CSM buffer storage whenever possible in order to
  eliminate unnecessary data moves. Data on intra-host sessions
  is carried in the most efficient type of storage based upon its
  size and execution-time constraints.
  
  Changes to modules and mappings are as follows:
  
  ISTMAPPL is changed to add a new indicator (MAP_PAGE_ELIG)
  indicating that CSM buffers obtained need not be pagefixed.
  
  ISTTSCCR is changed when building exception request to change
  XBUFLST TSCB to normal format before adding sense data to RU.
  
  ISTTSCDU is changed to handle moving data to the user area from
  TSCBs which are in XBUFLST (Extended Buffer List) format as well
  as in normal TSCB format.  XBUFLSTs may be contained in either
  TIPACs or in VTAM dataspace TSCBs.
  
  ISTTSCFO is changed to use CSM buffers for data on intra-host
  sessions when the data is larger than can be contained in 4 IO
  buffers. For intra-host sessions, CSM buffers will be requested
  page-eligible rather than fixed.
  
  ISTTSCFP is changed to handle data in XBUFLST format as well as
  normal TSCB format.  If data is in ECSA CSM buffers, or if
  persistent session recovery is pending or in progress, or if
  any CSM storage is critical or constrained, then data will be
  moved into VTAM dataspace TSCB storage. Otherwise, data in
  Dataspace CSM buffers will remain there and the XBUFLST entries
  which locate those buffers will be copied into VTAM dataspace
  storage and their original TIPAC containers will be freed.
  Any buffers in fixed CSM buffers will be marked page-eligible.
  
  ISTTSCIR is changed to allow data received in CSM buffers which
  is FM data request and whose session is not using compression,
  encryption, MACing, or segmentation to remain in CSM buffers
  instead of being copied to IO buffer storage for subsequent
  inbound processing.
  
  ISTTSCMO is changed to obtain CSM storage in page-eligible
  buffers rather than fixed buffers if MAP_PAGE_ELIG is on in
  the MAPPL parameter list.
  
  ISTTSCUD is changed to handle discarding XBUFLST-format TSCBs
  which are in VTAM dataspace TSCB storage as well as in TIPACs.
  
  ISTTSC29 is changed to handle XBUFLST-format TSCBs which are
  in VTAM dataspace TSCB storage as well as in TIPACs.
  

Temporary fix

Comments

• ×**** PE97/05/30 FIX IN ERROR. SEE APAR OW26969  FOR DESCRIPTION
  ×**** PE97/07/25 FIX IN ERROR. SEE APAR OW27440  FOR DESCRIPTION
  ×**** PE97/07/25 FIX IN ERROR. SEE APAR OW28030  FOR DESCRIPTION
  

APAR Information

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

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

  UW37917

Modules/Macros

• ISTMAPPL ISTTSCCR ISTTSCDU ISTTSCFO ISTTSCFP
  ISTTSCIR ISTTSCMO ISTTSCUD ISTTSC29 ISTTSZCT
  

Fix information

• Fixed component name

  VTAM V4 MVS/ESA

• Fixed component ID

  569511701

Applicable component levels

• R401 PSY UW37917

     UP97/05/09 P F705

Fix is available

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