VM66090: PERFORMANCE IMPROVEMENTS FOR PCI INSTRUCTION SIMULATION

Obtain the fix for this APAR.

APAR status

• Closed as unreproducible in next release.

Error description

• PCI instruction simulation over-allocates memory which can lead
  to performance problems on systems with guest PCI device
  workloads.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of PCI Functions                   *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  ****************************************************************
  * RECOMMENDATION: APPLY PTF                                    *
  ****************************************************************
  PCI instruction simulation was overallocating a memory buffer
  which could result in poor performance for systems with a large
  amount of PCI function workloads.
  

Problem conclusion

Temporary fix

• *********
  * HIPER *
  *********
  FOR RELEASE VM/ESA CP/ESA R640 :
  PREREQ: VM65942
  CO-REQ: NONE
  IF-REQ: NONE
  

Comments

• The code of interest was updated to only allocate the
  associated pages of memory on an as-needed basis.  This ensures
  only as much memory as is actually needed is used for the
  function.
  

APAR Information

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

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

  UM35262

Modules/Macros

• HCPPCH   HCPPCK
  

Fix information

• Fixed component name

  VM CP

• Fixed component ID

  568411202

Applicable component levels

• R640 PSY UM35262

     UP17/12/20 P 1801 ¢

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.