PM70517: EBA PMI STATISTICS HAVE A SIGNIFICANT IMPACT ON PERFORMANCE

8.5.0.2: WebSphere Application Server V8.5 Fix Pack 2
8.0.0.6: WebSphere Application Server V8.0 Fix Pack 6
8.0.0.7: WebSphere Application Server V8.0 Fix Pack 7
8.0.0.8: WebSphere Application Server V8.0 Fix Pack 8
8.0.0.9: WebSphere Application Server V8.0 Fix Pack 9
8.0.0.10: WebSphere Application Server V8.0 Fix Pack 10
8.0.0.11: WebSphere Application Server V8.0 Fix Pack 11
8.0.0.12: WebSphere Application Server V8.0 Fix Pack 12
8.0.0.13: WebSphere Application Server V8.0 Fix Pack 13
8.0.0.14: WebSphere Application Server V8.0 Fix Pack 14
8.0.0.15: WebSphere Application Server V8.0 Fix Pack 15

APAR status

• Closed as program error.

Error description

• When PMI is enabled and any OSGI applications are used,
  including Blueprint applications, there is a significant
  performance degradation proportional to the size of the OSGI
  applications.
  

Local fix

• Local Fix￘
  None
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server OSGI applications                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: Enabling PMI has an excessive           *
  *                      performance impact when OSGI            *
  *                      applications are used.                  *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  OSGI applications PMI counters used the PMI framework's cache
  to store objects required to increment each counter.  This
  cache is based on a synchronized Collection and consequently
  excessive lock contention causes increased CPU utilization and
  performance degradation.
  

Problem conclusion

• This APAR resolves the problem by introducing a cache
  specifically for OSGI applications.  This cache is based on
  java.util.ConcurrentHashMap and so has significantly reduced
  contention compared to the previous cache.
  
  This APAR also introduces a custom property.
  
  com.ibm.ws.eba.pmi.enabled (default value is 'true')
  
  This property can be set on the JVM as a system property and
  controls whether any OSGI applications PMI counters (including
  Blueprint) are ever created.  Setting this property to
  anything other than 'true' will disable OSGI applications PMI
  counters and therefore eliminate any overhead incurred by
  OSGI applications PMI counters when PMI statistics are enabled.
  
  The fix for this APAR is currently targeted for inclusion in
  fix pack 8.0.0.6 and 8.5.0.2.  Please refer to the Recommended
  Updates page for delivery information:
  
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

Temporary fix

Comments

APAR Information

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

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

Fix information

• Fixed component name

  WEBS APP SERV N

• Fixed component ID

  5724H8800

Applicable component levels

• R800 PSY

     UP

• R850 PSY

     UP