IV82903: PERFORMANCE REGRESSION DUE TO INLINING DECISION FOR POLYMORPHIC CALLSITES

APAR status

• Closed as program error.

Error description

• Error Message: Some applications showed a 7-21%% regression
  between Java 8 SR1 and SR2.
  .
  Stack Trace: This regression is possible on all platforms (X86,
  Power, System
  z)
  .
  

Local fix

Problem summary

• The regression happens because the JIT compiler chooses not to
  inline some callee methods because the callsite is very
  polymorphic.
  

Problem conclusion

• The heuristic of the inliner in the JIT compiler has been
  changed so that it makes better decision whether to inline a
  callee method for a polymorphic callsite.
  .
  This APAR will be fixed in the following Java Releases:
     8    SR3       (8.0.3.0)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the available
  Service Refreshes and Fix Packs can be found at:
             https://www.ibm.com/developerworks/java/jdk/
  

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

  JIT

• Fixed component ID

  620700124

Applicable component levels

• R130 PSY

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