IV82904: PERFORMANCE REGRESSION DUE TO LOADING UNALIGNED DATA FROM COMPILED CODE

APAR status

• Closed as program error.

Error description

• Error Message: A 50% performance regression on Power platform
  may be observed on IBM JDK between Java 7 SR9 FP30 and Java 7
  SR9 FP20.
  .
  Stack Trace: N/A
  .
  

Local fix

Problem summary

• The performance regression is due to unaligned constant data
  being loaded from compiled code. PowerPC platform has
  performance penalty on accessing unaligned memory.
  

Problem conclusion

• The JIT has been updated, only aligned constant data will be
  generated for future access in compiled code on PowerPC.
  .
  This APAR will be fixed in the following Java Releases:
     7    SR9 FP40  (7.0.9.40)
     6 R1 SR8 FP25  (6.1.8.25)
     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

• R260 PSY

     UP

• R130 PSY

     UP