IV80393: 20-34% REGRESSION IN SPECJVM2008.SERIAL ON PPC

APAR status

• Closed as program error.

Error description

• Error Message: N/A
  .
  Stack Trace: N/A
  .
  The performance regressed 20-34% running micro benchmark
  SPECjvm2008.serial on PPC.
  

Local fix

Problem summary

• The regression was introduced by the fix to a faulty
  optimization which is described in APAR IV67534. After disabling
  the faulty optimization, the JIT generates some expensive
  instructions for method java.lang.ref.SoftReference.get() on
  PPC.
  

Problem conclusion

• The JIT compiler has been updated to generate more efficient
  instructions for java.lang.ref.SoftReference.get().
  .
  This APAR will be fixed in the following Java Releases:
   8 SR2 FP10 (8.0.2.10)
   7 R1 SR4 (7.1.4.0)
  .
  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:

• Fixed component name

  JIT

• Fixed component ID

  620700124

Applicable component levels

• R130 PSY

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