IV80361: OUTOFMEMORYERROR FROM JIT COMPILED CODE AT LOW OPTIMIZATION LEVE LS

APAR status

• Closed as program error.

Error description

• Error Message: Java OutOfMemoryError thrown from Java program
  that does not occur when the same program is run on the same
  machine with just the interpreter.
  .
  Stack Trace: N/A
  .
  

Local fix

• The affected method can be excluded from compilation by the JIT
  by using -Xjit:exclude={package/Class.methodName(*}.
  Alternatively a specific optimisation level can be specified for
  the problem method. Optimisation levels of warm and above will
  not have the problem, e.g.
  -Xjit:{package/Class.methodName(*}(optlevel=warm)
  

Problem summary

• In some limited circumstances the JIT optimizer may choose to
  delay object deallocation at low optimization levels (often
  deallocation is deferred to the end of the method). This is
  usually harmless, but in highly constrained scenarios this may
  lead to OutOfMemoryErrors that do not occur with the interpreter
  or higher optimization levels.
  

Problem conclusion

• A new option has been added to the JIT compiler to force all JIT
  compilations to eagerly deallocate objects.
  -Xjit:enableAggressiveLiveness
  This eager deallocation comes at the cost of reduced start-up
  and/or ramp-up performance (it may take longer for the
  application to start or for the application to reach peak
  performance with the option enabled).
  .
  This APAR will be fixed in the following Java Releases:
     6 R1 SR8 FP20  (6.1.8.20)
     7    SR9 FP30  (7.0.9.30)
     8    SR2 FP10  (8.0.2.10)
     7 R1 SR3 FP30  (7.1.3.30)
  .
  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