IV78828: HIGH CPU USAGE CAUSED BY EXCESSIVE JIT COMPILATION FAILURES

APAR status

• Closed as program error.

Error description

• Error Message: The symptom is sustained high CPU usage after
  start-up of one or more JIT compilation threads. The error
  message "compilationCodeReservationFailure" can be found in the
  JIT compiler verbose log, collected using the option
  -Xjit:verbose,vlog=/path/for/logfile.log
  .
  Stack Trace: N/A
  .
  This problem can only occur if the Java Runtime Environment is
  using a shared class cache with AOT compilation enabled.
  

Local fix

• This problem can be worked around by disabling AOT compilation
  with the Java option -Xnoaot
  

Problem summary

• The JIT compiler uses multiple code caches to store the JIT
  compiled machine instructions. To avoid synchronization issues
  among multiple compilation threads, the JIT compiler has a
  mechanism in which a code cache can temporarily be reserved by a
  compilation thread. In some rare instances when a code cache is
  reserved for the purpose of an AOT load operation, the code
  cache can wrongly remain reserved indefinitely, preventing any
  compilation thread from using it. This can result in many
  compilation failures with the described error message.
  

Problem conclusion

• The JIT compiler has been updated to prevent code caches from
  being reserved indefinitely in these cases.
  .
  This APAR will be fixed in the following Java Releases:
     7    SR9 FP30  (7.0.9.30)
     8    SR2 FP10  (8.0.2.10)
     6 R1 SR8 FP20  (6.1.8.20)
     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:

  PI52577

Fix information

• Fixed component name

  JIT

• Fixed component ID

  620700124

Applicable component levels

• R260 PSY

     UP

• R130 PSY

     UP