IV56526: HIGH CPU HANG IN JIT COMPILED METHOD

APAR status

• Closed as program error.

Error description

• Error Message: An otherwise correctly operating application
  hangs with high (single) cpu load. Analysis shows the looping
  method has been compiled by the JIT.
  .
  Stack Trace: N/A
  .
  

Local fix

• The problem can be avoided by disabling the redundant async
  check optimization with the following JIT
  option:-Xjit:disableRedundantAsyncCheckRemoval
  

Problem summary

• In certain rare circumstances the redundant async check removes
  an async check that is required for correct option. The purpose
  of the async check is to ensure that a looping java thread can
  be interrupted when necessary, for example when a global GC
  needs to be performed. The missing async check can therefore
  result in a busy hang with one thread looping while all the
  remaining threads are waiting for some global event.
  

Problem conclusion

• This APAR will be fixed in the following Java Releases:
     6    SR16      (6.0.16.0)
     7    SR7       (7.0.7.0)
     7 R1 SR1       (7.1.1.0)
  .
  The JIT has been modified to make sure that the necessary async
  checks are not removed.
  

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

• R600 PSY

     UP

• R260 PSY

     UP

• R130 PSY

     UP