IJ12948: JAVA JIT: HANG IN TR_PARAMETERTOARGUMENTMAPPER::LOOKFORMODIFIEDPARAMETERS(TR::NODE*)

APAR status

• Closed as program error.

Error description

• Error Message: A hang in the JVM.
  .
  Stack Trace:
  TR_ParameterToArgumentMapper::lookForModifiedParameters(TR::Node
  *) () from libj9jit29.so
  TR_ParameterToArgumentMapper::lookForModifiedParameters() ()
  from libj9jit29.so
  TR_ParameterToArgumentMapper::initialize(TR_CallStack*) () from
  libj9jit29.so
  TR_InlinerBase::inlineCallTarget2(...) () from libj9jit29.so
  TR_InlinerBase::inlineCallTarget(...) () from libj9jit29.so
  TR_MultipleCallTargetInliner::inlineCallTargets(...) () from
  libj9jit29.so
  ...
  With the top frame <lookForModifiedParameters(TR::Node*)>
  repeated several times.
  .
  The symptoms can be reported as Hang, slow performance or
  high-CPU. The real issues is a very long compile by in one of
  the JIT compiler threads but since there are several compiler
  threads it's possible for the customer to report only unexpected
  slow response times or just unusually high CPU consumption.
  

Local fix

• The problem can be avoided by globally disabling inlining but
  this may result in an unacceptable performance degradation.
  -Xjit:disableInlining
  The problem can be avoided with a minor performance impact by
  disabling inlining on a single method, but you would need to
  discover which method is hung in order to do that.
  -Xjit:{Package/Class.Method*}{disableInlining)
  

Problem summary

• The JIT was using a recursive method to analyse parameters
  during inlining, but there is a possibility that the parameters
  may appear several times during the analyse leading to extremely
  long compile times.
  

Problem conclusion

• The JIT was modified to remove the recursion and avoid repeated
  analysis of the same parameters.
  .
  This APAR will be fixed in the following Java Releases:
     8    SR5 FP30  (8.0.5.30)
  .
  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