IV15424: JAVA JIT PERFORMANCE ISSUE AFTER LOADING CLASS
Closed as program error.
Error Message: Performance degradation can occur when a large number of JIT compiled methods are invalidated by loading a new class. In severe cases, the degradation can appear to cause the application to hang. System monitoring tools or profilers may reveal that a lot of CPU time is consumed by the JIT compiler run-time code. . Stack Trace: Profiling may show significant time spent in TR_RuntimeAssumption::isAssumingMethod(void*) .
This issue can be worked around with -Xjit:disableInvariantArgumentPreexistence This may degrade application performance to some extent.
The problem occurs if: 1) an application runs for a long time and compiles many methods which call a given class, 2) a second class is loaded which invalidates the previously compiled methods, usually by providing an alternative implementation of an interface. The required clean-up of meta-data associated with the invalidated methods may cause a significant pause in application processing.
This defect will be fixed in: 6.0.0 SR11 6.0.1 SR4 7.0.0 SR3 . The JIT compiler run-time code has been updated to search for and update compiled method meta data in a more efficient manner.
Reported component name
Reported component ID
Last modified date
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fixed component name
Fixed component ID
Applicable component levels