APAR status
Closed as program error.
Error description
Error Message: N/A . Stack Trace: N/A . A 7% regression is measured on a standard set of performance tests for BPM, based on WAS 8.5.0.1. The performance regression occurs after upgrading from Java 6.0.1 SR1 to Java 6.0.1 SR3. The regression is consistent between runs and is validated through at least 5 different measurement sets.
Local fix
Problem summary
The problem was caused by a change in the JIT profiler. The profiler had been extended in SR3 to profile more speculative code paths through a method, but a new correctness check was missing one very important condition, and hence acting very conservatively, effectively disabling profiling in many cases.
Problem conclusion
This defect will be fixed in: 6.0.1 SR7 7.0.0 SR6 . The problematic change had already been reverted earlier, but the fix was incorrectly grouped with other aggressive optimizations which would only be available if -Xaggressive was enabled. This APAR enables the fix for all cases, essentially restoring the behaviour of the Java 6.0.1 SR1 JIT profiler.
Temporary fix
Comments
APAR Information
APAR number
IV47468
Reported component name
JIT
Reported component ID
620700124
Reported release
260
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2013-08-23
Closed date
2013-08-26
Last modified date
2013-08-26
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
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Document Information
Modified date:
26 August 2013