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IV47468: BPM PERFORMANCE REGRESSION AFTER JAVA UPGRADE

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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
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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