IBM Support

IV82904: PERFORMANCE REGRESSION DUE TO LOADING UNALIGNED DATA FROM COMPIL ED CODE

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APAR status

  • Closed as program error.

Error description

  • Error Message: A 50% performance regression on Power platform
    may be observed on IBM JDK between Java 7 SR9 FP30 and Java 7
    SR9 FP20.
    .
    Stack Trace: N/A
    .
    

Local fix

Problem summary

  • The performance regression is due to unaligned constant data
    being loaded from compiled code. PowerPC platform has
    performance penalty on accessing unaligned memory.
    

Problem conclusion

  • The JIT has been updated, only aligned constant data will be
    generated for future access in compiled code on PowerPC.
    .
    This APAR will be fixed in the following Java Releases:
       7    SR9 FP40  (7.0.9.40)
       6 R1 SR8 FP25  (6.1.8.25)
       8    SR3       (8.0.3.0)
    .
    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 number

    IV82904

  • Reported component name

    JIT

  • Reported component ID

    620700124

  • Reported release

    260

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-03-22

  • Closed date

    2016-03-22

  • Last modified date

    2016-03-22

  • 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

  • R130 PSY

       UP



Document information

More support for: Runtimes for Java Technology
Just In Time (JIT) Compiler

Software version: 260

Reference #: IV82904

Modified date: 22 March 2016