IV18275: LOWER PERFORMANCE DUE TO FAILED COMPILATIONS

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APAR status

  • Closed as program error.

Error description

  • Error Message: N/A
    .
    Stack Trace: N/A
    .
    Failed compilations can be tracked with a verbose log:
    java -Xjit:verbose,vlog=vlog.txt
    Note that a compilation can be retried up to 3 times before JIT
    giving up. The important case to consider are:
    1) Methods continue as interpreted
    2) Methods remain in 'profiling' mode
    

Local fix

  • Depending on the type of failure the following options could
    avoid the problem:
    -Xjit:{method}(disableProfiling)
    -Xjit:{method}(optLevel=cold)  (or any other suitable
    optimization level)
    

Problem summary

  • In some cases the JIT may fail compilations repeatedly such that
    the methods in question remain interpreted or in 'profile
    collection' mode. This can affect the performance of the JVM to
    a varying degree depending on how often the affected methods are
    invoked.
    

Problem conclusion

  • This defect will be fixed in:
    6.0.1 SR2
    7.0.0 SR1
    .
    Two of conditions leading to compilation failures have been
    addressed such that methods will not be be stuck in profiling or
    interpreted code.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV18275

  • Reported component name

    JIT

  • Reported component ID

    620700124

  • Reported release

    260

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-03-26

  • Closed date

    2012-03-26

  • Last modified date

    2012-06-01

  • 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


More support for:

Runtimes for Java Technology
Just In Time (JIT) Compiler

Software version:

260

Reference #:

IV18275

Modified date:

2012-06-01

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