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IV29708: SUN/IO/CONVERTERS IS CONSUMING 3%+ MORE CPU COMPARED TO JAVA6 AN D ALSO OBSERVED BIG LOCK CONTENTION INCREASE AT THE SAME POINT

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APAR status

  • Closed as program error.

Error description

  • Error Message: A snip from the scs profile of a run with a
    recent XS 8.6 build with the 626sr1 JVM:
      Parent      0   0.00   0.34           0          48
    J:sun/io/CharToByteConverter.getConverter(Ljava/lang/String;)Lsu
    n/io/CharToByteConverter;
    
        Self      0   0.00   0.34           0          48
    J:sun/io/Converters.newConverter(ILjava/lang/String;)Ljava/lang/
    Object;
    
       Child      0   0.00   0.34           0          48
    J:sun/io/Converters.newConverter(Ljava/lang/String;Ljava/lang/Cl
    ass;)Ljava/lang/Object;
    
    And here's a snip from an scs profile with the same XS 8.6
    build, using the Java7sr2 JVM:
      Parent      0   0.21   3.48          24         401
    J:sun/io/CharToByteConverter.getConverter(Ljava/lang/String;)Lsu
    n/io/CharToByteConverter;
    
        Self      0   0.21   3.48          24         401
    J:sun/io/Converters.newConverter(ILjava/lang/String;)Ljava/lang/
    Object;
    
       Child      0   1.48   1.89         170         218
    J:sun/io/Converters.getConverterClass(ILjava/lang/String;)Ljava/
    lang/Class;
       Child      0   1.18   1.18         136         136
    J:sun/io/Converters.cache(ILjava/lang/Object;)Ljava/lang/Class;
       Child      0   0.00   0.20           0          23
    J:sun/io/Converters.newConverter(Ljava/lang/String;Ljava/lang/Cl
    ass;)Ljava/lang/Object;
    .
    Stack Trace: N/A
    .
    

Local fix

Problem summary

  • sun/io/Converters is consuming 3%+ more cpu compared to Java6
    and also observed big lock contention increase at the same point
    

Problem conclusion

  • This defect will be fixed in:
    7.0.0 SR4
    .
    In Java6, from sun.io.Converters.newConverter(int, String)
    method we have removed the sync block and introduced the syn
    block on sun.io.Converters.cache(int type, Object encoding)
    method inorder to avoid the deadlock and hang. This change was
    done as part of CMVC94431. Ported the fix to Java7 resolves the
    issue.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV29708

  • Reported component name

    JAVA CLASS LIBS

  • Reported component ID

    620700130

  • Reported release

    700

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-10-08

  • Closed date

    2012-10-08

  • Last modified date

    2013-02-28

  • 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

    JAVA CLASS LIBS

  • Fixed component ID

    620700130

Applicable component levels

  • R700 PSY

       UP

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Document Information

Modified date:
21 February 2022