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  1. JDK
  2. JDK-6646599

Classloading in 1.6.0_03-b05 server VM is much slower than 1.5 server VM

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    • Subcomponent:
    • CPU:
      x86
    • OS:
      windows_xp

      Description

      FULL PRODUCT VERSION :


      A DESCRIPTION OF THE PROBLEM :
      Startup in 1.6.0_03-b05 server VM is much slower than 1.5 server VM. It mainly looks like classloading problem. I took the numbers for my sevrer application which needs to load huge number of classes (> 10K applications classes) at startup.

      With nearly 10K classes, the times reuired to load these classes were
      1.5 client VM : 64 sec
      1.5 server VM : 27.5 sec
      1.6 client VM : 66 sec
      1.6 server VM : 53 sec

      With 15K classes, the difference became even more
      1.5 client VM : 236 sec
      1.5 server VM : 128 sec
      1.6 client VM : 274 sec
      1.6 server VM : 267 sec

      1.6 server VM performs nearly 50% slower than 1.5 server VM. In fact as you keep on increasing the number of classes to be loaded, the performance keeps on degrading.

      Seems many people have observed this :
      http://forums.java.net/jive/thread.jspa?messageID=204324
      http://forum.java.sun.com/thread.jspa?threadID=5218663

      In some cases we are seeing that complete initialization of application takes nearly 20 minutes on 1.6 server VM whereas it takes less than a minute on 1.5

      Our customers can not move to 1.6 unless this is resolved.


      REPRODUCIBILITY :
      This bug can be reproduced always.

      Release Regression From : 6
      The above release value was the last known release where this
      bug was not reproducible. Since then there has been a regression.

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              • Assignee:
                jrose John Rose
                Reporter:
                ndcosta Nelson Dcosta (Inactive)
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