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  1. JDK
  2. JDK-6749430

Java app (in Solaris default ptocessor set) allocates incorrect number processors to parallelGC

    Details

    • Type: Bug
    • Status: Closed
    • Priority: P2
    • Resolution: Duplicate
    • Affects Version/s: 6u4
    • Fix Version/s: None
    • Component/s: hotspot
    • Labels:
      None
    • Subcomponent:
    • CPU:
      generic
    • OS:
      solaris_10

      Description

      Customer has 16 processor Solaris server configured with as follows:
      - Processor set 1: 11 processors
      - Default processor set: 5 processors

      A java application was started in the deafult processor set. The following command was executed to list number of processors allocated to parallelGC.
      $ jinfo -flag ParallelGCThreads 10993 (where 10993 was the pid)
      jinfo response: -XX:ParallelGCThreads=13

      This indicates all 16 procesors were used to calculate the default number of processors to allocate to parallel GC. The algorithm used for this calculation is:
                (ncpus <= 8) ? ncpus : 3 + ((ncpus * 5) / 8)
      The correct answer should have been 5 processors based on a value of ncpus of 5 available in the default processor set.

      Fix requires the no of GC threads to be adjusted based on os::active_processor_count() available to the unbound Java process.

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              • Assignee:
                Unassigned
                Reporter:
                aperumai Asok Perumainar (Inactive)
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