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  1. JDK
  2. JDK-8221393

ResolvedMethodTable too small for StackWalking applications

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P3
    • Resolution: Fixed
    • Affects Version/s: 13
    • Fix Version/s: 13
    • Component/s: hotspot
    • Subcomponent:
    • Resolved In Build:
      b17

      Description

      See discussion in:
      http://mail.openjdk.java.net/pipermail/zgc-dev/2019-March/000605.html

      This is output from runs from that thread:
      > service.gc.0:[24304.545s][debug][membername,table] ResolvedMethod entries counted 94768 removed 92352
      > service.gc.0:[36944.749s][debug][membername,table] ResolvedMethod entries counted 64041 removed 61616
      > service.gc.0:[36944.749s][debug][membername,table] ResolvedMethod entries counted 64041 removed 61616
      > service.gc.3:[42177.904s][debug][membername,table] ResolvedMethod entries counted 19346 removed 16930
      > service.gc.1:[47231.731s][debug][membername,table] ResolvedMethod entries counted 20110 removed 17694
      > service.gc.1:[47231.731s][debug][membername,table] ResolvedMethod entries counted 20110 removed 17694
      > service.gc.3:[52267.616s][debug][membername,table] ResolvedMethod entries counted 27426 removed 25010
      > service.gc.1:[57078.463s][debug][membername,table] ResolvedMethod entries counted 30835 removed 28419
      > service.gc.3:[61907.835s][debug][membername,table] ResolvedMethod entries counted 32403 removed 29987
      > service.gc.2:[66916.223s][debug][membername,table] ResolvedMethod entries counted 34545 removed 32129
      > service.gc.2:[71786.212s][debug][membername,table] ResolvedMethod entries counted 39112 removed 36696
      > service.gc.2:[76619.460s][debug][membername,table] ResolvedMethod entries counted 34305 removed 31889

      The ResolvedMethodTable size is fixed and too small:

      class ResolvedMethodTable : public Hashtable<ClassLoaderWeakHandle, mtClass> {
        enum Constants {
          _table_size = 1007
        };

      This will cause performance degradation for lookups.

      Time to update this to use the ConcurrentHashTable?

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              • Assignee:
                stefank Stefan Karlsson
                Reporter:
                stefank Stefan Karlsson
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                Dates

                • Created:
                  Updated:
                  Resolved: