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  1. JDK
  2. JDK-8259809

Remove PerfEvent class loading locking counters

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    • Enhancement
    • Resolution: Fixed
    • P4
    • 17
    • 17
    • hotspot
    • b07

    Description

      There were 4 counters added to measure the impact of locking on loading classes. The first is rarely non-zero. Are there tools that use these counters? As SUN_CLS counters, they are internal counters and there's no expectation of support.
      From: perfData.hpp

       * sun.* - unstable, unsupported interface

      // The following performance counters are added for measuring the impact
      // of the bug fix of 6365597. They are mainly focused on finding out
      // the behavior of system & user-defined classloader lock, whether
      // ClassLoader.loadClass/findClass is being called synchronized or not.
      NEWPERFEVENTCOUNTER(_sync_systemLoaderLockContentionRate, SUN_CLS, "systemLoaderLockContentionRate");
      NEWPERFEVENTCOUNTER(_sync_nonSystemLoaderLockContentionRate, SUN_CLS, "nonSystemLoaderLockContentionRate");
      NEWPERFEVENTCOUNTER(_sync_JVMFindLoadedClassLockFreeCounter, SUN_CLS, "jvmFindLoadedClassNoLockCalls");
      NEWPERFEVENTCOUNTER(_sync_JVMDefineClassLockFreeCounter, SUN_CLS, "jvmDefineClassNoLockCalls");
      NEWPERFEVENTCOUNTER(_sync_JNIDefineClassLockFreeCounter, SUN_CLS, "jniDefineClassNoLockCalls");

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              coleenp Coleen Phillimore
              coleenp Coleen Phillimore
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                Created:
                Updated:
                Resolved: