0 Replies Latest reply: Jun 22, 2009 1:37 PM by 843829 RSS

    spikes in old gen usage when using CMS collector

    843829
      Hi,

      The following is JSTAT output -

      315.1 135296.0 135115.0 1572864.0 247205.3 20 0 0.000 4.562
      315.3 135296.0 135115.0 1572864.0 *1561428.0* 21 0 0.000 4.562
      315.6 135296.0 135115.2 1572864.0 270572.4 21 0 0.000 4.762

      (some) JMV options used: -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:ParallelGCThreads=4 -XX:SurvivorRatio=8 -XX:TargetSurvivorRatio=90

      JVM: 1.6.0

      How do I explain those spikes? Are they normal? Instantaneous jump & fall. Further doesn't look like a FGC happened, which is making it all the more curious!