2 Replies Latest reply on Aug 23, 2011 3:53 AM by tung vu

    stranger memory consumption on eden space of seam app on jboss

    tung vu Newbie

      Hi,


      i'm experiencing very stranger memory usage behavior of an seam app, running on JBoss AS. Environemnt:
      - JBoss AS 5.1.0 GA
      - Seam 2.2.0GA
      - JSF 1.2
      - HotSpot JVM 64bits on windows


      The problem is, that within the eden space (heap young generation) memory is being allocated continuing without having any workload on the app, the app just stays idle. It allocate about 45MB every 10 seconds, and after 90s the eden space gets full, then the young GC comes.


      Has someone experienced this stranger behavior? I'm SURE, that there is no any workload during monitoring, just stay IDLE. I'm using yourkit to monitor the JVM Heap. Anyone has an idea?


      Thank you!

        • 1. Re: stranger memory consumption on eden space of seam app on jboss
          Jean Luc Apprentice

          Use a profiler. You'll find out exactly what those instances are. Note that the application server is never completely idle so it's normal to see some objects being created and destroyed (there are various periodic checks, pollings and so on). But 4.5MB/s is too high.


          If you don't have a profiler, download the trial version of YourKit (it's an excellent profiler, by the way). Once you connect to the server, watch the instances and use the delta function to show what objects are created. You may not even need to look at the heap to find out.


          • 2. Re: stranger memory consumption on eden space of seam app on jboss
            tung vu Newbie

            The only thing what i found (using yourkit) is the HDScanner, which runs periodically. This HDScanner scans for changed/new files/folder  which should be hot-deployed. I could not find anything else which running and allocates memory.


            Yeah, 4,5MB/s is too high, is not acceptable. But im stuck here.


            Thx you!