Topic
IC4NOTICE: developerWorks Community will be offline May 29-30, 2015 while we upgrade to the latest version of IBM Connections. For more information, read our upgrade FAQ.
7 replies Latest Post - ‏2013-02-13T09:42:13Z by SystemAdmin
SystemAdmin
SystemAdmin
37422 Posts
ACCEPTED ANSWER

Pinned topic waiting and blocked threads in javacore

‏2013-02-12T17:24:18Z |
Hi,

I can see a large number of threads waiting and blocked in javacore and for each thread I can see following stack trace

at java/lang/Object.wait(Native Method)
at java/lang/Object.wait(Object.java:196(Compiled Code))
at com/ibm/ws/util/BoundedBuffer.waitGet_(BoundedBuffer.java:179(Compiled Code))
at com/ibm/ws/util/BoundedBuffer.take(BoundedBuffer.java:523(Compiled Code))
at com/ibm/ws/util/ThreadPool.getTask(ThreadPool.java:872(Compiled Code))
at com/ibm/ws/util/ThreadPool$Worker.run(ThreadPool.java:1611(Compile code))

Does any one have any idea about these stack trace? I am using Thread and Monitor Dump Analyzer for Java.

Please advise!
Thanks,

Kashif
Updated on 2013-02-13T09:42:13Z at 2013-02-13T09:42:13Z by SystemAdmin
  • bpaskin
    bpaskin
    3894 Posts
    ACCEPTED ANSWER

    Re: waiting and blocked threads in javacore

    ‏2013-02-12T17:33:15Z  in response to SystemAdmin
    Waiting for work for the web containers. These are normal and you can change the number in the web container thread pool.

    Brian
    • SystemAdmin
      SystemAdmin
      37422 Posts
      ACCEPTED ANSWER

      Re: waiting and blocked threads in javacore

      ‏2013-02-12T17:40:19Z  in response to bpaskin
      Thank you Brian for the quick reply! Waiting threads are fine but how about blocked threads? I have improved the response time of the site by increasing webcontainer thread pool, JDBC connection pool and PreParedstament cache as I was able to see saturation in these areas but the response time still needs to be reduced.

      you have mentioned to change the webcontainer thread pool, do you want me to increase it more?

      Regards,

      Kashif
      • bpaskin
        bpaskin
        3894 Posts
        ACCEPTED ANSWER

        Re: waiting and blocked threads in javacore

        ‏2013-02-12T18:06:04Z  in response to SystemAdmin
        Hi,

        You posted a stack trace, not blocked threads, so it is hard for me to understand what is going on. If increasing web container threads has helped you, I would check their usage and the time they take to complete when running your tests.

        Brian
        • SystemAdmin
          SystemAdmin
          37422 Posts
          ACCEPTED ANSWER

          Re: waiting and blocked threads in javacore

          ‏2013-02-12T19:12:01Z  in response to bpaskin
          HI Brian,

          I have also attached javacore file in my first post, If you get a chance please take a look; you will see blocked threads.

          Thanks,

          Kashif
          • bpaskin
            bpaskin
            3894 Posts
            ACCEPTED ANSWER

            Re: waiting and blocked threads in javacore

            ‏2013-02-12T20:13:08Z  in response to SystemAdmin
            To really look if there are problems you need 3 javacores that are spaced 2 mins or so apart.

            Brian
            • SystemAdmin
              SystemAdmin
              37422 Posts
              ACCEPTED ANSWER

              Re: waiting and blocked threads in javacore

              ‏2013-02-13T09:42:13Z  in response to bpaskin
              Ok then I will have to execute load test again and generate 3 javacores. Would you like to suggest any other tool to analyze javacores? If I see more than 50% thread in block condition at the peak of load does it indicates that there is some blockage?
              Kashif
      • Sunit
        Sunit
        195 Posts
        ACCEPTED ANSWER

        Re: waiting and blocked threads in javacore

        ‏2013-02-12T18:28:15Z  in response to SystemAdmin
        Use IBM WAIT tool to analyze:
        https://wait.ibm.com/

        --Sunit