Re: Performance graph of the Results Monitor Listener [Resolved]

[Noureddine BEKRAR <nb...@rennes.jouve.fr>]

Thank you Peter,
I followed your advice and i downloaded the Tomcat sources, and that is the results of my investigation:    

The class who play the role of status servlet is: org.apache.catalina.manager.StatusManagerServlet

The information sent to JMeter and displayed in the Monitor results listener are in the class : org.apache.catalina.manager.StatusTransformer

in the method :
 public static void writeVMState(PrintWriter writer, int mode)
        throws Exception {

        if (mode == 0){
            ....//This part of the code is not used in the case of the monitor results
        } else if (mode == 1){
            writer.write("<jvm>");
            writer.write("<memory");
            writer.write(" free='" + Runtime.getRuntime().freeMemory() + "'");
            writer.write(" total='" + Runtime.getRuntime().totalMemory() + "'");
            writer.write(" max='" + JdkCompat.getJdkCompat().getMaxMemory() + "'/>");
            writer.write("</jvm>");
        }
You can see here that the data sent by the status servlet are about the memory used by the JVM and not about the physical memory of the server.


Noureddine
  ----- Original Message ----- 
  From: Peter Lin 
  To: Noureddine BEKRAR 
  Sent: Wednesday, March 01, 2006 1:52 PM
  Subject: Re: Performance graph of the Results Monitor Listener



  the memory measurements are taken from Tomcat's status servlet, which means it is the total memory allocated by the JVM. to see, just look at tomcat's status servlet.

  hope that helps

  peter


  On 3/1/06, Noureddine BEKRAR <nb...@rennes.jouve.fr> wrote:
    Thank you Peter for your answer.

    You said :
    ...
     memory - free memory/total used
    ...

    What i want to know is which memory we speak about here : is it the total used physical memory on the server or is it the memory used by the JVM or is it the memory used by Tomcat or the memory used by the requests sent by JMeter....


    Noureddine



      ----- Original Message ----- 
      From: Peter Lin 
      To: JMeter Users List ; Noureddine BEKRAR 
      Sent: Tuesday, February 28, 2006 5:33 PM
      Subject: Re: Performance graph of the Results Monitor Listener


      Since I wrote the sampler and documentation, I'll try to explain it the best I can.

      the performance graph has 4 lines.

      health - this line is sort of arbitrary at the moment, but it basically takes the load and threads to calculate health

      load - combination of memory and threads

      memory - free memory/total used

      threads - busy/total threads


      The expected behavior of the graph is the memory usage will show a regular pattern. The red thread line should remain constant under constant load. if the red line increases rapidly, it means there's threading issues in the webapp.

      the load should show a regular pattern under constant load, since it is a combination of memory and thread stats.

      hope that helps

      peter



      On 2/28/06, Noureddine BEKRAR <nb...@rennes.jouve.fr> wrote: 
        Hi,

        Can you please tell me which memory is monitored in the "performance graph" of the "monitor results listener", is it the size of the used memory for the JVM or is it the memory used by Tomcat.
        This is the -not enough clear- explanation about this subject in the "Building Monitor testplan"

        http://jakarta.apache.org/jmeter/usermanual/build-monitor-test-plan.html :


        ... The performance graph shows for different lines. The free memory line shows how much free memory is left in the current allocated block. Tomcat 5 returns the maximum memory, but it is not graphed. In a well tuned environment, the server should never reach the maximum memory...