1 Reply Latest reply on Sep 27, 2018 1:40 PM by Hirt-Oracle

    CPU usage graph

    Maitee

      Reg. Oracle JAVA Mission Control 6.0, there are three different contributors to overall CPU usage displayed:

      - Machines Total

      - JVM + Application

      - JVM + Application (Kernel)

       

      Is 'JVM + Application' what we know as User Space processes (assuming the other as the Kernel Space)?

      What contributes to the Machine's Total, if not the applications and the JVM's Kernel or User Space processes? Don't think, processes from the application's environment - but maybe I'm wrong.

       

      Explanations or a reference to explanations are very much appreciated, as searching public files (guides, help) and now the java forum has not been successful.

        • 1. Re: CPU usage graph
          Hirt-Oracle

          Hi there,

           

          The implementation is a bit different between the platforms. For Linux it is based on proc stat. Simplified, most of the implementations are calculating the ticks for things that are either kernel related (irq, system) or user related (user ticks) divided by all the possible ticks (including idle). Either for the JVM process alone, or all processes. The three values exposed in JFR are either the used ticks for all processes (i.e. not idle) / all possible ticks [this is the machineTotal attribute in the JFR CPULoad event], the kernel/system related ticks for the JVM process(es) / all possible ticks [jvmSystem attribute in the JFR CPULoad event], and the user related ticks for the JVM process(es) / all possible ticks [jvmUser attribute in the JFR CPU Load event].

           

          In the new visualization for JMC 7, we typically add up the user and system loads for the JVM process to a single value in the overview page, and show all three separately in the Processes page.