title: Calculate CPU usage for an application
body: <p>I need to calculate the cpu usage of a perticular process in android device. I have tried to find it out using top command.
  Problem is that it is completely different from the android assistant which is showing cpu usage in RTCPU percentange.
  I dont know what is RTCPU. Can anyone explain me ?</p>
  
  <p>I also want to know that CPU usage I have found using top command is correct or not...</p>