title: Calculating idlness of a process in Linux
body: <p>I have a specific process with a specific id,
  I've been looking to some posts that suggests grepping on the /proc/PID/stat and doing some calculation between the utime and the stime..
  I was wondering if there was an easier way to do that, that measures the idleness time for that specific process...</p>
  
  <p>Thanks</p>