$Id$

Could schedulers do a little profiling?

* scheduler keeps a list of usecs the process function of each element was
  running
* process functions are: loop, chain, get
* scheduler keeps a sum of all times
* each gst-element has a profile_percentage field

* when going to play
  * scheduler sets sum and all usecs in the list to 0
* when handling an element
  * remember old usecs t_old
  * take time t1
  * call elements processing function
  * take time t2
  * t_new=t2-t1
  * sum+=(t_new-t_old)
  * profile_percentage=t_new/sum;
  * should the percentage be averaged?
     * profile_percentage=(profile_percentage+(t_new/sum))/2.0;

* the profile_percentage shows how much CPU time the element uses in relation
  to the whole pipeline