[collectd] cpu usage

[Massimo Canonico]

Hi,
I'm new on collectd and I'm sure that this question was already aswred 
but I do not find where.

I have a quad-core machine and I would like to know the cpu usage. 
Looking at the graph here:
http://collectd.org/wiki/index.php/Plugin:CPU

I should be able to convert the jiffies into %, but I'm not sure how.

Maybe is there a plug-in able to do that?

Right now I was trying to look into idle file in order to compute 
something like utilization = 1 - idleTime, but the file contains the 
number of jitters and I do not know how can I manage it.

Could you point me out where I can find the procedure?

Thanks,
  M