From: Joe Van Dyk <joevandyk@...>
Date: 2005-11-11T09:45:34+09:00
Subject: Re: [SORTA OT] Getting CPU usage of a process

On 11/10/05, Kero <kero@chello.single-dot.nl> wrote:
> > I'd like to be able to get the CPU usage of a particular process.
> > What are my options for doing so from Ruby?
> >
> > I've found the libgtop ruby binding, and I could use that, but I would
> > rather not bring in another dependency.  This will run on Linux
> > systems only.
> >
> > And would I want to use the elapsed real cpu time?  Or the sum of the
> > elapsed user and system cpu time?  (and then I believe I divide that
> > by the elapsed wall clock time)
>
> man proc, look for "/proc/[number]/stat"
> It contains a set of times spent by the process and its children.
> it also contains the starttime, so this should allow you to compute "Cpu
> usage of the process".

Thanks, I'm aware of /procproc.

I want to be able to constantly keep the user updated on how much of
the cpu the application is using.

Would I take the sum of the elapsed user and system cpu time and
divide that by the elapsed wall clock time to get the current cpu
percentage?