Re: sched_clock() uses are broken

Mike Galbraith
2006-05-07T17:37:15Z

On Sun, 2006-05-07 at 13:43 +0100, Russell King wrote:
> On Sun, May 07, 2006 at 10:33:41PM +1000, Nick Piggin wrote:
> > Mike Galbraith wrote:
> > >On Wed, 2006-05-03 at 03:07 +1000, Nick Piggin wrote:
> > >
> > >>Other problem is that some people didn't RTFM and have started trying to
> > >>use it for precise accounting :(
> > >
> > >
> > >Are you talking about me perchance? I don't really care about precision
> > >_that_ much, though I certainly do want to tighten timeslice accounting.
> >
> > No, sched_clock is fine to be used in CPU scheduling choices, which are
> > heuristic anyway (although strictly speaking, even using it for timeslicing
> > within a single CPU could cause slight unfairness).
>
> Except maybe if it rolls over every 178 seconds, which is my original
> point. Maybe someone could comment on my initial patch sent 5 days
> ago?

Simply ignore the wrap... unless you have a scenario where the wrap
event itself is significant event.

-Mike