lkml.org 
[lkml]   [2007]   [Sep]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [announce] CFS-devel, performance improvements
From
Date
On Thu, 2007-09-13 at 19:06 +0200, Peter Zijlstra wrote:
> On Thu, 2007-09-13 at 18:50 +0200, Roman Zippel wrote:
>
> > I never claimed to understand every detail of CFS, I can _guess_ what
> > _might_ have been intended, but from that it's impossible to know for
> > certain how important they are. Let's take this patch fragment:
> >
>
> delta_fair = se->delta_fair_sleep;
>
> we slept that much
>
> > - /*
> > - * Fix up delta_fair with the effect of us running
> > - * during the whole sleep period:
> > - */
> > - if (sched_feat(SLEEPER_AVG))
> > - delta_fair = div64_likely32((u64)delta_fair * load,
> > - load + se->load.weight);
>
> if we would have ran we would not have been removed from the rq and the
> weight would have been: rq_weight + weight
>
> so compensate for us having been removed from the rq by scaling the
> delta with: rq_weight/(rq_weight + weight)
>
> > - delta_fair = calc_weighted(delta_fair, se);
>
> scale for nice levels
>

Or at least, I think that is how to read it :-)

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-09-13 19:13    [W:0.072 / U:1.720 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site