Re: fair group scheduler not so fair?

From: Peter Zijlstra
Date: Fri May 23 2008 - 05:41:33 EST

On Fri, 2008-05-23 at 15:12 +0530, Srivatsa Vaddagiri wrote:
> On Thu, May 22, 2008 at 01:18:33PM -0700, Li, Tong N wrote:
> > Peter,
> >
> > I didn't look at your patches, but I thought you were flattening group
> > weights down to task-level so that the scheduler only looks at per-task
> > weights.
> Wouldnt that require task weight readjustment upon every fork/exit?

If you were to do that - yes that would get you into some very serious

The route I've chosen is to basically recompute it every time I need the
weight. So every time I use a weight, I do:

\Prod_{l=1} w_l/rw_{l-1}

Not doing that will get you O(n) recomputes on all sorts of situations.

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