Re: yield

From: Ingo Molnar
Date: Wed Oct 03 2007 - 07:57:20 EST



* Jarek Poplawski <jarkao2@xxxxx> wrote:

> On Wed, Oct 03, 2007 at 12:55:34PM +0200, Dmitry Adamushko wrote:
> ...
> > just a quick patch, not tested and I've not evaluated all possible
> > implications yet.
> > But someone might give it a try with his/(her -- are even more
> > welcomed :-) favourite sched_yield() load.
>
> Of course, after some evaluation by yourself and Ingo the most
> interesting should be Martin's Michlmayr testing, so I hope you'll Cc
> him too?!

My current take on this: queue the current task right to the next
position in the tree (this is what this patch achieves in essence) was
one of the yield implementations we already tried in CFS but it didnt
meet the expectations of some apps. So i can only repeat my argument:
this is not something that can be "solved" in the way you imagine and
your arguments just reiterate the path that CFS has already taken in the
past. So please do not expect _us_ to go out and pester people. If
people feel so inclined, they are of course welcome to test out various
approaches. (they might as well try the original yield-granularity patch
which also makes the amount of "delay" tunable, so the ideal amount of
delay can be figured out. And of course they should also try the
existing yield flag.)

Ingo
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