Re: Scheduling problems ? [ Was: Linux 2.6.26-rc1 ]

From: Ingo Molnar
Date: Tue May 06 2008 - 09:11:28 EST



* J.A. Magallón <jamagallon@xxxxxxx> wrote:

> Hi...
>
> I have installed this kernel, and it behaves a bit strange.
>
> If I launch a movie under totem, it plays nicely (no HD, just
> 512x384). If then I start deluge with some torrents downloading, the
> video begins to loose frames and jump, like loosing 1 or 2 frames per
> second. There is not much bandwidth used, just 15-20 Kb.
>
> I have tried the same copying a kernel source tree and the video plays
> fine. So can it be something network related, os network+io to disk ?
>
> No group scheduling, 1000Hz, fully preemptive kernel. If you smell
> something and need my .config I will post it.

could you try latest -git (head v2.6.26-rc1-110-ga153063 or later).

There's scheduler interactivity fixes in it: in particular the
fair-sleepers latency bug was finally tracked down and fixed via
v2.6.26-rc1-66-ga992241 ("sched: fix normalized sleeper").

In v2.6.25 we didnt find that bug in time - see v2.6.25-rc9-1-ge2df9e0
('revert "sched: fix fair sleepers"').

Ingo
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