Re: Regression seen for patch "sched:dont decrease idle sleep avg"

From: Mike Galbraith
Date: Wed May 17 2006 - 05:48:20 EST


On Wed, 2006-05-17 at 18:23 +1000, Con Kolivas wrote:

> There is a ceiling to the priority beyond which tasks that only ever sleep
> for very long periods cannot surpass.

(Hmm. The intent is more clear, ie reserve the top for low latency
tasks,... but that sounds a bit like xmms protection.)

The main problem I see with this ceiling, solely from the interactivity
viewpoint, is that interactive tasks which have started burning cpu
and/or freshly forked interactive tasks land in the same spot. Thud.c
demonstrates this problem quite well. You don't want a few copies of
thud in the same queue with your interactive task, much less above it if
it's used enough cpu to drop a notch or two. Much pain ensues.

-Mike

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