Re: [PATCH] sched: Fixadverse effects of NFS client on interactive response

From: Lee Revell
Date: Fri Dec 23 2005 - 16:58:34 EST


On Fri, 2005-12-23 at 22:23 +0100, Trond Myklebust wrote:
> On Fri, 2005-12-23 at 16:17 -0500, Lee Revell wrote:
> > On Fri, 2005-12-23 at 22:08 +0100, Trond Myklebust wrote:
> > > On Fri, 2005-12-23 at 14:07 -0500, Lee Revell wrote:
> > >
> > > > By your logic it's also broken to use cond_resched() in filesystem code.
> > >
> > > ...and your point is?
> >
> > Reductio ad absurdum. Subsystems not using cond_resched would render
> > Linux unusable for even trivial soft realtime applications like AV
> > playback and recording.
>
> It may surprise you to learn that some people don't use their computers
> for AV playback and recording. However absurd it may seem to you, those
> people are quite happy to use 2.4.x kernels without a cond_resched
> lurking in every nook and cranny.

Of course, but I think a reasonable goal for 2.6 is to maintain the
server side performance of 2.4 but also enable desktop type applications
to work well.

cond_resched is really a temporary hack to make the desktop usable until
the kernel becomes fully preemptible.

Lee

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