From: Con Kolivas <kernel@kolivas.org>
To: Mike Galbraith <efault@gmx.de>
Subject: Re: [PATCH] sched: Fix adverse effects of NFS client    =?iso-8859-1?q?on=09interactive?= response
Date: Sat, 7 Jan 2006 20:30:58 +1100
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Cc: Peter Williams <pwil3058@bigpond.net.au>,
       Helge Hafting <helgehaf@aitel.hist.no>,
       Trond Myklebust <trond.myklebust@fys.uio.no>,
       Ingo Molnar <mingo@elte.hu>,
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On Saturday 07 January 2006 16:27, Mike Galbraith wrote:
> >   Personally, I think that all TASK_UNINTERRUPTIBLE sleeps should be
> > treated as non interactive rather than just be heavily discounted (and
> > that TASK_NONINTERACTIVE shouldn't be needed in conjunction with it) BUT
> > I may be wrong especially w.r.t. media streamers such as audio and video
> > players and the mechanisms they use to do sleeps between cpu bursts.
>
> Try it, you won't like it.  When I first examined sleep_avg woes, my
> reaction was to nuke uninterruptible sleep too... boy did that ever _suck_
> :)

Glad you've seen why I put the uninterruptible sleep logic in there. In 
essence this is why the NFS client interactive case is not as nice - the NFS 
code doesn't do "work on behalf of" a cpu hog with the TASK_UNINTERRUPTIBLE 
state. The uninterruptible sleep detection logic made a massive difference to 
interactivity when cpu bound tasks do disk I/O.

Cheers,
Con
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