Subject: Re: [PATCH] mm: yield during swap prefetching
From: Lee Revell <rlrevell@joe-job.com>
To: Con Kolivas <kernel@kolivas.org>
Cc: Andrew Morton <akpm@osdl.org>, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org, ck@vds.kolivas.org
In-Reply-To: <200603081322.02306.kernel@kolivas.org>
References: <200603081013.44678.kernel@kolivas.org>
	 <200603081312.51058.kernel@kolivas.org> <1141784295.767.126.camel@mindpipe>
	 <200603081322.02306.kernel@kolivas.org>
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Date: Tue, 07 Mar 2006 21:27:13 -0500
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On Wed, 2006-03-08 at 13:22 +1100, Con Kolivas wrote:
> > How is the scheduler supposed to know to penalize a kernel compile
> > taking 100% CPU but not a game using 100% CPU?
> 
> Because being a serious desktop operating system that we are (bwahahahaha) 
> means the user should not have special privileges to run something as simple 
> as a game. Games should not need special scheduling classes. We can always 
> use 'nice' for a compile though. Real time audio is a completely different 
> world to this.  

Actually recent distros like the upcoming Ubuntu Dapper support the new
RLIMIT_NICE and RLIMIT_RTPRIO so this would Just Work without any
special privileges (well, not root anyway - you'd have to put the user
in the right group and add one line to /etc/security/limits.conf).

I think OSX also uses special scheduling classes for stuff with RT
constraints.

The only barrier I see is that games aren't specifically written to take
advantage of RT scheduling because historically it's only been available
to root.

Lee

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