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Date: Mon, 21 Jan 2002 10:15:06 -0700
From: yodaiken@fsmlabs.com
To: =?iso-8859-1?Q?Peter_W=E4chtler?= <pwaechtler@loewe-komp.de>
Cc: yodaiken@fsmlabs.com, Daniel Phillips <phillips@bonn-fries.net>,
        george anzinger <george@mvista.com>, Momchil Velikov <velco@fadata.bg>,
        Arjan van de Ven <arjan@fenrus.demon.nl>,
        Roman Zippel <zippel@linux-m68k.org>, linux-kernel@vger.kernel.org
Subject: Re: [2.4.17/18pre] VM and swap - it's really unusable
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In-Reply-To: <3C4C4C1A.9F7CE37@loewe-komp.de>; from pwaechtler@loewe-komp.de on Mon, Jan 21, 2002 at 06:12:58PM +0100
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On Mon, Jan 21, 2002 at 06:12:58PM +0100, Peter W?chtler wrote:
> > Since the preemption patch only allows additional preemption in kernel
> > mode, I'm curious to know what the compute bound tasks are doing in
> > kernel mode. Did Linux add in-kernel matrix multiplication while
> > I was not looking?
> > 
> 
> Dead right you are.
> Then there are only slow system calls left. Umh, execve(), fork()
> (with big address space) - what about page_launder etc.?

Those are, in some sense, I/O right? It's not clear to me
that preempting page_launder is sensible.

> But what is a possible explanation for the people, who think their 
> systems behave better with preemption - strong believe?

Beats me. Maybe it really does work - but maybe not and nobody
has advanced any analysis or numbers that make the case.



-- 
---------------------------------------------------------
Victor Yodaiken 
Finite State Machine Labs: The RTLinux Company.
 www.fsmlabs.com  www.rtlinux.com

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