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Date: Thu, 10 Jan 2002 18:47:45 -0800 (PST)
From: Nigel Gamble <nigel@nrg.org>
Reply-To: nigel@nrg.org
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
cc: Rob Landley <landley@trommello.org>, Andrew Morton <akpm@zip.com.au>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [2.4.17/18pre] VM and swap - it's really unusable
In-Reply-To: <E16OkSV-0005EZ-00@the-village.bc.nu>
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On Thu, 10 Jan 2002, Alan Cox wrote:
> The fun below 1mS comes from
>
> 	1.	APM bios calls where the bios decides to take >1mS to have
> 		a chat with your batteries
> 	2.	Video cards pulling borderline legal PCI tricks to get
> 		better benchmarketing by stalling the entire bus

Don't forget the embedded space, where the hardware vendor can ensure
that their hardware is well-behaved.  Even on a PC, it is possible for
someone who cares about realtime to spec a reasonable system.

On good hardware, we can easily do much better than 1ms latency with a
preemptible kernel and a spinlock cleanup.  I don't think the
limitations of some PC hardware should limit our goals for Linux.

Nigel Gamble                                    nigel@nrg.org
Mountain View, CA, USA.                         http://www.nrg.org/

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