From: Andi Kleen <ak@suse.de>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Why HZ on i386 is 100 ?
Date: 23 Apr 2002 09:17:25 +0200 [thread overview]
Message-ID: <p73g01m994q.fsf@oldwotan.suse.de> (raw)
In-Reply-To: <3CC4861C.F21859A6@mvista.com.suse.lists.linux.kernel> <E16zuPf-0007yD-00@the-village.bc.nu.suse.lists.linux.kernel>
Alan Cox <alan@lxorguk.ukuu.org.uk> writes:
> > The problem is in accounting (or time slicing if you prefer) where we
> > need to start a timer each time a task is context switched to, and stop
> > it when the task is switched away. The overhead is purely in the set up
> > and tear down. MOST of these never expire.
>
> Done properly on many platforms a variable tick is very very easy and also
> very efficient to handle. X86 is a paticular problem case because the timer
> is so expensive to fiddle with
Depends. On modern x86 you can either use the local APIC timer or
the mmtimers (ftp://download.intel.com/ial/home/sp/mmts097.pdf -
should be in newer x86 chipsets). Both should be better than the
8254 timer and are also not expensive to work with.
-Andi
next parent reply other threads:[~2002-04-23 7:17 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <3CC4861C.F21859A6@mvista.com.suse.lists.linux.kernel>
[not found] ` <E16zuPf-0007yD-00@the-village.bc.nu.suse.lists.linux.kernel>
2002-04-23 7:17 ` Andi Kleen [this message]
2002-04-23 19:09 ` Why HZ on i386 is 100 ? george anzinger
2002-04-24 1:42 ` Alan Cox
2002-04-24 20:20 ` george anzinger
2002-04-27 20:26 ` Alan Cox
2002-04-28 6:02 ` george anzinger
2002-04-28 9:12 ` Alan Cox
2002-04-28 17:34 ` george anzinger
2002-04-28 18:59 ` Alan Cox
2002-04-28 21:50 ` george anzinger
2002-04-29 0:14 ` Alan Cox
2002-04-23 19:24 ` george anzinger
2002-04-23 19:35 ` Andi Kleen
2002-04-24 17:25 ` Maciej W. Rozycki
2002-04-17 0:33 Chen, Kenneth W
2002-04-17 1:02 ` Davide Libenzi
-- strict thread matches above, loose matches on Subject: below --
2002-04-16 10:41 Cabaniols, Sebastien
2002-04-16 7:47 Olaf Fraczyk
2002-04-16 8:14 ` William Lee Irwin III
2002-04-16 8:18 ` BALBIR SINGH
2002-04-16 10:29 ` Liam Girdwood
2002-04-16 10:01 ` Olaf Fraczyk
2002-04-16 13:35 ` Terje Eggestad
2002-04-16 13:38 ` Mark Mielke
2002-04-16 13:55 ` Terje Eggestad
2002-04-16 15:32 ` Rik van Riel
2002-04-16 16:12 ` Chris Friesen
2002-04-16 17:12 ` Mark Mielke
2002-04-16 13:58 ` Alan Cox
2002-04-17 0:22 ` H. Peter Anvin
2002-04-16 16:27 ` Linus Torvalds
2002-04-16 16:50 ` David Mosberger
2002-04-16 17:18 ` Davide Libenzi
2002-04-16 17:52 ` David Mosberger
2002-04-16 18:10 ` Davide Libenzi
2002-04-17 0:49 ` David Mosberger
2002-04-17 0:57 ` Robert Love
2002-04-17 1:07 ` Davide Libenzi
2002-04-17 5:18 ` Mark Mielke
2002-04-17 5:34 ` Linus Torvalds
2002-04-17 6:01 ` Robert Love
2002-04-17 6:17 ` David Mosberger
2002-04-17 7:59 ` arjan
2002-04-17 8:04 ` Matti Aarnio
2002-04-23 22:42 ` Albert D. Cahalan
2002-04-17 10:12 ` Martin Dalecki
2002-04-18 1:51 ` Dan Mann
2002-04-17 1:22 ` Davide Libenzi
2002-04-17 3:19 ` Ben Greear
2002-04-17 7:55 ` Helge Hafting
2002-04-21 18:00 ` Pavel Machek
2002-04-22 17:20 ` John Alvord
2002-04-22 21:52 ` george anzinger
2002-04-22 23:06 ` J.D. Bakker
2002-04-22 23:26 ` Anton Blanchard
2002-04-23 19:03 ` george anzinger
2002-04-23 7:08 ` Alan Cox
2002-04-22 17:24 ` David Mosberger
2002-04-16 12:42 ` Richard B. Johnson
2002-04-16 12:31 ` Richard B. Johnson
2002-04-16 14:04 ` Bill Davidsen
2002-04-16 21:34 ` bert hubert
2002-04-16 22:21 ` Andreas Dilger
2002-04-16 22:37 ` Herbert Xu
2002-04-16 22:56 ` Andreas Dilger
2002-04-17 0:34 ` J. Dow
2002-04-17 2:40 ` Herbert Xu
2002-04-17 12:44 ` Kent Borg
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