From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Nicholas Berry <nikberry@med.umich.edu>
Cc: grendel@caudium.net, willy@w.ods.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Very high load on P4 machines with 2.4.28
Date: Wed, 05 Jan 2005 00:02:08 +0000 [thread overview]
Message-ID: <1104879448.17176.72.camel@localhost.localdomain> (raw)
In-Reply-To: <s1dad55b.011@med-gwia-02a.med.umich.edu>
On Maw, 2005-01-04 at 22:41, Nicholas Berry wrote:
> Indeed. AIX (sorry) 5.3 on POWER5 explicitly disables SMT (IBM
> hyperthreading) if the load doesn't warrant it.
>
> (Now how about that for Linux?) :)
It would be very nice to do but AFAIK no current processor with
hypedthreading lets you do dynamic disabling. We do try and land tasks
on the real processors before other SMT threads and to leave the other
threads idle. I'm not sure we could do much more unless flipping the
cache control bits on packages when idle is a win (which I doubt)
next prev parent reply other threads:[~2005-01-05 1:09 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-04 22:41 Very high load on P4 machines with 2.4.28 Nicholas Berry
2005-01-04 23:05 ` Jesper Juhl
2005-01-05 0:02 ` Alan Cox [this message]
2005-01-05 1:21 ` Con Kolivas
2005-01-05 7:12 ` Anton Blanchard
-- strict thread matches above, loose matches on Subject: below --
2005-01-05 11:09 Indrek Kruusa
2005-01-05 14:03 ` Alan Cox
2005-01-04 19:58 Marek Habersack
2005-01-04 19:56 Marek Habersack
2005-01-04 22:03 ` Willy Tarreau
2005-01-04 23:07 ` Marek Habersack
2005-01-05 5:28 ` Willy Tarreau
2005-01-05 11:32 ` Marek Habersack
2005-01-04 22:05 ` Willy Tarreau
2005-01-04 23:09 ` Marek Habersack
2005-01-05 9:42 ` Marcelo Tosatti
2005-01-05 17:49 ` Marek Habersack
2005-01-06 18:56 ` Denis Vlasenko
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