From: Con Kolivas <kernel@kolivas.org>
To: Nicholas Berry <nikberry@med.umich.edu>
Cc: grendel@caudium.net, willy@w.ods.org, linux-kernel@vger.kernel.org
Subject: Re: Very high load on P4 machines with 2.4.28
Date: Wed, 05 Jan 2005 12:21:53 +1100 [thread overview]
Message-ID: <41DB4131.2020400@kolivas.org> (raw)
In-Reply-To: <s1dad55b.011@med-gwia-02a.med.umich.edu>
Nicholas Berry wrote:
>>>>Willy Tarreau <willy@w.ods.org> 01/04/05 5:05 PM >>>
>>>
>>>Oh, while I'm at it, are you using hyperthreading, and if so, could
>
> you
>
>>>disable it ? I have seen many cases where it degrades performances
>>>significantly (eg: highly loaded user space network applications).
>
>
> 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?) :)
Didn't he say that it degrades performance under load? You're asking to
disable it under low load. The 2.6 scheduler is already supposed to try
and move tasks to full cores if they're empty instead of smt siblings.
Con
next prev parent reply other threads:[~2005-01-05 1:23 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
2005-01-05 1:21 ` Con Kolivas [this message]
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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