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Date: Wed, 21 Aug 2002 07:48:21 -0600 (MDT)
From: James Bourne <jbourne@mtroyal.ab.ca>
To: "Reed, Timothy A" <timothy.a.reed@lmco.com>
cc: linux-kernel@vger.kernel.org
Subject: Re: Hyperthreading
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On Wed, 21 Aug 2002, Reed, Timothy A wrote:

> Anyone,
> 
> Can anyone lead me to a good source of information on what options should be
> in the kernel for hyperthreading??  I am still fighting with a
> sub-contractor over kernel options.

As long as you have a P4 and use the P4 support you will get
hyperthreading with 2.4.19 (CONFIG_MPENTIUM4=y).  2.4.18 you have to also 
turn it on with a lilo option of acpismp=force on the kernel command line.

You might want to balance IRQs across the cpus.  Ingo Molnar has created
patches for this, which I've put on my website
at http://www.hardrock.org/kernel/.

hyperthreading will give you some performance boostes, but *only*
if you have many runable processes a majority of the time, or very heavily
threaded applications running on the system.  (an example would
be running 4 setiathome clients on a dual processor system).

regards
James Bourne

> Tim 
> 
> timothy.a.reed@lmco.com

-- 
James Bourne, Supervisor Data Centre Operations
Mount Royal College, Calgary, AB, CA
www.mtroyal.ab.ca

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