linux-kernel - Re: [PATCH 1/4] [x86] Add command line option to enable/disable hyper-threading.

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Date:	Fri, 1 Dec 2006 11:13:27 -0600
From:	Mark Rustad <mrustad@...il.com>
To:	Alan <alan@...rguk.ukuu.org.uk>
Cc:	Linus Torvalds <torvalds@...l.org>,
	Arjan van de Ven <arjan@...radead.org>,
	Ben Collins <ben.collins@...ntu.com>,
	Pavel Machek <pavel@....cz>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/4] [x86] Add command line option to enable/disable hyper-threading.

On Dec 1, 2006, at 10:56 AM, Alan wrote:
>> So I think people have blown those SSL timing attacks _way_ out of
>> proportion, just because it sounds technical and cool.
>>
>> Besides, most of the time you can disable HT in the BIOS, which is  
>> better
>> anyway if you don't want it.
>
> Agreed - but the SSL thing is an irrelevance. The main reason for
> disabling HT (especially on a single core CPU) is because a lot of
> workloads run faster with HT *off*.

Yes. Another way to effectively turn it off is to set maxcpus to the  
number of physical cpus in your system. So far I have not encountered  
a system that that approach does not work on.

-- 
Mark Rustad, MRustad@....com

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