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Date: Tue, 04 Mar 2003 14:39:30 -0600
From: "Alan L. Cox" <alc@imimic.com>
Organization: iMimic Networking, Inc.
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To: John Baldwin <jhb@FreeBSD.org>
Cc: src-committers@FreeBSD.org, cvs-src@FreeBSD.org,
	cvs-all@FreeBSD.org
Subject: Re: cvs commit: src/sys/conf options.i386 src/sys/i386/conf 
 NOTESsrc/sys/i386/i386 mp_machdep.c
References: <200303042024.h24KOrhu053770@repoman.freebsd.org>
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John Baldwin wrote:
> 
> jhb         2003/03/04 12:24:53 PST
> 
>   FreeBSD src repository
> 
>   Modified files:
>     sys/conf             options.i386
>     sys/i386/conf        NOTES
>     sys/i386/i386        mp_machdep.c
>   Log:
>   Wrap the hyperthreading support code with the HTT kernel option.
>   Hyperthreading support is now off unless the HTT option is added.
> 
>   MFC-after:      3 days
> 
>   Revision  Changes    Path
>   1.185     +1 -0      src/sys/conf/options.i386
>   1.1078    +1 -0      src/sys/i386/conf/NOTES
>   1.204     +21 -0     src/sys/i386/i386/mp_machdep.c

How hard would it be to configure the system so that the 2nd logical CPU
on a chip did nothing but field interrupts?  Given that interrupts are
going to pollute the cache and TLB anyway, two of the detrimental
effects of hyperthreading are already "bought and paid for".

Alan

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