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From: Alexander Clouter <alex@digriz.org.uk>
To: linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC] x86: fix confusing name of /proc/cpuinfo "ht" flag
Date: Thu, 12 Nov 2009 17:07:32 +0000	[thread overview]
Message-ID: <kvrts6-7b4.ln1@chipmunk.wormnet.eu> (raw)
In-Reply-To: 4AFB2298.5040903@nortel.com

Chris Friesen <cfriesen@nortel.com> wrote:
>> 
>> "ht" flag indicates only ability to detect siblings not HT presence itself.
>> 
>> Inspired by:
>> http://www.codemonkey.org.uk/2009/11/10/common-hyperthreading-misconception/
>> 
>> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
>> ---
>> It could be that there are some user-space programs depending on "ht"
>> flag so the patch is marked as RFC..
> 
> If a cpu is capable of ht but doesn't have any siblings, do we actually
> care?
> 
I have a Core2 Duo U7600 with siblings set to 2 and the 'ht' flag and I 
know the CPU in my lapdog does not actually support hyperthreading.

> If many people consider the "ht" flag to indicate that hyperthreading is
> actually available, what about instead changing the meaning of the "ht"
> flag to indicate that there actually are siblings?
> 
Could be determined surely by "grep siblings /proc/cpuinfo"?

Cheers

-- 
Alexander Clouter
.sigmonster says: Old musicians never die, they just decompose.


  reply	other threads:[~2009-11-12 17:08 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-11 20:34 [PATCH RFC] x86: fix confusing name of /proc/cpuinfo "ht" flag Bartlomiej Zolnierkiewicz
2009-11-11 20:46 ` Chris Friesen
2009-11-12 17:07   ` Alexander Clouter [this message]
2009-11-11 21:35 ` Jeff Garzik
2009-11-12  6:59 ` Ingo Molnar
2009-11-12  7:08   ` H. Peter Anvin
2009-11-12  8:13     ` Ingo Molnar
2009-11-12 15:18       ` H. Peter Anvin
2009-11-12 17:59         ` Ingo Molnar
2009-11-12 18:37           ` Dave Jones
2009-11-12 19:49             ` H. Peter Anvin
2009-11-13  7:42               ` Ingo Molnar
2009-11-13 10:24                 ` Bartlomiej Zolnierkiewicz
2009-11-13  7:17           ` H. Peter Anvin

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