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From: "H. Peter Anvin" <hpa@zytor.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Dave Jones <davej@codemonkey.org.uk>
Subject: Re: [PATCH RFC] x86: fix confusing name of /proc/cpuinfo "ht" flag
Date: Wed, 11 Nov 2009 23:08:10 -0800	[thread overview]
Message-ID: <4AFBB45A.9000606@zytor.com> (raw)
In-Reply-To: <20091112065930.GA9279@elte.hu>

On 11/11/2009 10:59 PM, Ingo Molnar wrote:
> 
> * Bartlomiej Zolnierkiewicz <bzolnier@gmail.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/
> 
> i think instead of changing 'ht' to 'ht_detect', it would be even more 
> intuitive to only expose the 'ht' flag if the ht-detect capability is 
> there _and_ if the number of siblings is 2 or more.
> 
> That way we dont change it - we just 'hide' the 'ht' string on the 
> category of systems that can enumerate HT via the CPUID but dont 
> actually have HyperThreading.
> 

/proc/cpuinfo is a user-space visible ABI.  Changing it is bad chicken.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


  reply	other threads:[~2009-11-12  7:08 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
2009-11-11 21:35 ` Jeff Garzik
2009-11-12  6:59 ` Ingo Molnar
2009-11-12  7:08   ` H. Peter Anvin [this message]
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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