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: Thu, 12 Nov 2009 07:18:36 -0800 [thread overview]
Message-ID: <4AFC274C.2020209@zytor.com> (raw)
In-Reply-To: <20091112081317.GB25345@elte.hu>
On 11/12/2009 12:13 AM, Ingo Molnar wrote:
>>
>> /proc/cpuinfo is a user-space visible ABI. Changing it is bad
>> chicken.
>
> Almost ... something is only an ABI if an actual application relies on
> the 'ht' flag being there on non-hyperthreading CPUs. We dont know
> whether there's any, but the likelyhood looks pretty low. Could park it
> a branch for some time to see whether anything trips up.
>
No, please. We have had people who have "helpfully" tried to change
/proc/cpuinfo in the past, and what we find is that application
developers don't tell us -- they grumble among themselves and put out a
new release saying "fixes breakage introduced by Linux ..."
It's an ABI. Keep it stable, please.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2009-11-12 15:19 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
2009-11-12 8:13 ` Ingo Molnar
2009-11-12 15:18 ` H. Peter Anvin [this message]
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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