From: Dave Jones <davej@codemonkey.org.uk>
To: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC] x86: fix confusing name of /proc/cpuinfo "ht" flag
Date: Thu, 12 Nov 2009 13:37:18 -0500 [thread overview]
Message-ID: <20091112183718.GA1925@codemonkey.org.uk> (raw)
In-Reply-To: <20091112175908.GB20542@elte.hu>
On Thu, Nov 12, 2009 at 06:59:08PM +0100, Ingo Molnar wrote:
> > It's an ABI. Keep it stable, please.
>
> That's generally true, but i'm not suggesting that: i'm suggesting to
> _clear_ the HT flag from the cpufeatures if there's only one sibling.
> It's meaningless in that case and as the link quoted by the original
> patch shows many people are confused by that.
>
> I have such a box so i can test it. (but i dont expect any problems)
I agree that it's an ABI change, but any software depending on its current
state has to implement a fallback for the case where 'ht' isn't present anyway
unless there's some program that only runs on ht capable hardware, which
sounds just crazy.
The only potential for breakage that I can see is that code that is tuned
to be run in the HT case will stop running in cases where it shouldn't.
Which sounds like a positive thing to me.
Dave
--
http://www.codemonkey.org.uk
next prev parent reply other threads:[~2009-11-12 19:09 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
2009-11-12 17:59 ` Ingo Molnar
2009-11-12 18:37 ` Dave Jones [this message]
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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