From: "H. Peter Anvin" <hpa@zytor.com>
To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org,
konrad.wilk@oracle.com, torvalds@linux-foundation.org,
JBeulich@suse.com, jbeulich@suse.com, tglx@linutronix.de
Cc: linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/asm] x86/xor: Make virtualization friendly
Date: Fri, 25 Jan 2013 14:11:09 -0800 [thread overview]
Message-ID: <510302FD.3090009@zytor.com> (raw)
In-Reply-To: <tip-05fbf4d6fc6a3c0c3e63b77979c9311596716d10@git.kernel.org>
On 01/25/2013 02:43 AM, tip-bot for Jan Beulich wrote:
> Commit-ID: 05fbf4d6fc6a3c0c3e63b77979c9311596716d10
> Gitweb: http://git.kernel.org/tip/05fbf4d6fc6a3c0c3e63b77979c9311596716d10
> Author: Jan Beulich <JBeulich@suse.com>
> AuthorDate: Fri, 2 Nov 2012 14:21:23 +0000
> Committer: Ingo Molnar <mingo@kernel.org>
> CommitDate: Fri, 25 Jan 2013 09:23:51 +0100
>
> x86/xor: Make virtualization friendly
>
> In virtualized environments, the CR0.TS management needed here
> can be a lot slower than anticipated by the original authors of
> this code, which particularly means that in such cases forcing
> the use of SSE- (or MMX-) based implementations is not desirable
> - actual measurements should always be done in that case.
>
> For consistency, pull into the shared (32- and 64-bit) header
> not only the inclusion of the generic code, but also that of the
> AVX variants.
>
This patch is wrong and should be dropped. I verified it with the KVM
people that they do NOT want this change. It is a Xen-specific problem.
-hpa
next prev parent reply other threads:[~2013-01-25 22:11 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-02 14:21 [PATCH 3/3, v2] x86/xor: make virtualization friendly Jan Beulich
2012-11-02 17:30 ` H. Peter Anvin
2012-11-05 9:10 ` Jan Beulich
2013-01-25 10:43 ` [tip:x86/asm] x86/xor: Make " tip-bot for Jan Beulich
2013-01-25 22:11 ` H. Peter Anvin [this message]
2013-01-25 22:15 ` H. Peter Anvin
2013-01-26 1:05 ` H. Peter Anvin
2013-01-26 16:49 ` KY Srinivasan
2013-01-26 12:10 ` Ingo Molnar
2013-01-28 9:04 ` Jan Beulich
2013-01-28 15:26 ` H. Peter Anvin
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