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SubjectRe: [tip:x86/asm] x86/xor: Make virtualization friendly
On 01/25/2013 02:11 PM, H. Peter Anvin wrote:
> 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.
>

FWIW: I have dropped this patch from tip:x86/asm.

-hpa




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