lkml.org 
[lkml]   [2015]   [Apr]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] x86_64, asm: Work around AMD SYSRET SS descriptor attribute issue
From
Date
I did a microbenchmark in user space... let's see if I can find it.

On April 27, 2015 1:03:29 PM PDT, Borislav Petkov <bp@alien8.de> wrote:
>On Mon, Apr 27, 2015 at 12:59:11PM -0700, H. Peter Anvin wrote:
>> It really comes down to this: it seems older cores from both Intel
>> and AMD perform better with 66 66 66 90, whereas the 0F 1F series is
>> better on newer cores.
>>
>> When I measured it, the differences were sometimes dramatic.
>
>How did you measure that? I should probably do the same on some newer
>AMD machines... We're using k8_nops on all AMD, even though the
>optimization manuals cite different NOPs on newer AMD families.
>
>Thanks.

--
Sent from my mobile phone. Please pardon brevity and lack of formatting.


\
 
 \ /
  Last update: 2015-04-27 22:41    [W:0.130 / U:0.592 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site