lkml.org 
[lkml]   [2015]   [May]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRE: [PATCH v2 0/6] powerpc32: replace memcpy and memset by cacheable alternatives
Date
From: Christophe Leroy
> Sent: 19 May 2015 11:08
>
> This patchset implements use of cacheable versions of memset and
> memcpy since when the destination is not cacheable, memset_io
> and memcpy_toio are used.

This isn't the right list to ask, but:

Can someone fix the x86 versions of memset/memcpy (and the _io variants)
so that they don't end up being 'rep movsb' on new intel cpus?

I've a C2558 Atom which has the optimised 'rep movsb' hardware.
Copies to/from uncached locations are now done 'byte by byte'.
As well as kernel code this affects userpace copying to/from
mmap()ed PCIe space.
64bit reads are slow enough, making it 8 times slower is horrid.

I suspect this affect some network drivers as well.

David

\
 
 \ /
  Last update: 2015-05-19 14:01    [W:0.042 / U:0.652 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site