lkml.org 
[lkml]   [2020]   [Dec]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] crypto: x86/crc32c-intel - Don't match some Zhaoxin CPUs
On Mon, Dec 14, 2020 at 10:28:19AM +0800, Tony W Wang-oc wrote:
> On 12/12/2020 01:43, Eric Biggers wrote:
> > On Fri, Dec 11, 2020 at 07:29:04PM +0800, Tony W Wang-oc wrote:
> >> The driver crc32c-intel match CPUs supporting X86_FEATURE_XMM4_2.
> >> On platforms with Zhaoxin CPUs supporting this X86 feature, When
> >> crc32c-intel and crc32c-generic are both registered, system will
> >> use crc32c-intel because its .cra_priority is greater than
> >> crc32c-generic. This case expect to use crc32c-generic driver for
> >> some Zhaoxin CPUs to get performance gain, So remove these Zhaoxin
> >> CPUs support from crc32c-intel.
> >>
> >> Signed-off-by: Tony W Wang-oc <TonyWWang-oc@zhaoxin.com>
> >
> > Does this mean that the performance of the crc32c instruction on those CPUs is
> > actually slower than a regular C implementation? That's very weird.
> >
>
> From the lmbench3 Create and Delete file test on those chips, I think yes.
>

Did you try measuring the performance of the hashing itself, and not some
higher-level filesystem operations?

- Eric

\
 
 \ /
  Last update: 2020-12-14 21:45    [W:0.120 / U:0.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site