Re: [PATCH] crypto: x86/crc32c-intel - Don't match some Zhaoxin CPUs

[Eric Biggers]

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@xxxxxxxxxxx>

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.

- Eric