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@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. > > > > 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
