Messages in this thread | | | Date | Mon, 14 Dec 2020 12:41:18 -0800 | From | Eric Biggers <> | Subject | Re: [PATCH] crypto: x86/crc32c-intel - Don't match some Zhaoxin CPUs |
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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
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