linux-kernel - Re: [PATCH] crypto: x86/crc32c-intel

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Date:   Sun, 3 Jan 2021 08:12:00 +1100
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     Tony W Wang-oc <TonyWWang-oc@...oxin.com>
Cc:     davem@...emloft.net, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, x86@...nel.org, hpa@...or.com,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        TimGuo-oc@...oxin.com, CooperYan@...oxin.com,
        QiyuanWang@...oxin.com, HerryYang@...oxin.com,
        CobeChen@...oxin.com, SilviaZhao@...oxin.com
Subject: Re: [PATCH] crypto: x86/crc32c-intel - Don't match some Zhaoxin CPUs

On Tue, Dec 15, 2020 at 06:28:11PM +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.
> 
> When doing lmbench3 Create and Delete file test on partitions with
> ext4 enabling metadata checksum, found using crc32c-generic driver
> could get about 20% performance gain than using the driver crc32c-intel
> on some Zhaoxin CPUs.
> 
> This case expect to use crc32c-generic driver for these Zhaoxin CPUs
> to get performance gain, so remove these Zhaoxin CPUs support from
> crc32c-intel.
> 
> Signed-off-by: Tony W Wang-oc <TonyWWang-oc@...oxin.com>
> ---
>  arch/x86/crypto/crc32c-intel_glue.c | 21 +++++++++++++++++++--
>  1 file changed, 19 insertions(+), 2 deletions(-)

This does not seem to address the latest comment from hpa.

Thanks,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt