From: Eric Biggers <ebiggers@kernel.org>
To: Tony W Wang-oc <TonyWWang-oc@zhaoxin.com>
Cc: herbert@gondor.apana.org.au, davem@davemloft.net,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
x86@kernel.org, hpa@zytor.com, linux-crypto@vger.kernel.org,
linux-kernel@vger.kernel.org, TimGuo-oc@zhaoxin.com,
CooperYan@zhaoxin.com, QiyuanWang@zhaoxin.com,
HerryYang@zhaoxin.com, CobeChen@zhaoxin.com,
SilviaZhao@zhaoxin.com
Subject: Re: [PATCH] crypto: x86/crc32c-intel - Don't match some Zhaoxin CPUs
Date: Mon, 14 Dec 2020 12:41:18 -0800 [thread overview]
Message-ID: <X9fN7mOMdn1Dxn63@sol.localdomain> (raw)
In-Reply-To: <1f8d17bf-c1d9-6496-d2f8-5773633011fb@zhaoxin.com>
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
next prev parent reply other threads:[~2020-12-14 20:42 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-11 11:29 [PATCH] crypto: x86/crc32c-intel - Don't match some Zhaoxin CPUs Tony W Wang-oc
2020-12-11 13:00 ` Peter Zijlstra
2020-12-12 4:32 ` Tony W Wang-oc
2020-12-11 17:43 ` Eric Biggers
2020-12-12 9:36 ` Ard Biesheuvel
2020-12-12 10:54 ` Ard Biesheuvel
2020-12-14 2:29 ` Tony W Wang-oc
2020-12-14 2:28 ` Tony W Wang-oc
2020-12-14 20:41 ` Eric Biggers [this message]
2020-12-15 2:15 ` Tony W Wang-oc
2020-12-15 17:56 ` Eric Biggers
2020-12-21 2:46 ` tonywwang-oc
2020-12-21 19:27 ` hpa
2020-12-22 3:01 ` tonywwang-oc
2020-12-22 4:54 ` hpa
2021-01-07 6:23 ` Tony W Wang-oc
2020-12-14 3:59 Tony W Wang-oc
2020-12-15 8:58 ` Peter Zijlstra
2020-12-15 10:02 ` Tony W Wang-oc
2020-12-15 10:28 Tony W Wang-oc
2021-01-02 21:12 ` Herbert Xu
2021-01-07 6:27 ` Tony W Wang-oc
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