From: Tony W Wang-oc <TonyWWang-oc@zhaoxin.com>
To: Eric Biggers <ebiggers@kernel.org>
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 10:28:19 +0800 [thread overview]
Message-ID: <1f8d17bf-c1d9-6496-d2f8-5773633011fb@zhaoxin.com> (raw)
In-Reply-To: <X9Ov3RWDpUik7gXo@sol.localdomain>
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.
sincerely
Tony
next prev parent reply other threads:[~2020-12-14 2:29 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 [this message]
2020-12-14 20:41 ` Eric Biggers
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
-- strict thread matches above, loose matches on Subject: below --
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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