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From: Herbert Xu <herbert@gondor.apana.org.au>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Ben Greear <greearb@candelatech.com>,
	Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
	Eric Biggers <ebiggers@kernel.org>
Subject: Re: [PATCH 0/5] crypto: Implement cmac based on cbc skcipher
Date: Thu, 20 Aug 2020 17:44:14 +1000	[thread overview]
Message-ID: <20200820074414.GA21848@gondor.apana.org.au> (raw)
In-Reply-To: <CAMj1kXFR2SSdE7oi6YKsWG1OvpXpo+584XSiMCSL0V-ysOMc5A@mail.gmail.com>

On Thu, Aug 20, 2020 at 09:33:21AM +0200, Ard Biesheuvel wrote:
>
> > On my machine the performance difference on a 1472-byte request
> > between SIMD and generic is 2161 vs. 7558 (cycles).
> 
> Sure. But your machine does not have the pathological FPU
> preserve/restore performance.

Why does that matter? These are numbers for cbc-aesni which means
just a single preserve/restore for the whole request.

Or are you saying on Ben's machine cbc-aesni would have worse
performance vs. aes-generic?
 
> The mac80211 CCMP code uses a synchronous ccm aead, which gets backed
> by a skcipher+ahash combo by the ccm template. So a synchronous ahash
> is fine for this particular case.

OK I was just grepping for cmac so didn't see this.

For this case, I think it's even more important that it be converted
over to async because its sending path is also in user context just
like IPsec.

So simply by sending wireless packets you can hog the CPU while
doing SIMD in kernel context which would then kill the receive
path if you're using the generic fallback.

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

  reply	other threads:[~2020-08-20  7:44 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-02  9:06 [PATCH] crypto: x86/aesni - implement accelerated CBCMAC, CMAC and XCBC shashes Ard Biesheuvel
2020-08-03 19:11 ` Ben Greear
2020-08-04 12:55   ` Ard Biesheuvel
2020-08-04 13:01     ` Ben Greear
2020-08-04 13:08       ` Ard Biesheuvel
2020-08-04 13:22         ` Ben Greear
2020-08-04 19:45         ` Ben Greear
2020-08-04 20:12           ` Ard Biesheuvel
2020-09-23 11:03           ` Ben Greear
2020-10-29 16:58             ` Ard Biesheuvel
2020-08-18  8:24 ` [PATCH 0/5] crypto: Implement cmac based on cbc skcipher Herbert Xu
2020-08-18  8:25   ` [PATCH 1/6] crypto: skcipher - Add helpers for sync skcipher spawn Herbert Xu
2020-08-18  8:25   ` [PATCH 2/6] crypto: ahash - Add helper to free single spawn instance Herbert Xu
2020-08-18  8:25   ` [PATCH 3/6] crypto: ahash - Add init_tfm/exit_tfm Herbert Xu
2020-08-18  8:25   ` [PATCH 4/6] crypto: ahash - Add ahash_alg_instance Herbert Xu
2020-08-18  8:25   ` [PATCH 5/6] crypto: ahash - Remove AHASH_REQUEST_ON_STACK Herbert Xu
2020-08-26 10:55     ` Ard Biesheuvel
2020-08-18  8:25   ` [PATCH 6/6] crypto: cmac - Use cbc skcipher instead of raw cipher Herbert Xu
2020-08-24  9:47     ` Ard Biesheuvel
2020-08-24 11:20       ` Herbert Xu
2020-08-18  8:31   ` [PATCH 0/5] crypto: Implement cmac based on cbc skcipher Ard Biesheuvel
2020-08-18 13:51     ` Herbert Xu
2020-08-18 13:56       ` Ben Greear
2020-08-18 14:05         ` Herbert Xu
2020-08-18 14:17           ` Ben Greear
2020-08-18 22:15             ` Herbert Xu
2020-08-18 22:27               ` Herbert Xu
2020-08-18 22:31                 ` Ben Greear
2020-08-18 22:33                   ` Herbert Xu
2020-08-18 22:39                     ` Ben Greear
2020-08-20  6:58                       ` Ard Biesheuvel
2020-08-20  7:01                         ` Herbert Xu
2020-08-20  7:04                           ` Ard Biesheuvel
2020-08-20  7:06                             ` Herbert Xu
2020-08-20  7:19                               ` Ard Biesheuvel
2020-08-20  7:29                                 ` Herbert Xu
2020-08-20  7:33                                   ` Ard Biesheuvel
2020-08-20  7:44                                     ` Herbert Xu [this message]
2020-08-20  7:48                                       ` Ard Biesheuvel
2020-08-20  7:53                                         ` Herbert Xu
2020-08-20  7:56                                           ` Ard Biesheuvel
2020-08-20 13:54                                             ` Ben Greear
2020-08-20 20:10                                               ` Herbert Xu
2020-08-20 22:09                                                 ` Ben Greear
2020-08-20 22:12                                                   ` Herbert Xu
2020-08-22 22:35                 ` Christian Lamparter

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