From: Ard Biesheuvel <ardb@kernel.org>
To: Herbert Xu <herbert@gondor.apana.org.au>
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 09:04:26 +0200 [thread overview]
Message-ID: <CAMj1kXEdkQUZ_d33N5T5_ELyqRomBKF8Nn+gquo7nrVBMMP-gA@mail.gmail.com> (raw)
In-Reply-To: <20200820070142.GA21343@gondor.apana.org.au>
On Thu, 20 Aug 2020 at 09:01, Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> On Thu, Aug 20, 2020 at 08:58:15AM +0200, Ard Biesheuvel wrote:
> >
> > But if we look at the actual issue at hand, we might also look into
> > amortizing the FPU preserve/restore over multiple invocations of a
> > cipher. I proposed a patch a while ago that makes cipher an internal
> > crypto API abstraction, and we could easily add pre/post hooks that
> > preserve/restore the FPU in this case, in which case we would not need
> > any changes at higher levels.
>
> I think any use of SIMD crypto_cipher on bulk data is just wrong.
> Because the performance degradation when SIMD cannot be used is
> too great for this to make sense.
>
> So optimising the FPU overhead is attacking the wrong problem.
>
I don't disagree with that, especially given all the effort that went
into optimizing FPU preserve/restore on both arm64 and x86. But the
bottom line is that this is what is causing the degradation in Ben's
case, so we cannot disregard it.
next prev parent reply other threads:[~2020-08-20 7:04 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 [this message]
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
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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