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From: Herbert Xu <herbert@gondor.apana.org.au>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: "David S. Miller" <davem@davemloft.net>,
	linux-crypto@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	Martin Willi <martin@strongswan.org>
Subject: Re: [PATCH] poly1305: generic C can be faster on chips with slow unaligned access
Date: Thu, 3 Nov 2016 08:49:34 +0800	[thread overview]
Message-ID: <20161103004934.GA30775@gondor.apana.org.au> (raw)
In-Reply-To: <CAHmME9ogYTGFaNDt1CD0FxEHxDzVhNX=AN3_PH3t=0zREGgYPA@mail.gmail.com>

On Wed, Nov 02, 2016 at 11:00:00PM +0100, Jason A. Donenfeld wrote:
>
> Just tested. I get a 6% slowdown on my Skylake. No good. I think it's
> probably best to have the two paths in there, and not reduce it to
> one.

FWIW I'd rather live with a 6% slowdown than having two different
code paths in the generic code.  Anyone who cares about 6% would
be much better off writing an assembly version of the code.

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:[~2016-11-03  0:49 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-02 17:58 [PATCH] poly1305: generic C can be faster on chips with slow unaligned access Jason A. Donenfeld
2016-11-02 20:09 ` Herbert Xu
2016-11-02 20:47   ` Sandy Harris
2016-11-02 21:06   ` Jason A. Donenfeld
2016-11-02 21:08     ` Herbert Xu
2016-11-02 21:25       ` Jason A. Donenfeld
2016-11-02 21:26         ` Herbert Xu
2016-11-02 22:00           ` Jason A. Donenfeld
2016-11-03  0:49             ` Herbert Xu [this message]
2016-11-03  7:24               ` Jason A. Donenfeld
2016-11-03 17:08                 ` David Miller
2016-11-03 22:20                   ` Jason A. Donenfeld
2016-11-04 17:37                     ` Eric Biggers
2016-11-07 18:08                       ` Jason A. Donenfeld
2016-11-07 18:23                         ` Jason A. Donenfeld
2016-11-07 18:26                         ` Eric Biggers
2016-11-07 19:02                           ` Jason A. Donenfeld
2016-11-07 19:25                             ` Eric Biggers
2016-11-07 19:41                               ` Jason A. Donenfeld
2016-11-07 19:12 ` [PATCH v2] " Jason A. Donenfeld
2016-11-07 19:43   ` [PATCH v3] " Jason A. Donenfeld
2016-11-12 23:27     ` kbuild test robot
2016-11-07 19:47   ` [PATCH v4] " Jason A. Donenfeld
2016-11-07 20:40     ` Eric Biggers
2016-11-08  7:52     ` Martin Willi
2016-11-08 17:26       ` Eric Biggers
2016-11-13 11:29     ` Herbert Xu

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