From: Sandy Harris <sandyinchina@gmail.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>,
"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: Wed, 2 Nov 2016 16:47:33 -0400 [thread overview]
Message-ID: <CACXcFmnEWbGmBc-RmkuOacVVH5sVtdC8ca7Jgbqx2+6TmTPzCg@mail.gmail.com> (raw)
In-Reply-To: <20161102200959.GA23297@gondor.apana.org.au>
On Wed, Nov 2, 2016 at 4:09 PM, Herbert Xu <herbert@gondor.apana.org.au> wrote:
> On Wed, Nov 02, 2016 at 06:58:10PM +0100, Jason A. Donenfeld wrote:
>> On MIPS chips commonly found in inexpensive routers, this makes a big
>> difference in performance.
>>
>> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
>
> Can you give some numbers please? What about other architectures
> that your patch impacts?
In general it is not always clear that using whatever hardware crypto
is available is a good idea. Not all such hardware is fast, some CPUs
are, some CPUs have hardware for AES, and even if the hardware is
faster than the CPU, the context switch overheads may exceed the
advantage.
Ideally the patch development or acceptance process would be
testing this, but I think it might be difficult to reach that ideal.
The exception is a hardware RNG; that should always be used unless
it is clearly awful. It cannot do harm, speed is not much of an issue,
and it solves the hardest problem in the random(4) driver, making
sure of correct initialisation before any use.
next prev parent reply other threads:[~2016-11-02 20:47 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 [this message]
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
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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