From: Rik van Riel <riel@redhat.com>
To: kernel-hardening@lists.openwall.com, Jason@zx2c4.com,
linux@sciencehorizons.net
Cc: ak@linux.intel.com, davem@davemloft.net, David.Laight@aculab.com,
djb@cr.yp.to, ebiggers3@gmail.com, eric.dumazet@gmail.com,
hannes@stressinduktion.org, jeanphilippe.aumasson@gmail.com,
linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
luto@amacapital.net, netdev@vger.kernel.org, tom@herbertland.com,
torvalds@linux-foundation.org, tytso@mit.edu,
vegard.nossum@gmail.com
Subject: Re: [kernel-hardening] Re: HalfSipHash Acceptable Usage
Date: Wed, 21 Dec 2016 11:41:28 -0500 [thread overview]
Message-ID: <1482338488.11006.70.camel@redhat.com> (raw)
In-Reply-To: <20161221155540.29529.qmail@ns.sciencehorizons.net>
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On Wed, 2016-12-21 at 10:55 -0500, George Spelvin wrote:
> Actually, DJB just made a very relevant suggestion.
>
> As I've mentioned, the 32-bit performance problems are an x86-
> specific
> problem. ARM does very well, and other processors aren't bad at all.
>
> SipHash fits very nicely (and runs very fast) in the MMX registers.
>
> They're 64 bits, and there are 8 of them, so the integer registers
> can
> be reserved for pointers and loop counters and all that. And there's
> reference code available.
>
> How much does kernel_fpu_begin()/kernel_fpu_end() cost?
Those can be very expensive. Almost certainly not
worth it for small amounts of data.
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next prev parent reply other threads:[~2016-12-21 16:46 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-19 17:32 HalfSipHash Acceptable Usage Jason A. Donenfeld
[not found] ` <CAGiyFdduUNSGq24zfsk0ZU=hnOCmewAw8vw6XvDoS-3f+3UPKQ@mail.gmail.com>
2016-12-19 21:00 ` Jason A. Donenfeld
2016-12-20 21:36 ` Theodore Ts'o
2016-12-20 23:07 ` George Spelvin
2016-12-20 23:55 ` Eric Dumazet
2016-12-21 3:28 ` George Spelvin
2016-12-21 5:29 ` Eric Dumazet
2016-12-21 6:34 ` George Spelvin
2016-12-21 14:24 ` Jason A. Donenfeld
2016-12-21 15:55 ` George Spelvin
2016-12-21 16:37 ` Jason A. Donenfeld
2016-12-21 16:41 ` Rik van Riel [this message]
2016-12-21 17:25 ` Linus Torvalds
2016-12-21 18:07 ` George Spelvin
2016-12-22 1:54 ` Andy Lutomirski
2016-12-21 14:42 ` Jason A. Donenfeld
2016-12-21 15:56 ` Eric Dumazet
2016-12-21 16:33 ` Jason A. Donenfeld
2016-12-21 16:39 ` [kernel-hardening] " Rik van Riel
2016-12-21 17:08 ` Eric Dumazet
2016-12-21 18:37 ` George Spelvin
2016-12-21 18:40 ` Jason A. Donenfeld
2016-12-21 22:27 ` Theodore Ts'o
2016-12-22 0:18 ` George Spelvin
2016-12-22 1:13 ` George Spelvin
2016-12-21 22:29 [kernel-hardening] " Jason A. Donenfeld
2016-12-22 3:55 ` George Spelvin
2016-12-22 4:40 ` Jason A. Donenfeld
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