Re: [kernel-hardening] Re: HalfSipHash Acceptable Usage

From: Rik van Riel
Date: Wed Dec 21 2016 - 11:39:57 EST


On Wed, 2016-12-21 at 07:56 -0800, Eric Dumazet wrote:
> On Wed, 2016-12-21 at 15:42 +0100, Jason A. Donenfeld wrote:
> George said :
>
> > Cycles per byte on 1024 bytes of data:
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂPentium Core 2ÂÂIvy
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ4ÂÂÂÂÂÂÂDuoÂÂÂÂÂBridge
> > SipHash-2-4ÂÂÂÂÂÂÂÂÂÂÂ38.9ÂÂÂÂÂ8.3ÂÂÂÂÂ5.8
> > HalfSipHash-2-4ÂÂÂÂÂÂÂ12.7ÂÂÂÂÂ4.5ÂÂÂÂÂ3.2
> > MD5ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ8.3ÂÂÂÂÂ5.7ÂÂÂÂÂ4.7
>
>
> That really was for 1024 bytes blocks, so pretty much useless for our
> discussion ?
>
> Reading your numbers last week, I thought SipHash was faster, but
> George
> numbers are giving the opposite impression.
>
> I do not have a P4 to make tests, so I only can trust you or George.

Does anybody still have a P4?

If they do, they're probably better off replacing
it with an Atom. The reduced power bills will pay
for replacing that P4 within a year or two.

In short, I am not sure how important the P4
performance numbers are, especially if we can
improve security for everybody else...

--
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