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

2016-12-21 Thread Rik van Riel
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: > >   Pentium Core 2  Ivy > >   4   Duo Bridge > > SipHash-2-4 

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

2016-12-21 Thread Rik van Riel
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 ru

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

2016-12-21 Thread Eric Dumazet
On Wed, 2016-12-21 at 11:39 -0500, Rik van Riel wrote: > 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. Well, maybe they have millions of units to replace. > >

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

2016-12-21 Thread Jason A. Donenfeld
On Wed, Dec 21, 2016 at 11:27 PM, Theodore Ts'o wrote: > And "with enough registers" includes ARM and MIPS, right? So the only > real problem is 32-bit x86, and you're right, at that point, only > people who might care are people who are using a space-radiation > hardened 386 --- and they're not

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

2016-12-21 Thread George Spelvin
> Plus the benchmark was bogus anyway, and when I built a more specific > harness -- actually comparing the TCP sequence number functions -- > SipHash was faster than MD5, even on register starved x86. So I think > we're fine and this chapter of the discussion can come to a close, in > order to mov

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

2016-12-21 Thread Jason A. Donenfeld
Hi George, On Thu, Dec 22, 2016 at 4:55 AM, George Spelvin wrote: > Do we have to go through this? No, the benchmark was *not* bogus. > Then I replaced the kernel #includes with the necessary typedefs > and #defines to make it compile in user-space. > * I didn't iterate 100K times, I timed the f