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- Subject: Re: SipHash for Lua 5.4.0 patch
- From: Gé Weijers <ge@...>
- Date: Mon, 10 Aug 2020 06:51:14 -0700
On Sat, Aug 8, 2020 at 10:16 PM Sam Trenholme <lua@samiam.org> wrote:
>
> > No difference in speed.
>
> Note that there is about a 20% slowdown when we run the same benchmark
> as an i386 binary compiled with GCC 3.2.3 from 2002. SipHash is
> incredibly fast on a modern 64-bit processor because it can run its core
> algorithm using only four 64-bit registers. I would suspect that there
> would be less slowdown on a 32-bit ARM or other RISC architecture
> because they do not have the register starvation i386 has.
On i386-type processors less than 20 years old you could use SSE2
instructions to improve the performance. It won't be as fast as on a
64-bit architecture with plenty of registers, but it would still speed
things up.
Public domain code can be found here: https://github.com/floodyberry/siphash
Gé
