From: Christian Weisgerber <naddy@mips.inka.de>
Subject: Re: [PATCH] amd64: import optimized memcmp from FreeBSD
To: tech@openbsd.org
Date: Sat, 30 Nov 2024 15:59:56 +0100

Christian Schulte:

> lately I thought about rewriting those functions to use simd, but never
> looked further into doing it, because I do not know if simd
> registers/instructions could be used there at all. Could they? Instead

Presumably not in the kernel as we would have to save/restore
FPU/SIMD registers around those calls.

> of working on the same thing every now and then, I would be in favour of
> providing routines using the most performant instructions the
> architecture has to offer (simd), if possible, and be done with it.
> Would not mind writing those, if they would be accepted.

FreeBSD already did all that work recently.
https://freebsdfoundation.org/blog/a-sneak-peek-simd-enhanced-string-functions-for-amd64/

-- 
Christian "naddy" Weisgerber                          naddy@mips.inka.de