Re: [Bug 350] New: i386 context switch very slow compared to 2.4 due to wrmsr (performance)

H. Peter Anvin
2003-03-19T00:32:04Z

Followup to: <Pine.LNX.4.44.0303181113590.13708-100000@home.transmeta.com>
By author: Linus Torvalds <torvalds@transmeta.com>
In newsgroup: linux.dev.kernel
>
> Wow. There aren't many things that AMD tends to show the P4-like "big
> latency in rare cases" behaviour.
>
> But quite honestly, I think they made the right call, and I _expect_ that
> of modern CPU's. The fact is, modern CPU's tend to need to pre-decode the
> instruction stream some way, and storing to it while running from it is
> just a really really bad idea. And since it's so easy to avoid it, you
> really just shouldn't do it.
>

AMD, I believe, has an "annotated" icache.

-hpa
--
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
Architectures needed: ia64 m68k mips64 ppc ppc64 s390 s390x sh v850 x86-64