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To: linux-kernel@vger.kernel.org
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [Bug 350] New: i386 context switch very slow compared to 2.4
 due to wrmsr (performance)
Date: 18 Mar 2003 16:42:29 -0800
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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
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