Re: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata
From: Jamie Lokier
Date: Thu Sep 11 2003 - 12:54:07 EST
Andi Kleen wrote:
> signal exception path is thousands of cycles, we're talking about tens
> of cycles here.
<hand-waving>
Tens vs thousands == percentage points.
Isn't it about 20 cycles per mispredicted branch on a P4?
Five of those and we're talking several percent slowdown, ridiculous
as it seems.
</hand-waving>
-- Jamie
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