Re: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata

Jamie Lokier
2003-09-11T17:51:41Z

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