Messages in this thread | | | Date | Sat, 13 Sep 2003 18:54:25 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata |
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Hi!
> > > > > What's wrong with the current status quo that just says > > > > > "Athlon prefetch is broken"? > > > > It doesn't fix user space for once. > > > > > > And for another, it cripples the earlier athlons which > > > don't have this > > > errata. Andi's fix at least makes prefetch work again on > > > those boxes. > > > It's also arguable that prefetch() helps the older K7's > > > more than the > > > affected ones. > > > > All Athlons have this Errata. I can trigger it on an old > > 900Mhz pre XP Athlon too. You just have to use 3dnow prefetch > > instead of SSE prefetch. > > > > BTW the older Athlons currently don't use prefetch because > > the alternative > > patcher does not handle 3dnow style prefetch. > > > > Avoiding prefetch for all Athlons and earlier Opterons/Athlon64 > even in the kernel can really tank performance. And as Andi says > it still doesn't solve user mode from hitting the errata.
How much speedups can be expected from prefetch? 5%? Pavel -- When do you have a heart between your knees? [Johanka's followup: and *two* hearts?] - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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