Re: REVISED: Experimentation with Athlon and fast_page_copy

Alan Cox
2001-05-04T21:40:23Z

> prefetch 320(%0) can fetch memory behind the end of the source page.
> Perhaps it accesses memory in the ISA hole, or beyond the end of memory?
> Could you post the e820 map from dmesg?
>
> It's possible to build manually a memory map.
> Could you build one with wide margins from "dangerous" areas? (untested:
> mem=exactmap mem=620k@0 mem=<your mem in MB-2>M@1M)
>
> Then boot with prefetch enabled.

That might not be the actual bug but for rev 1 Athlon it is a real bug. The
first step athlons have an unfortunate problem in that will prefetch
memory marked uncachable and corrupt their caches with it.

Arjan - care to unroll the tail 320 bytes of copying from the main loop ?