Re: Intel vs AMD x86-64

Albert Cahalan
2004-02-24T17:32:55Z

On Tue, 2004-02-24 at 11:44, Dave Jones wrote:
> On Mon, Feb 23, 2004 at 09:42:05PM -0500, Albert Cahalan wrote:
> > Setting up only one of the IO-MMUs would be neat.
>
> AGPv3 standard mandates that you MUST keep all GARTs coherent,
> so this isn't possible. The amd64 GART driver goes to great
> lengths to make sure it does update the northbridges on every
> CPU whenever something changes.

Of course. That's the easy way; you won't need
to worry about memory interleave or out-of-bounds
prefetch if you keep everything coherent.

I'm just saying it would be neat, and potentially
useful, to intentionally violate this. Of greatest
interest would be the 2-way Opteron boards that
only have RAM connected to the CPU closest to PCI.
The sidecar CPU :-) could be ignored.