Re: [PATCH] fix build_zonelists for CONFIG_ACPI_NUMA

Jesse Barnes
2003-09-19T17:07:07Z

On Fri, Sep 19, 2003 at 06:56:21PM +0200, Erich Focht wrote:
> On Thursday 18 September 2003 21:59, Jesse Barnes wrote:
> > ACPI 2.0 SLIT locality table:
> > 010 020 022 042
> > 020 010 042 022
> > 022 042 010 020
> > 042 022 020 010
>
> That unsymmetric??? Interesting... Of course this saves you the
> headache of explicitely round-robin.

This is just a small system, only 8p, and I was wrong when I said that
we wouldn't have SLIT tables like the one below. On a larger system
(above 8 nodes) we'll have 4 nodes in each proximity domain, so
round-robin would help us there. The system above has a topology like
this:

------ fast ------
| |__v___| |
| 3 | | 2 |
------ ------
| <- slow -> |
------ ------
| |______| |
| 1 | ^ | 0 |
------ fast ------

Which explains the SLIT. Of course, on a larger system we'd have the
slow links all connect to a router, which would mean we'd have multiple
nodes in the same domain.

> > Which I think you were worried about?
>
> I'm still worried about the "normal" kind of machines with more
> symmetric node-distances. TX-7 for example has

Yeah, sorry. I was smokin' something when I posted that message. I
really do understand the issue and agree that it's a problem that we
should fix :)

> 10 15 15 15 20 20 20 20
> 15 10 15 15 20 20 20 20
> 15 15 10 15 20 20 20 20
> 15 15 15 10 20 20 20 20
> 20 20 20 20 10 15 15 15
> 20 20 20 20 15 10 15 15
> 20 20 20 20 15 15 10 15
> 20 20 20 20 15 15 15 10

Thanks,
Jesse