Re: [tip:sched/core] x86/numa: Allow specifying node_distance() for numa=fake

Ingo Molnar
2012-06-06T07:11:24Z

* David Rientjes <rientjes@google.com> wrote:

> On Wed, 9 May 2012, tip-bot for Peter Zijlstra wrote:
>
> > Commit-ID: 94c0dd3278dd3eae52eabf0fb77d472d0dd3e373
> > Gitweb: http://git.kernel.org/tip/94c0dd3278dd3eae52eabf0fb77d472d0dd3e373
> > Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > AuthorDate: Wed, 18 Apr 2012 19:04:17 +0200
> > Committer: Ingo Molnar <mingo@kernel.org>
> > CommitDate: Wed, 9 May 2012 13:28:59 +0200
> >
> > x86/numa: Allow specifying node_distance() for numa=fake
> >
> > Allows emulating more interesting NUMA configurations like a quad
> > socket AMD Magny-Cour:
> >
> > "numa=fake=8:10,16,16,22,16,22,16,22,
> > 16,10,22,16,22,16,22,16,
> > 16,22,10,16,16,22,16,22,
> > 22,16,16,10,22,16,22,16,
> > 16,22,16,22,10,16,16,22,
> > 22,16,22,16,16,10,22,16,
> > 16,22,16,22,16,22,10,16,
> > 22,16,22,16,22,16,16,10"
> >
> > Which has a non-fully-connected topology.
> >
>
> I like this support and I'm pretty sure you used it to
> reproduce my problems with sched/numa locally, but I think it
> would be better to seperate it out as a different parameter
> such as slit=fake so that we can still use it to fake the SLIT
> of our NUMA machines without requiring numa=fake which
> provides no guarantees to break the nodes along physical
> boundaries.
>
> So without seperating it out into slit=fake, we can't change
> this information without changing the SLIT itself and that
> makes debugging harder.

Makes sense - wanna send a patch?

Thanks,

Ingo