Re: interrupt locality for NUMA

From: Alex Williamson <>
Date: 2004-08-14 01:41:11
On Fri, 2004-08-13 at 08:32 -0700, Jesse Barnes wrote:
> On Thursday, August 12, 2004 7:58 pm, Alex Williamson wrote:
> >    This probably isn't ready for inclusion yet, but I wanted to see if
> > anybody else could make use of it.  This works on HP sx1000 boxes setup
> > for NUMA and I think it's ACPI namespace does the right thing.  All this
> > does is walk through namespace looking for devices with an _MAT method
> > that returns an IOSAPIC and also has a _PXM method to tell us the
> > proximity domain where it lives.  The node data gets stored in the
> > iosapic data structure because doing this lookup is pretty slow.  Does
> > this jive with what other ACPI NUMA boxes are exporting in namespace?
> > I'm hoping everyone will put the _PXM on the same device as the _MAT,
> > but I'm wondering if I need to add support for looking on parent
> > objects.  Thoughts?  Thanks,
> Matt Dobson is working on a pci_to_nodemask, might that be used instead?  If 
> we did it that way, we could put it in generic code, dependent on CONFIG_NUMA 
> or something, rather than keeping it ACPI specific.

   We certainly need a pci to node mapping, but I'm not sure we want to
use it for interrupt routing.  For instance, how would a non-pci serial
port get assigned to the right node?  Not that this example is terribly
important, but not everything is pci.


Alex Williamson                             HP Linux & Open Source Lab

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Received on Fri Aug 13 11:41:42 2004

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