Re: [PATCH] POWER 4 fails to boot with NUMA

[Sonny Rao]

On Mon, Aug 01, 2005 at 12:27:42AM -0500, Paul Mackerras wrote:
> From: Mike Kravetz <kravetz@xxxxxxxxxx>
> 
> If CONFIG_NUMA is set, some POWER 4 systems will fail to boot.  This is
> because of special processing needed to handle invalid node IDs (0xffff)
> on POWER 4.  My previous patch to handle memory 'holes' within nodes
> forgot to add this special case for POWER 4 in one place.
> 
> In reality, I'm not sure that configuring the kernel for NUMA on POWER 4
> makes much sense.  Are there POWER 4 based systems with NUMA characteristics
> that are presented by the firmware?  But, distros want one kernel for all
> systems so NUMA is on by default in their kernels.  The patch handles those
> cases.

IIRC, In SMP mode the NUMA topology is exported.  I've tried this on a
p690 and it worked correctly on older kernels (2.6.10 or 2.6.11) 

I also noticed a nice speedup on a few things compared to LPAR mode :-)

Sonny
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