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Subject: [PATCHv2 0/2] Add max CPU nodes field to ibm,client-architecture call
From: Joel Schopp <jschopp@austin.ibm.com>
To: linuxppc-dev@ozlabs.org
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References: <1263501508.4869.133.camel@jschopp-laptop>
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Date: Mon, 01 Feb 2010 16:50:39 -0600
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Large NUMA machines require Linux to indicate support for more than 64
cpu cores.  This is done through the ibm,client-architecture call, and
is documented in the PAPR.  There is also another new field added to
indicate that the OS is Linux as a hint for possible future performance
settings.

The first patch attempts to statically initialize the number of
supported cores with NR_CPUS, the maximum Linux could boot if the cpus
did not have multi-threading (SMT).  It can overestimate by the factor
of SMT.  For instance on Power6 with 2 way SMT it would overestimate by
a factor of 2.  The result of this overestimation is that Linux might
not be able boot all the cpus assigned to it, but would still boot
NR_CPUS worth of SMT threads.

The second patch adjusts for SMT by reading the device tree before
unflattening.  

I've updated patch 1 from previous comments. Patch 1 can be taken on its
own if Patch 2 seems like overkill.  

v2 - Updated patch 2 style and messages.  Basic functionality is the
same as v1.