Debian stock kernel config -- CONFIG_NR_CPUS=32?

[Andrew Reid <reidac@bellatlantic.net>]

  Hi all --

  I recently deployed some new many-core servers at work, with
48 cores each (4x 12 core AMD 6174s), and ran into an issue where
the stock Debian kernel is compiled with CONFIG_NR_CPUS=32,
meaning it will only use the first 32 cores that it sees.

  For old Debian hands like me, this is an easy fix, I just built 
a new kernel configured for more cores, and it works just fine.

  But I'm curious if anyone on the list knows the rationale for
distributing kernels with this set to 32.  Is that just a 
reasonable number that's never been updated?  Or is there some
complication that arises after 32 cores, and should I be more
careful about tuning other parameters?

  I googled around a bit, but didn't find much...

				-- A.
-- 
Andrew Reid / reidac@bellatlantic.net