[Beowulf] 48-Core X86_64 Compute Node - Good Idea?

[Jon Forrest]

I have a cluster up and running that uses
those SuperMicro Twin boxes, which have
2 nodes per rack unit, with each node
using 2 AMD 6-core Istanbuls. This results
in 12 cores per node, or 24 cores per rack unit.
This is working fine.

Now that the 12-core AMD processors are out,
I was hoping that I could get the same configuration,
except using 12-core processors, and yielding
48 cores per rack unit. The problem is, as of
right now, I believe such boxes aren't available
yet. The closest thing is a 4-way 1U box, which
gives 48 cores per rack unit, but in *1 node*.

My intuition tells me that I should be wary of
such a configuration because of various SMP-related
locking and concurrency issues. There probably aren't
many single node 48 core boxes out there so there
might be surprises. I don't like surprises.

The obvious thing to do would be to wait until
the Twin boxes come out but my problem is that
I have money to spend that has to be spent soon,
maybe before the Twin boxes come out. So, I'm trying
to decide what to do. (I only want 1U boxes because
I have to pay for rack space).

Any advice?

Cordially,
-- 
Jon Forrest
Research Computing Support
College of Chemistry
173 Tan Hall
University of California Berkeley
Berkeley, CA
94720-1460
510-643-1032
jlforrest at berkeley.edu