[Beowulf] Network considerations for new generation cheap beowulfcluster

[Peter St. John]

But oh and Jim if you recall any papers about this I could read that would
be "Jim" Dandy.
Peter


On 5/23/07, Jim Lux <James.P.Lux at jpl.nasa.gov> wrote:
>
> At 09:19 AM 5/22/2007, Peter St. John wrote:
>
> A hypercube ( http://en.wikipedia.org/wiki/Hypercube) also gets you
> exponential space; the max hops is the dimension (3 for a 3-dimensional
> cube) and the number of nodes is exp(base 2) of the dimension (8 vertices on
> a cube). To do a tesseract (4-cube), which looks like two cubes nested,
> you'd need 4 ports per node, 16 nodes, 32 cables, max hop 4. I've poked
> around and don't see a great 4 ports per node solution; I like the
> suggestion of putting a router on a motherboard.
>
>
> Mind you, this is what Intel started with on their iPSC/1 and iPSC/2
> computers.  The early ones had multiple NICs in the nodes, then, later, they
> had a 8 port (I think) router in each node.
>
> It's not clear that this saves anything over a simpler architecture (e.g.
> external switch with lots of ports in a crossbar) unless you can do circuit
> switched routing (so you don't have a one packet delay in the switch) AND
> your algorithm can take advantage of it. I spent quite some time in the late
> 80s trying to figure out clever ways to take advantage of a hypercube
> topology for a modeling application..  I'm sure there are algorithms which
> are a natural fit, but the ones I was using weren't.
>
>
> James Lux, P.E.
> Spacecraft Radio Frequency Subsystems Group
> Flight Communications Systems Section
> Jet Propulsion Laboratory, Mail Stop 161-213
> 4800 Oak Grove Drive
> Pasadena CA 91109
> tel: (818)354-2075
> fax: (818)393-6875
>
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