[Beowulf] Network considerations for new generation cheap beowulfcluster

[Jim Lux]

At 10:52 AM 5/23/2007, Peter St. John wrote:
>But oh and Jim if you recall any papers about this I could read that 
>would be "Jim" Dandy.

I was working off memory, and the iPSC/1 and iPSC/2 manuals I have in 
my office as a historical artifact.

I seem to recall that if you google hypercube and intel, you'll turn 
up some of the papers that were written early on.  The guys who 
started with the hypercube interconnect were at CalTech, as I recall, 
and spun off to form a supercomputer company embodying that, which 
Intel also adopted.

>Peter
>
>
>On 5/23/07, Jim Lux 
><<mailto:James.P.Lux at jpl.nasa.gov>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
>

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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