[Beowulf] Cheap SDR IB

[Brian Oborn]

> With more cores on a single node, the IB benefits are seen in much lower number of nodes. I am testing some applications on a new cluster that I have (dual sockets quad core Barcelona), and my first results are with Fluent new benchmarks. I will have the numbers posted soon, so you all can take a look. For 2 nodes, IB shows an average of 15-20% higher performance then GigE, and this gap gets bigger with cluster size.
A quick side question. Is it possible to use IB as a cross-over with no 
switch? If I had just 2 fat nodes could I connect the HCAs directly to 
each other and avoid the switch costs? Could this be extended to ring or 
hypercube topologies?

Thanks,

Brian Oborn