[Beowulf] Cheap SDR IB

[Gilad Shainer]

> 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?

Gilad: Yes, for 2 nodes you don't need a switch, just connect the HCAs
directly. For more than 2 nodes, it is easier just to use a switch.



Thanks,

Brian Oborn