[Beowulf] Cheap SDR IB
Shainer at mellanox.com
Wed Jan 30 15:20:43 PST 2008
> > Just in case you've missed the announcements:
> > http://www.clustermonkey.net//content/view/222/1/
> Interesting that Infiniband is getting down close to the
> predicted $100 per HCA price. Certainly $250 per node (HCA,
> cable, and switch) for 24 ports makes it easier to justify if
> the performance is there. So of course that begs the
> question, what is the performance?
> I noticed that the price is for the InfiniHost III Lx, does
> anyone know if the Ex (mentioned in the performance table)
> and Lx (mentioned in the price list) perform identically? Or
> any of the standard numbers for MPI latency and/or bandwidth
> for the Lx part?
> I googled around and found a few PDFs, but no real numbers.
> Some EE magazine mentioned 4us roughly, but it wasn't clear
> exactly what they were measuring.
Mellanox has 4 IB families - InfiniHost, InfiniHost III Lx, InfiniHost
III Ex and ConnectX. InfiniHost is a PCI-X device and the other 3 are
PCIe based. The Ex and LX support IB DDR and ConnectX supports IB QDR
and PCIe Gen2.
>From latency point of view, the LX is a 3.5-3.3us MPI latency (SDR/DDR),
the Ex is 2.6-2.3us (SDR/DDR) and ConnectX is 1.2-1us (PCIe Gen1/Gen2).
For BW, Lx provides ~1400MB/s, EX is ~1500MB/s and ConnectX is ~1900MB/s
uni-directional on PCIe Gen2.
Feel free to contact me directly for more info.
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