PCI-64: how to find

[Patrick Geoffray]

Hi David,

David Geldreich wrote:
>      I am currently having problem with fullduplex; the driver and my
> switch are telling fullduplex, but doing ttcp in both direction
> simultaneously gives only 520Mbit/s in both direction (a total of
> 1040Mbit were I expect 1800Mbit).

What is the load of your CPU(s) ? That may be the bottleneck in 
bidirectional.

>      Is there (objective) comparison chart (bandwidth + latency) of
> Gigabit ethernet vs Myrinet vs Dolphin ?

It's impossible to get an objective comparaison, there is too many 
variables (CPU, PCI, memory bus, sw interface, pattern, number of nodes, 
topology, etc).

Moreover, if you use IP, the performance on all interconnects will be 
limited by the CPU clock, if the link is fast enough.
You should look at the excellent Trapeze project at Duke 
http://www.cs.duke.edu/ari/trapeze/, and specially at Drew's slides:
http://www.cs.duke.edu/ari/trapeze/slides/freenix/index.htm to get the 
big picture.

Patrick

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