[Beowulf] bandwidth: who needs it?

Mark Hahn hahn at physics.mcmaster.ca
Sat Oct 16 14:36:01 PDT 2004


do you have applications that are pushing the limits of MPI bandwidth?
for instance, code that actually comes close to using the 8-900 MB/s
that current high-end interconnect provides?

we have a fairly wide variety of codes inside SHARCnet, but I haven't
found anyone who is even complaining about our last-generation fabric
(quadrics elan3, around 250 MB/s).  is it just that we don't have the 
right researchers?  I've heard people mutter about earthquake researchers
being able to pin a 800 MB/s network, and claims that big FFT folk can
do so as well.  by contrast, many people claim to notice improvements
in latency from old/mundane (6-7 us) to new/good (<2 us).

I'd be interested in hearing about applications you know of which are 
very sensitive to having large bandwidth (say, .8 GB/s today).

thanks, mark hahn.




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