Beowulfs can compete with Supercomputers [was Beowulf: A theo rical approach]

[Bill Rankin]

Hey Greg,


> Many supercomputer sites use IBM SP machines, which are 
> clusters, so there
> isn't that much to prove. 

One question: from what I remember the nodes within an SP
are moderate sized SMP in their own right.  Mixed mode programming
(threads within a node, MPI between nodes) was becoming popular 
as a way of increasing scalability (or rather avoiding the 
imediate penalties).  I seem to remember Pete Beckman and Co. talking
about this at the SIAM PP/GS conference a couple years back.

Have you guys had any experience with comparing the performance of
similar codes on an SP versus a fully distributed cluster with similar
performance and number of processors?  

Also, speaking of weather prediction, des anyone know of any recent
advances in getting the shallow-water model to perform well on
a cluster?  I was always under the impression that this was a big
sticking point for some of the more complex models.

Thanks,

-bill