Beowulf & FFT

[dek_ml at konerding.com]

Martin Siegert writes:
>On Tue, 18 Jul 2000, Walter B. Ligon III wrote:
>
>> > Since I'm in the process of expanding the beowulf, I'm wondering whether
>> > switching to 133 MHz would improve the results (given that I can find
>> > a motherboard that supports ECC - we had that discussion).
>> 
>> Generally, if the problem is that node-to-node communication is too slow,
>> upping your system bus speed isn't going to do much in the way of improving
>> your parallel system performance.
>
>True. However, I'm not completely convinced that node-to-node communication
>is the only limiting factor: The efficiency for np=2 is miserable as well.
>And that should be shared-memory communication (at least in mpich-1.2.0).

My experience is that MPICH and LAM give very poor performance on linux with
100BT.  Why don't you try MPI/PRO?  It's easy to download and install, and it works
well (I went from 4X scaling on 10CPUs to 8X scaling on a communications-intensive
code).

Dave