[Beowulf] Help with inconsistent network performance

[Jon Forrest]

Brendan Moloney wrote:
> Since it is a full duplex switched network, there should not be any 
> collisions happening. 

I have a similar situation with a slightly larger cluster.
At first I also thought it was a network performance
problem. But then I ran the iftop program to watch
the network in realtime and I saw that I wasn't
even close to sending enough data to tax the switch.

I still don't know the cause of the problem but
I'm pretty sure it's not cause by excessive
network traffic. I suggest you try iftop to
see what your program is really doing.

Cordially,
-- 
Jon Forrest
Unix Computing Support
College of Chemistry
173 Tan Hall
University of California Berkeley
Berkeley, CA
94720-1460
510-643-1032
jlforrest at berkeley.edu