[Beowulf] myrinet (scali) or ethernet

[Joachim Worringen]

Patricia wrote:
> Hi People,
> 
> I am user of two clusters: One runs under myrinet and
> the other under scali. In both cases I installed my
> software to run under each of them (but not ethernet).
> All I want to know is how to check whether my parallel
> jobs are indeed running under myrinet (scali) or
> ethernet. 

For Myrinet, you can check if an MPI-programm linked against the 
MPICH-GM library runs correctly.

With Scali ("MPI Connect"), it's more complicated as it can fallback to 
Ethernet if the other interconnect (SCI?) does not work. Just run a 
ping-pong benchmark to measure latency (there's one included with Scali 
MPI), and if you get < 10us latency, you are not using Ethernet. Next to 
this, there should also be diagnostic tools included.

  Joachim

-- 
Joachim Worringen - NEC C&C research lab St.Augustin
fon +49-2241-9252.20 - fax .99 - http://www.ccrl-nece.de