[Beowulf] myrinet (scali) or ethernet
patrick at myri.com
Tue Oct 5 05:05:29 PDT 2004
> I am user of two clusters: One runs under myrinet and
> the other under scali. In both cases I installed my
Myrinet is hardware and Scali makes software. Do you run Scali's
software on Myrinet ?
> jobs are indeed running under myrinet (scali) or
Do you link with Scali's software or MPICH-GM ? If it's MPICH-GM,
binaries will only run on Myrinet. If it's Scali, I don't know, I guess
it chooses Myrinet or Ethernet at runtime. In this case, you can look at
the output of gm_board_info on a node where your job is running, and see
if any of the PIDs and the command lines of programs using a GM port
matches your application process. It may still be possible that Scali
opens a GM port without using it. Another solution would be to unplug a
few nodes but Scali may be able to use Ethernet only for the nodes where
Myrinet has been unplugged. You can also look at the GM counters (with
gm_counters) and see if the number of packets sent/received goes up.
However, you would not be sure if another process is using Myrinet at
that time or if IP/Myrinet is up and running too.
I guess there should be a way with Scali to know which device is used at
runtime, but I really don't know how.
Is it the same problem than the Myricom Help ticket #30885 ?
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