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Subject: Re: [OMPI users] RE : Bug when mixing sent types in version 1.6
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2012-06-08 12:22:37

On Jun 8, 2012, at 8:51 AM, BOUVIER Benjamin wrote:

> I have downloaded the Netpipe benchmarks suite, launched `make mpi` and launched with mpirun the resulting executable.
> Here is an interesting fact : by launching this executable on 2 nodes, it works ; on 3 nodes, it blocks, I guess on connect.

Netpipe is only intended for 2 processes -- I'm actually not sure offhand what happens if you run it with 3...

> Each process is running on a core, on each machine, using 100% of one CPU ; but nothing else happens. I have to kill the program to quit.

This is to be expected. OMPI polls aggressively for network progress (i.e., consumes 100% of a core).

> Setting the option -mca btl_base_verbose to 30 shows me that the last thing tried by each node is to connect to other nodes.

We don't output verbose messages for MPI traffic, so the lack of messages there doesn't mean anything.

I'd guess that running net pipe with 3 procs may be undefined.

Jeff Squyres
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