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Subject: Re: [OMPI users] How to test it
From: Gus Correa (gus_at_[hidden])
Date: 2010-01-05 17:38:49


Hi Leonardo

It depends on how many "slots" (a.k.a. CPUs/cores) you have per node.

You can add the flag "-bynode" to the mpiexec command line
to force it to run on different nodes.

"man mpiexec" is a helpful source of information about these things.

I hope this helps.
Gus Correa
---------------------------------------------------------------------
Gustavo Correa
Lamont-Doherty Earth Observatory - Columbia University
Palisades, NY, 10964-8000 - USA
---------------------------------------------------------------------

Leonardo Machado Moreira wrote:
> Sorry If I misunderstood but, Should the mpirun -np4 hostname command
> return all the machines no the openmpi-default-hostfile?
>
> My host file has just two ips, the first is the server and the second a
> node.
>
> 192.168.0.1
> 192.168.0.3
>
> It just return the name of my server 4 times.
>
> The same happens with other commands like "ls" or just "dir".
>
> I didn't understood yet why does the mpi run the process 4 times or x
> times. It must be just one but spreading it on the other machines. Must
> not it??
>
>
>
>
>
> On Tue, Jan 5, 2010 at 6:14 PM, Jeff Squyres <jsquyres_at_[hidden]
> <mailto:jsquyres_at_[hidden]>> wrote:
>
> You might want to try something simpler than java to start with.
> For example:
>
> mpirun -np 4 hostname
>
> (where hostname is the POSIX command line app, not an MPI app)
>
> You should see the hostnames from the first 4 hosts in your hostfile
> (assuming each one of them has 1 process slot). Then try running
> the samples that are in the examples/ directory in the Open MPI
> tarball (make sure that the example executables are available in the
> same location on every node). For example:
>
> cd examples
> make
> mpirun -np 4 hello_c
>
> That's a trivial C MPI application that is the MPI equivalent of
> "hello world".
>
>
> On Jan 5, 2010, at 11:18 AM, Leonardo Machado Moreira wrote:
>
> > Hi, I have created a cluster with openmpi this way.
> >
> > 1 - Configured SSH with authorized_keys from the server to the nodes.
> > 2 - In /etc/openmpi-default-hostfile\ I have typed the IP of
> every nodes and the server.
> > 3 - Afterward I have created a Java application of two threads
> just to type a text on the console and runned it by
> > mpirun -1 java javaprogram
> > or
> > mpirun -2 java javaprogram
> > It is on the ps -aux of the server but the nodes are still stoped.
> >
> > How can I know that my mpi is working
> >
> > Thanks a lot
> > _______________________________________________
> > users mailing list
> > users_at_[hidden] <mailto:users_at_[hidden]>
> > http://www.open-mpi.org/mailman/listinfo.cgi/users
>
>
> --
> Jeff Squyres
> jsquyres_at_[hidden] <mailto:jsquyres_at_[hidden]>
>
>
> _______________________________________________
> users mailing list
> users_at_[hidden] <mailto:users_at_[hidden]>
> http://www.open-mpi.org/mailman/listinfo.cgi/users
>
>
>
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