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Subject: Re: [OMPI users] Problems in OpenMPI
From: Ashley Pittman (ashley_at_[hidden])
Date: 2009-07-10 05:20:05


On Thu, 2009-07-09 at 23:40 -0500, Yin Feng wrote:
> I am a beginner in MPI.
>
> I ran an example code using OpenMPI and it seems work.
> And then I tried a parallel example in PETSc tutorials folder (ex5).
>
> mpirun -np 4 ex5
> It can do but the results are not as accurate as just running ex5.
> Is that thing normal?

Not as accurate or just different? Different is normal and in light of
that accurate is itself a vague concept.

> After that, send this job to supercomputer which allocates me 4 nodes
> and each node has 8 processors. When I check load on each node, I
> found:

> Does anyone have any idea about this?

I'd say it's obvious all 32 processes have been located on the same
node, what was the mpirun command you issued and the contents of the
machinefile you used?

Running "orte-ps" on the machine where the mpirun command is running
will tell you the hostname where every rank is running or if you want
more information (load, cpu usage etc) you can use padb, the link for
which is in my signature.

Ashley,

-- 
Ashley Pittman, Bath, UK.
Padb - A parallel job inspection tool for cluster computing
http://padb.pittman.org.uk