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Subject: Re: [OMPI users] Busy waiting [was Re: (no subject)]
From: Adrian Knoth (adi_at_[hidden])
Date: 2008-04-24 09:09:12


On Thu, Apr 24, 2008 at 08:25:44AM -0400, Alberto Giannetti wrote:

> > I am using one of the nodes as a desktop computer. Therefore it is
> > most important for me that the mpi program is not so greedily
> > acquiring cpu time.

> From a performance/usability stand, you could set interactive
> applications on higher priority to guarantee your desktop
> applications work as expected.

What you really mean is to renice the MPI program to 10 or even 19.

It's usually not a good idea to raise the priority of any program below
0, as this could lock up your machine (that's why nice-levels below 0
are reserved for privileged users (root))

(note that lower nice levels actually mean higher priority. Just to
avoid confusion. I guess I don't have to mention "man nice" on a
technical mailing list.)

Anyway, I suggest you set mpi_yield_when_idle=1 in your mca-params.conf.

-- 
Cluster and Metacomputing Working Group
Friedrich-Schiller-Universität Jena, Germany
private: http://adi.thur.de