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Subject: Re: [OMPI users] Busy waiting [was Re: (no subject)]
From: Alberto Giannetti (albertogiannetti_at_[hidden])
Date: 2008-04-24 12:13:44


On Apr 24, 2008, at 9:09 AM, Adrian Knoth wrote:
> 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.

Linux has also a Posix real-time scheduling mode (priocntl).

>
> 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
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