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Subject: Re: [OMPI users] Xgrid and choosing agents...
From: Luis Vitorio Cargnini (lvcargnini_at_[hidden])
Date: 2009-07-11 14:48:55


So you have 4 nodes each one with 2 processors, each processor 4-core
- quad-core.
So you have capacity for 32 process in parallel.
I think that only using the hostfile is enough is how I use. If you to
specify a specific host or a different sequence, the mpirun will obey
the host sequence in your hostfile to start the process, also can you
put how you configured your host files ? I'm asking this because you
should have something like:
# This is an example hostfile. Comments begin with
# #
# The following node is a single processor machine:
  # The following node is a dual-processor machine: slots=2
# The following node is a quad-processor machine, and we absolutely
# want to disallow over-subscribing it: slots=4 max-slots=4
so in your case like mine you should have something like:
your.hostname.domain slots=8 max-slots=8 # for each node

I hope this will help you.

Le 09-07-11 à 10:56, Klymak Jody a écrit :

> Hi all,
> Sorry in advance if these are naive questions - I'm not experienced
> in running a grid...
> I'm using openMPI on 4 duo Quad-core Xeon xserves. The 8 cores
> mimic 16 cores and show up in xgrid as each agent having 16
> processors. However, the processing speed goes down as the used
> processors exceeds 8, so if possible I'd prefer to not have more
> than 8 processors working on each machine at a time.
> Unfortunately, if I submit a 16-processor job to xgrid it all goes
> to "xserve03". Or even worse, it does so if I submit two separate 8-
> processor jobs. Is there anyway to steer jobs to less-busy agents?
> I tried making a hostfile and then specifying the host, but I get:
> /usr/local/openmpi/bin/mpirun -n 8 --hostfile hostfile --host
> xserve01.local ../build/mitgcmuv
> Some of the requested hosts are not included in the current
> allocation for the
> application:
> ../build/mitgcmuv
> The requested hosts were:
> xserve01.local
> so I assume --host doesn't work with xgrid?
> Is a reasonable alternative to simply not use xgrid and rely on ssh?
> Thanks, Jody
> --
> Jody Klymak
> _______________________________________________
> users mailing list
> users_at_[hidden]

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