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Subject: Re: [OMPI users] Scheduling dynamically spawned processes
From: Thatyene Louise Alves de Souza Ramos (thatyene_at_[hidden])
Date: 2011-05-16 14:19:56


Ralph,

I have the same issue and I've been searching how to do this, but I couldn't
find.

What exactly must be the string in the host info key to do what Rodrigo
described?

<<< Inside your master, you would create an MPI_Info key "host" that has a
value
<<< consisting of a string "host1,host2,host3" identifying the hosts you
want
<<< your slave to execute upon. Those hosts must have been included in
<<< my_hostfile. Include that key in the MPI_Info array passed to your
Spawn.

I tried to do what you said above but ompi ignores the repetition of hosts.
Using Rodrigo's example I did:

host info key = "m1,m2,m2,m2,m3" and number of processes = 5 and the result
was

m1 -> 2
m2 -> 2
m3 -> 1

and not

m1 -> 1
m2 -> 3
m3 -> 1

as I wanted.

Thanks in advance.

Thatyene Ramos

On Fri, May 13, 2011 at 9:16 PM, Ralph Castain <rhc_at_[hidden]> wrote:

> I believe I answered that question. You can use the hostfile info key, or
> you can use the host info key - either one will do what you require.
>
> On May 13, 2011, at 4:11 PM, Rodrigo Silva Oliveira wrote:
>
> Hi,
>
> I think I was not specific enough. I need to spawn the copies of a process
> in a unique mpi_spawn call. It is, I have to specify a list of machines and
> how many copies of the process will be spawned on each one. Is it possible?
>
> I would be something like that:
>
> machines #copies
> m1 1
> m2 3
> m3 1
>
> After an unique call to spawn, I want the copies running in this fashion. I
> tried use a hostfile with the option slot, but I'm not sure if it is the
> best way.
>
> hostfile:
>
> m1 slots=1
> m2 slots=3
> m3 slots=1
>
> Thanks
>
> --
> Rodrigo Silva Oliveira
> M.Sc. Student - Computer Science
> Universidade Federal de Minas Gerais
> www.dcc.ufmg.br/~rsilva <http://www.dcc.ufmg.br/%7Ersilva>
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