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Subject: Re: [OMPI users] problems with hostfile when doing MPMD
From: Ralph Castain (rhc_at_[hidden])
Date: 2008-04-13 19:13:14


Hi Jody

Simple answer - the 1.2.x series does not support multiple hostfiles. I
believe you will find that documented in the FAQ section.

What you have to do here is have -one- hostfile that includes all the hosts,
and then -host each app-context to indicate which of those hosts are to be
used for that specific app-context.

Or you can just use -host for each app_context, with no hostfile specified.

If you specify a hostfile and -host, then -all- the nodes listed in your
-host's must be in the hostfile or we will error out.

This will change in 1.3 where we will support a separate hostfile for each
app_context, as well as one for the entire job, in combination with -host
args as well. You can see that documented on the open-mpi wiki.

Hope that helps
Ralph

On 4/10/08 4:40 AM, "jody" <jody.xha_at_[hidden]> wrote:

> HI
> In my network i have some 32 bit machines and some 64 bit machines.
> With --host i successfully call my application:
> mpirun -np 3 --host aim-plankton -x DISPLAY ./run_gdb.sh ./MPITest :
> -np 3 --host aim-fanta4 -x DISPLAY ./run_gdb.sh ./MPITest64
> (MPITest64 has the same code as MPITest, but was compiled on the 64
> bit machine)
>
> But when i use hostfiles:
> mpirun -np 3 --hostfile hosts32 -x DISPLAY ./run_gdb.sh ./MPITest :
> -np 3 --hostfile hosts64 -x DISPLAY ./run_gdb.sh ./MPITest64
> all 6 processes are started on the 64 bit machine aim-fanta4.
>
> hosts32:
> aim-plankton slots=3
> hosts64
> aim-fanta4 slots
>
> Is this a bug or a feature? ;)
>
> Jody
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