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Subject: Re: [OMPI users] Displaying Selected MCA Modules
From: Joshua Bernstein (jbernstein_at_[hidden])
Date: 2008-06-23 16:12:41

Ralph Castain wrote:
> Hi Joshua
> Again, forwarded by the friendly elf - so include me directly in any reply.
> I gather from Jeff that you are attempting to do something with bproc -
> true? If so, I will echo what Jeff said: bproc support in OMPI is being
> dropped with the 1.3 release due to lack of interest/support. Just a "heads
> up".


> If you are operating in a bproc environment, then I'm not sure why you are
> specifying that the system use the rsh launcher. Bproc requires some very
> special handling which is only present in the bproc launcher. You can run
> both MPI and non-MPI apps with it, but bproc is weird and so OMPI some
> -very- different logic in it to make it all work.

Well, I'm trying to determine how broken, if at all, the bproc support
is in OpenMPI. So considering out of the gate it wasn't working, I
thought I'd try to disable the built in BProc stuff and fall back to RSH.

> I suspect the problem you are having is that all of the frameworks are
> detecting bproc and trying to run accordingly. This means that the orted is
> executing process startup procedures for bproc - which are totally different
> than for any other environment (e.g., rsh). If mpirun is attempting to
> execute an rsh launch, and the orted is expecting a bproc launch, then I can
> guarantee that no processes will be launched and you will hang.

Exactly, what I'm seeing now...

> I'm not sure there is a way in 1.2 to tell the orteds to ignore the fact
> that they see bproc and do something else. I can look, but would rather wait
> to hear if that is truly what you are trying to do, and why.

I would really appreciate it if you wouldn't mind looking. From reading
the documentation I didn't realize that mpirun and the orted were doing
two different things. I thought the --mca parameter applied to both.

-Joshua Bernstein
Software Engineer
Penguin Computing