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Subject: Re: [OMPI users] iof, readline, lost stdin buffering
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2008-04-02 20:34:48

On Apr 1, 2008, at 2:36 PM, Will Portnoy wrote:
> I am using MPI in a somewhat nontraditional fashion. My program calls
> MPI_Comm_Spawn to start worker processes that are driven by my
> shell-like program. My program uses readline for input, and is *not*
> started by mpirun.

Do you mean that you are starting it via ./my_mpi_program?

> I have a problem where if I paste large amounts of text to my program
> in my terminal, much of it is lost (where large is still less than
> 1K). Without MPI, this normal input buffering worked, and the program
> processed the buffered input as it finished processing earlier input.

Uck. :-(

What happens if you replace readline with a simple fgets() (or
equivalent)? That is, I'm curious to see if the problem is with
OMPI's interaction with readline or our I/O forwarding in general.

> I understand that the i/o forwarding system may not interact well with
> the readline library, and I'm guessing this may the cause. (It's
> probably not relevant, but I'm using putty as a ssh client to reach
> the linux machine).
> Is this likely? I can try to put together a reproduction case, though
> it will require quite a bit of work.
> Is it possible to disable the iof system? I only need stdin, stdout,
> stderr from my non-mpirun-started program and none of the worker
> processes.

No, it is not possible to disable iof.

> Any other suggestions?
> thank you,
> Will
> _______________________________________________
> users mailing list
> users_at_[hidden]

Jeff Squyres
Cisco Systems