From: "Alain Coetmeur" <alain.coetmeur@icdc.caissedesdepots.fr>
Newsgroups: comp.parallel.mpi
Subject: Re: mpich-gdb and tv
Date: Thu, 20 May 1999 16:57:33 +0200
Organization: Informatique-CDC
Message-Id: <7i181v$22t1@puligny.idt.cdc.fr>
References: <374324E1.5D4ABEE8@ernie.icslab.agh.edu.pl>
Mime-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 8bit
Xref: ukc comp.parallel.mpi:5111


Radoslaw Gembarowski a écrit dans le message <374324E1.5D4ABEE8@ernie.icslab.agh.edu.pl>...
>I write a monitor( module of a debugger) for mpich and I intrested in a
>control of processes of MPI aplication. If I run program (n processes)
>with  options gdb or tv - (debug option) (mpirun -np <n> -gdb prog)
>mpich will create 2*n processes of a parallel program. Why?
which platform do you use ?

>Why does every process  of MPI program have  a duplicate? What use a
>duplicate processes?

this is a secret of the unix behind.

I suppose that you say rthis because the other process have the same name,
which is quite strange.

maybe does the program fork()
and one of the instance do some relaying, bookkeeping, or manage all
instead of running your program.

however it would be more logical that one of the 2 process is just
a "gdb" debugger instance connected to your program,
and communicating to the master debugger GUI