[xcpu] Re: (s)xcpu and MPI

[Latchesar Ionkov]

Hi,
Sorry for the late response, I was off on Friday. What version of  
mpich2 are you using? I tested only with mvapich2, so far.

Thanks,
        Lucho

On Oct 3, 2008, at 9:17 AM, Daniel Gruner wrote:


Further, if one specifies a single process then it works, but as soon
as more than one process starts the program hangs like I mentioned
before.

Daniel

On 10/3/08, Daniel Gruner <[EMAIL PROTECTED]> wrote:
Well, I just did the same, but with NO success...  The processes are
apparently started, run at the beginning, but then they hang and do
not finalize.  For example, running the "hellow" example from the
mvapich2 distribution:

[EMAIL PROTECTED] examples]# cat hellow.c
/* -*- Mode: C; c-basic-offset:4 ; -*- */
/*
 *  (C) 2001 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */

#include <stdio.h>
#include "mpi.h"

int main( int argc, char *argv[] )
{
   int rank;
   int size;

   MPI_Init( 0, 0 );
   MPI_Comm_rank(MPI_COMM_WORLD, &rank);
   MPI_Comm_size(MPI_COMM_WORLD, &size);
   printf( "Hello world from process %d of %d\n", rank, size );
   MPI_Finalize();
   return 0;
}

[EMAIL PROTECTED] examples]# make hellow
../bin/mpicc  -I../src/include -I../src/include   -c hellow.c
../bin/mpicc   -o hellow hellow.o
[EMAIL PROTECTED] examples]# ./hellow

Hello world from process 0 of 1


(this was fine, just running on the master).  Running on the two  
nodes
requires that the xmvapich process be killed (ctrl-C):

[EMAIL PROTECTED] examples]# xmvapich -ap ./hellow
n0000: Hello world from process 0 of 2
n0001: Hello world from process 1 of 2
[EMAIL PROTECTED] examples]#

I have tried other codes, both in C and Fortran, with the same
behaviour.  I don't know if the issue is with xmvapich or with
mvapich2.  Communication is just GigE.


Daniel



On 9/30/08, Abhishek Kulkarni <[EMAIL PROTECTED]> wrote:

Just gave this a quick try, and xmvapich seems to run MPI apps  
compiled
with mpich2 without any issues.

$ xmvapich -a ./mpihello
blender: Hello World from process 0 of 1
eregion: Hello World from process 0 of 1

Hope that helps,


 -- Abhishek


On Tue, 2008-09-30 at 17:02 +0200, Stefan Boresch wrote:
Thanks for the quick reply!

On Tue, Sep 30, 2008 at 07:34:37AM -0700, ron minnich wrote:

On Tue, Sep 30, 2008 at 1:57 AM, stefan  
<[EMAIL PROTECTED]> wrote:

the state of xcpu support with MPI libraries -- either of the  
common
free ones
is fine (e.g., openmpi, mpich2)


there is now support for mpich2. openmpi is not supported as  
openmpi
is (once again) in flux. it has been supported numerous times  
and has
changed out from under us numerous times. I no longer use  
openmpi if I
have a working mvapich or mpich available.


I am slightly confused. I guess I had inferred the openmpi issues  
from
the various mailing lists. But I just looked at the latest mpich2
prerelease and found no mentioning of (s)xcpu(2). I thought that  
some
patches/support on the side of the mpi library are necessary   
(as, e.g.,
openmpi provides for bproc ...)  Or am I completely  
misunderstanding
something here, and this is somehow handled by xcpu itself ...
I guess there is some difference between

xrx 192.168.19.2 /bin/date

and

xrx 192.168.19.2 <pathto>/mpiexec ...

and the latter seems too magic to me to run out of the box (it sure
would be nice though ...)

Sorry for making myself a nuisance -- thanks,

Stefan Boresch