[mpich-discuss] MPI_Comm_spawn_multiple() fails

[jayesh at mcs.anl.gov]

Hi,
 Couple of suggestions,

# Does it work if you use the same command (same program) for all instances of the spawned procs ?
# Did you try setting the "path" infos for the commands ?

 You can find some examples at https://svn.mcs.anl.gov/repos/mpi/mpich2/trunk/test/mpi/spawn (Look at spawnminfo1.c) . Let us know the results.

Regards,
Jayesh
----- Original Message -----
From: "Alex Bakkal" <Abakkal at LOANPERFORMANCE.com>
To: mpich-discuss at mcs.anl.gov
Sent: Thursday, April 1, 2010 4:58:07 PM GMT -06:00 US/Canada Central
Subject: [mpich-discuss] MPI_Comm_spawn_multiple() fails



Hello, 

I have installed MPICH2 v.1.2.1 on Windows XP Pro machines and was trying to run the following test app on "mt" channel: 



#define NHOST 2 

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

int supported; 

int rank, size; 

MPI_Comm parent, intercomm; 



MPI_Init_thread(&argc, &argv, MPI_THREAD_MULTIPLE, &supported); 

if (supported != MPI_THREAD_MULTIPLE){ 

printf( "The library does not support MPI_THREAD_MULTIPLE\n" ); 

exit(-1); 

} 

MPI_Comm_get_parent(&parent); 

if (parent == MPI_COMM_NULL){ 

int i; 

int nproc[NHOST] = {1 , 1 }; 

char * progs[NHOST] = { "c:\\mpi_spawn" , "c:\\tm\\mpi_spawn" }; 



MPI_Info infos[NHOST]; 



for (i=0; i < NHOST; i++) { 

MPI_Info_create(&infos[i]); 

MPI_Info_set(infos[i], "host" , "localhost" ); 

} 

MPI_Comm_spawn_multiple(NHOST, 

progs, MPI_ARGVS_NULL, nproc, infos, 

0, MPI_COMM_WORLD, &intercomm, MPI_ERRCODES_IGNORE); 

for (i=0; i < NHOST; i++) { 

MPI_Info_free(&infos[i]); 

} 

} 

else { 

intercomm = parent; 

} 

MPI_Comm_rank(intercomm, &rank); 

MPI_Comm_size(intercomm, &size); 

printf( "[%d/%d] Hello world\n" , rank, size); fflush(stdout); 

MPI_Comm_free(&intercomm); 

MPI_Finalize(); 

return 0; 

} 

The app hangs. I can see three (as expected) instances of the program in the Task Manager but MPI_Comm_spawn_multiple() never returns control to my app. 

I have reduced the number of spawned hosts to one and it ran successfully. Also, it spawned successfully two hosts with the following line commented out: 

//MPI_Info_set(infos[i], "host" , "localhost" ); 

I have tried it on two machines with the same result. 



Also, I have tried to spawn just one instance but on the remote host and got the following error messages: 

ERROR:unable to read the cmd header on the pmi context, Error = -1 

ERROR:Error posting ready, An existing connection was forcibly closed by the remote host. 

I am not sure whether that is related to the first issue? 



Any insight would be greately appreciated. 

Thank you. 

Alex 

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