[mpich-discuss] command line ordering of hosts matters?

[jayesh at mcs.anl.gov]

Hi,
 Do you have a firewall running on any of these machines (If so, can you try running your job after turning off the firewall)?
 What is the error message that you get when you run your job ?
 Can you try running "smpd -status REMOTE_MACHINE" from each of the machines and let us know the results ("smpd -status 10.0.0.6" from 10.0.0.101 & "smpd -status 10.0.0.101" from 10.0.0.6)?

Regards,
Jayesh
----- Original Message -----
From: "David Lowinger" <David_Lowinger at ea.epson.com>
To: mpich-discuss at mcs.anl.gov
Sent: Tuesday, June 29, 2010 5:53:07 PM GMT -06:00 US/Canada Central
Subject: [mpich-discuss] command line ordering of hosts matters?



Hi, 
When running a very basic "hello world" app, I've found that the app's behavior depends on the order I use for hosts in the command line. For example, if I use: 

mpiexec -hosts 2 10.0.0.6 1 10.0.0.101 1 helloworld.exe 

The program executes flawlessly. But, if I use: 

mpiexec -hosts 2 10.0.0.101 1 10.0.0.6 1 helloworld.exe 

then the program never gets past the call to "MPI_Bcast()". Here is my code: 

------------------- 

#include "mpi.h" 

#define MPI_FLUSH() fflush(stdout) 

int main( int argc, char* argv[] ) 
{ 
int g_Thread_ID, g_Num_Threads; 
int test = 0; 

/**************************************************\ 
* MPI Initialization * 
\**************************************************/ 
MPI_Init(&argc, &argv); 
MPI_Comm_rank(MPI_COMM_WORLD, &g_Thread_ID); 
MPI_Comm_size(MPI_COMM_WORLD, &g_Num_Threads); 

printf("thread %d: main: About to execute MPI_Bcast\n", g_Thread_ID); 
MPI_FLUSH(); 

// Broadcast integer 
int err = MPI_Bcast(&test, 1, MPI_INT, 0, MPI_COMM_WORLD); 

printf("thread %d: completed MPI_Bcast\n", g_Thread_ID); 
MPI_FLUSH(); 

MPI_Finalize(); 
} 

------------------ 

I am running Windows Vista on both machines. Has anyone seen this before? Thanks, 
David 

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