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

Jayesh Krishna jayesh at mcs.anl.gov
Wed Jun 30 15:51:13 CDT 2010


Hi,
 Which version of MPICH2 are you using ?
 Do the two machines have the same underlying architecture (MPICH2 currently does not support heterogeneous systems - So you cannot run your job across 32-bit and 64-bit machines/MPICH2_libs)?
 Also try checking the control panel to see if the MPI processes are being launched on the machines.

Regards,
Jayesh 

----- Original Message -----
From: "David Lowinger" <David_Lowinger at ea.epson.com>
To: mpich-discuss at mcs.anl.gov
Sent: Wednesday, June 30, 2010 3:42:22 PM GMT -06:00 US/Canada Central
Subject: Re: [mpich-discuss] command line ordering of hosts matters?



Firewall is turned off on both machines. 
There is no error message... the MPI_Bcase simply never completes. I've left it running for 10 minutes, and the second printf ("completed MPI_Bcast") never appears when I use the second host ordering below ("10.0.0.101 1 10.0.0.6 1"). 
When I run "smpd -status 10.0.0.6" from 10.0.0.101, I see the message "smpd running on 10.0.0.6". When I run "smpd -status 10.0.0.101" from 10.0.0.6, I see the message "smpd running on 10.0.0.101". 



	jayesh at mcs.anl.gov 

06/30/2010 10:50 AM 
Expire Date: 06/29/2012 
		
To 	mpich-discuss at mcs.anl.gov 
	
cc 	David_Lowinger at ea.epson.com 
	
Subject 	Re: [mpich-discuss] command line ordering of hosts matters? 
		



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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