Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Open MPI User's mailing list

From: Brian Barrett (brbarret_at_[hidden])
Date: 2006-02-28 21:52:04


Jose -

I noticed that your output doesn't appear to match what the source
code is capable of generating. It's possible that you're running
into problems with the code that we can't see because you didn't send
a complete version of the source code.

You might want to start by running some 3rd party codes that are
known to be good, just to make sure that your MPI installation checks
out. A good start is NetPIPE, which runs between two peers and gives
latency / bandwidth information. If that runs, then it's time to
look at your application. If that doesn't run, then it's time to
look at the MPI installation in more detail. In this case, it would
be useful to see all of the information requested here:

   http://www.open-mpi.org/community/help/

as well as from running the mpirun command used to start NetPIPE with
the -d option, so something like:

   mpirun -np 2 -hostfile foo -d ./NPMpi

Brian

On Feb 28, 2006, at 9:29 AM, Jose Pedro Garcia Mahedero wrote:

> Hello everybody.
>
> I'm new to MPI and I'm having some problems while runnig a simple
> pingpong program in more than one node.
>
> 1.- I followed all the instructions and installed open MPI without
> problems in a Beowulf cluster.
> 2.- Ths cluster is working OK and ssh keys are set for not
> password prompting
> 3.- miexec seems to run OK.
> 4.- Now I'm using just 2 nodes: I've tried a simple ping-pong
> application but my master only sends one request!!
> 5.- I reduced the problem by trying to send just two mesages to the
> same node:
>
> int main(int argc, char **argv){
> int myrank;
>
> /* Initialize MPI */
>
> MPI_Init(&argc, &argv);
>
> /* Find out my identity in the default communicator */
>
> MPI_Comm_rank(MPI_COMM_WORLD, &myrank);
> if (myrank == 0) {
> int work = 100;
> int count=0;
> for (int i =0; i < 10; i++){
> cout << "MASTER IS SLEEPING..." << endl;
> sleep(3);
> cout << "MASTER AWAKE WILL SEND["<< count++ << "]:" << work
> << endl;
> MPI_Send(&work, 1, MPI_INT, 1, WORKTAG, MPI_COMM_WORLD);
> }
> } else {
> int count =0;
> int work;
> MPI_Status status;
> while (true){
> MPI_Recv(&work, 1, MPI_INT, 0, MPI_ANY_TAG,
> MPI_COMM_WORLD, &status);
> cout << "SLAVE[" << myrank << "] RECEIVED[" << count++ <<
> "]:" << work <<endl;
> if (status.MPI_TAG == DIETAG) {
> break;
> }
> }// while
> }
> MPI_Finalize();
>
>
>
> 6a.- RESULTS (if I put more than one machine in my mpihostsfile),
> my master sends the first message and my slave receives it
> perfectly. But my master doesnt send its second .
> message:
>
>
>
> Here's my output
>
> MASTER IS SLEEPING...
> MASTER AWAKE WILL SEND[0]:100
> MASTER IS SLEEPING...
> SLAVE[1] RECEIVED[0]:100MPI_STATUS.MPI_ERROR:0
> MASTER AWAKE WILL SEND[1]:100
>
> 6b.- RESULTS (if I put ONLY 1 machine in my mpihostsfile),
> everything is OK until iteration 9!!!
> MASTER IS SLEEPING...
> MASTER AWAKE WILL SEND[0]:100
> MASTER IS SLEEPING...
> MASTER AWAKE WILL SEND[1]:100
> MASTER IS SLEEPING...
> MASTER AWAKE WILL SEND[2]:100
> MASTER IS SLEEPING...
> MASTER AWAKE WILL SEND[3]:100
> MASTER IS SLEEPING...
> MASTER AWAKE WILL SEND[4]:100
> MASTER IS SLEEPING...
> MASTER AWAKE WILL SEND[5]:100
> MASTER IS SLEEPING...
> MASTER AWAKE WILL SEND[6]:100
> MASTER IS SLEEPING...
> MASTER AWAKE WILL SEND[7]:100
> MASTER IS SLEEPING...
> MASTER AWAKE WILL SEND[8]:100
> MASTER IS SLEEPING...
> MASTER AWAKE WILL SEND[9]:100
> SLAVE[1] RECEIVED[0]:100MPI_STATUS.MPI_ERROR:0
> SLAVE[1] RECEIVED[1]:100MPI_STATUS.MPI_ERROR:0
> SLAVE[1] RECEIVED[2]:100MPI_STATUS.MPI_ERROR:0
> SLAVE[1] RECEIVED[3]:100MPI_STATUS.MPI_ERROR:0
> SLAVE[1] RECEIVED[4]:100MPI_STATUS.MPI_ERROR:0
> SLAVE[1] RECEIVED[5]:100MPI_STATUS.MPI_ERROR:0
> SLAVE[1] RECEIVED[6]:100MPI_STATUS.MPI_ERROR:0
> SLAVE[1] RECEIVED[7]:100MPI_STATUS.MPI_ERROR:0
> SLAVE[1] RECEIVED[8]:100MPI_STATUS.MPI_ERROR:0
> SLAVE[1] RECEIVED[9]:100MPI_STATUS.MPI_ERROR:0
> --------------------------------
>
> I know this is a lot of text, but I wanted to give a mamixum
> detailed question. I've been search in FAQ, but still don't know
> what (and why) is going on...
>
> Anyone can help please :-) ?
>
> _______________________________________________
> users mailing list
> users_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/users

-- 
   Brian Barrett
   Open MPI developer
   http://www.open-mpi.org/