Testing MPI on Linux Mint Machines in FH

--D. Thiebaut (talk) 13:21, 15 May 2014 (EDT)

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MPI Hosts

This section is only visible to computers located at Smith College

Test #1: Run on Multi Cores of Same Host

• Login for FH345-02

cat > helloWorld.c
/* C Example */
#include <stdio.h>
#include <mpi.h>


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

 MPI_Init (&argc, &argv);      /* starts MPI */
 MPI_Comm_rank (MPI_COMM_WORLD, &rank);        /* get current process id */
 MPI_Comm_size (MPI_COMM_WORLD, &size);        /* get number of processes */
 printf( "Hello world from process %d of %d\n", rank, size );
 MPI_Finalize();
 return 0;
}

[13:14:50] ~/mpi$: mpicc -o hello2 helloWorld.c

[13:16:15] ~/mpi$: mpiexec -np 2 -host localhost  ./hello2 
Hello world from process 0 of 2
Hello world from process 1 of 2

Test on 3 Hosts

• Create hello.cpp program:

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

main(int argc, char **argv)
{
  int rank, size, tag, rc, i;
  MPI_Status status;
  char message[20];
  char processor_name[MPI_MAX_PROCESSOR_NAME];
  int name_len;

  rc = MPI_Init(&argc, &argv);
  rc = MPI_Comm_size(MPI_COMM_WORLD, &size);
  rc = MPI_Comm_rank(MPI_COMM_WORLD, &rank);

  // get processor name
  MPI_Get_processor_name(processor_name, &name_len);

  tag = 7;
  if (rank == 0) {
    strcpy(message, "Hello, world");
    for (i=1; i<size; i++)
      rc = MPI_Send(message, 13, MPI_CHAR, i, tag, MPI_COMM_WORLD);
  }
  else
    rc = MPI_Recv(message, 13, MPI_CHAR, 0, tag, MPI_COMM_WORLD, &status);
  printf( "node %d -- %s : %.13s\n", rank, processor_name, message);
  rc = MPI_Finalize();
}

• Compile it

mpic++ -o hello1 hello.cpp

• Generate new password-less entry

    ssh-keygen
    cp ~/.ssh/id_rsa.pub ~/.ssh/authorized_keys
    ls
    ls -l
    eval `ssh-agent -s`
    ssh-add
    ssh 131.229.101.176

• On all three machines, open ports 12000:12099

sudo -i
ufw allow proto tcp to any port 12000:12099
exit     # (back to normal user shell)
export MPICH_PORT_RANGE=12000:12099

• Try MPI program

mpiexec  -n 4 -f host_file ./hello1
stdin: is not a tty
stdin: is not a tty
node 1 -- ford345-07 : Hello, world
node 0 -- ford345-02 : Hello, world
node 3 -- ford345-02 : Hello, world
node 2 -- ford345-08 : Hello, world

It works!