All,
I'm trying to get the OpenMP portion of the code below to run
multicore on a couple of 8 core nodes.
Good news: multiple threads are being spawned on each node in the run.
Bad news: each of the threads only runs on a single core, leaving 7
cores basically idle.
Sorta good news: if I provide a rank file I get the threads running on
different cores within each node (PITA.
Here's the first lines of output.
/usr/mpi/gcc/openmpi-1.4-qlc/bin/mpirun -host c005,c006 -np 2 -rf
rank.file -x OMP_NUM_THREADS=4 hybrid4.gcc
Hello from thread 2 out of 4 from process 1 out of 2 on c006.local
another parallel region: name:c006.local MPI_RANK_ID=1 OMP_THREAD_ID=2
Hello from thread 3 out of 4 from process 1 out of 2 on c006.local
another parallel region: name:c006.local MPI_RANK_ID=1 OMP_THREAD_ID=3
Hello from thread 1 out of 4 from process 1 out of 2 on c006.local
another parallel region: name:c006.local MPI_RANK_ID=1 OMP_THREAD_ID=1
Hello from thread 1 out of 4 from process 0 out of 2 on c005.local
another parallel region: name:c005.local MPI_RANK_ID=0 OMP_THREAD_ID=1
Hello from thread 3 out of 4 from process 0 out of 2 on c005.local
Hello from thread 2 out of 4 from process 0 out of 2 on c005.local
another parallel region: name:c005.local MPI_RANK_ID=0 OMP_THREAD_ID=3
another parallel region: name:c005.local MPI_RANK_ID=0 OMP_THREAD_ID=2
Hello from thread 0 out of 4 from process 0 out of 2 on c005.local
another parallel region: name:c005.local MPI_RANK_ID=0 OMP_THREAD_ID=0
Hello from thread 0 out of 4 from process 1 out of 2 on c006.local
another parallel region: name:c006.local MPI_RANK_ID=1 OMP_THREAD_ID=0
another parallel region: name:c005.local MPI_RANK_ID=0 OMP_THREAD_ID=3
another parallel region: name:c005.local MPI_RANK_ID=0 OMP_THREAD_ID=2
another parallel region: name:c005.local MPI_RANK_ID=0 OMP_THREAD_ID=0
another parallel region: name:c006.local MPI_RANK_ID=1 OMP_THREAD_ID=3
another parallel region: name:c005.local MPI_RANK_ID=0 OMP_THREAD_ID=3
another parallel region: name:c005.local MPI_RANK_ID=0 OMP_THREAD_ID=2
another parallel region: name:c006.local MPI_RANK_ID=1 OMP_THREAD_ID=0
another parallel region: name:c006.local MPI_RANK_ID=1 OMP_THREAD_ID=1
.
.
.
Here's the simple code:
#include <stdio.h>
#include "mpi.h"
#include <omp.h>
int main(int argc, char *argv[]) {
int numprocs, rank, namelen;
char processor_name[MPI_MAX_PROCESSOR_NAME];
int iam = 0, np = 1;
char name[MPI_MAX_PROCESSOR_NAME]; /* MPI_MAX_PROCESSOR_NAME ==
128 */
int O_ID; /* OpenMP thread ID
*/
int M_ID; /* MPI rank ID
*/
int rtn_val;
MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Get_processor_name(processor_name, &namelen);
#pragma omp parallel default(shared) private(iam, np,O_ID)
{
np = omp_get_num_threads();
iam = omp_get_thread_num();
printf("Hello from thread %d out of %d from process %d out of %d on %s\n",
iam, np, rank, numprocs, processor_name);
int i=0;
int j=0;
double counter=0;
for(i =0;i<99999999;i++)
{
O_ID = omp_get_thread_num(); /* get OpenMP
thread ID */
MPI_Get_processor_name(name,&namelen);
rtn_val = MPI_Comm_rank(MPI_COMM_WORLD,&M_ID);
printf("another parallel region: name:%s
MPI_RANK_ID=%d OMP_THREAD_ID=%d\n", name,M_ID,O_ID);
for(j = 0;j<999999999;j++)
{
counter=counter+i;
}
}
}
MPI_Finalize();
}
