#define ERROR_MARGIN 0.5
-static int verbose = 0;
-
-int main(int argc, char* argv[])
+int main(int argc, char *argv[])
{
- char *sbuf, *rbuf;
- int i, j;
- double t1, t2, t, ts;
- int rank, size;
- MPI_Status status;
+ char *sbuf, *rbuf;
+ int i, j;
+ double t1, t2, t, ts;
+ int rank, size;
+ MPI_Status status;
- MPI_Init(&argc,&argv);
- MPI_Comm_rank(MPI_COMM_WORLD,&rank);
- MPI_Comm_size(MPI_COMM_WORLD, &size);
+ MPI_Init(&argc, &argv);
+ MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+ MPI_Comm_size(MPI_COMM_WORLD, &size);
- if (getenv("MPITEST_VERBOSE")) verbose = 1;
+ /* Allocate memory regions to communicate */
+ sbuf = (char *) malloc(SIZE);
+ rbuf = (char *) malloc(size * SIZE);
- /* Allocate memory regions to communicate */
- sbuf = (char*) malloc(SIZE);
- rbuf = (char*) malloc(size * SIZE);
+ /* Touch the buffers to make sure they are allocated */
+ for (i = 0; i < SIZE; i++)
+ sbuf[i] = '0';
+ for (i = 0; i < SIZE * size; i++)
+ rbuf[i] = '0';
- /* Touch the buffers to make sure they are allocated */
- for (i = 0; i < SIZE; i++) sbuf[i] = '0';
- for (i = 0; i < SIZE * size; i++) rbuf[i] = '0';
+ /* Time when rank 0 gathers the data */
+ MPI_Barrier(MPI_COMM_WORLD);
+ t1 = MPI_Wtime();
+ for (i = 0; i < ITER; i++) {
+ MPI_Gather(sbuf, SIZE, MPI_BYTE, rbuf, SIZE, MPI_BYTE, 0, MPI_COMM_WORLD);
+ MPI_Barrier(MPI_COMM_WORLD);
+ }
+ t2 = MPI_Wtime();
+ t = (t2 - t1) / ITER;
- /* Time when rank 0 gathers the data */
- MPI_Barrier(MPI_COMM_WORLD);
- t1 = MPI_Wtime();
- for (i = 0; i < ITER; i++) {
- MPI_Gather(sbuf, SIZE, MPI_BYTE, rbuf, SIZE, MPI_BYTE, 0, MPI_COMM_WORLD);
- MPI_Barrier(MPI_COMM_WORLD);
- }
- t2 = MPI_Wtime();
- t = (t2-t1)/ITER;
+ /* Time when rank 1 gathers the data */
+ MPI_Barrier(MPI_COMM_WORLD);
+ t1 = MPI_Wtime();
+ for (j = 0; j < ITER; j++) {
+ MPI_Gather(sbuf, SIZE, MPI_BYTE, rbuf, SIZE, MPI_BYTE, 1, MPI_COMM_WORLD);
+ MPI_Barrier(MPI_COMM_WORLD);
+ }
+ t2 = MPI_Wtime();
+ ts = (t2 - t1) / ITER;
- /* Time when rank 1 gathers the data */
- MPI_Barrier(MPI_COMM_WORLD);
- t1 = MPI_Wtime();
- for (j = 0; j < ITER; j++) {
- MPI_Gather(sbuf, SIZE, MPI_BYTE, rbuf, SIZE, MPI_BYTE, 1, MPI_COMM_WORLD);
- MPI_Barrier(MPI_COMM_WORLD);
- }
- t2 = MPI_Wtime();
- ts = (t2-t1)/ITER;
+ if (rank == 1)
+ MPI_Send(&ts, 1, MPI_DOUBLE, 0, 0, MPI_COMM_WORLD);
+ if (rank == 0)
+ MPI_Recv(&ts, 1, MPI_DOUBLE, 1, 0, MPI_COMM_WORLD, &status);
- if (rank == 1)
- MPI_Send(&ts, 1, MPI_DOUBLE, 0, 0, MPI_COMM_WORLD);
- if (rank == 0)
- MPI_Recv(&ts, 1, MPI_DOUBLE, 1, 0, MPI_COMM_WORLD, &status);
+ /* Print out the results */
+ if (!rank) {
+ if ((ts / t) > (1 + ERROR_MARGIN)) { /* If the difference is more than 10%, it's an error */
+ printf("%.3f\t%.3f\n", 1000000.0 * ts, 1000000.0 * t);
+ printf("Too much difference in performance\n");
+ }
+ else
+ printf(" No Errors\n");
+ }
- /* Print out the results */
- if (!rank) {
- if ((ts / t) > (1 + ERROR_MARGIN)) { /* If the difference is more than 10%, it's an error */
- printf("%.3f\t%.3f\n", 1000000.0 * ts, 1000000.0 * t);
- printf("Too much difference in performance\n");
- }
- else printf(" No Errors\n");
- }
-
- MPI_Finalize();
free(sbuf);
free(rbuf);
- return 0;
+ MPI_Finalize();
+
+ return 0;
}
