+/* A simple example pingpong pogram to test MPI_Send and MPI_Recv */
+
+/* Copyright (c) 2009, 2010. The SimGrid Team.
+ * All rights reserved. */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <mpi.h>
+
+int main(int argc, char *argv[])
+{
+ int rank;
+ int size;
+ MPI_Status status;
+
+ int n = 0, m = 0, bytes = 0, workusecs = 0;
+ int currusecs;
+
+ char *buf = NULL;
+ int i, j;
+ struct timeval start_time, stop_time;
+ struct timeval start_pause, curr_pause;
+ unsigned long usecs;
+
+ MPI_Init(&argc, &argv); /* Initialize MPI */
+ MPI_Comm_size(MPI_COMM_WORLD, &size); /* Get nr of tasks */
+ MPI_Comm_rank(MPI_COMM_WORLD, &rank); /* Get id of this process */
+
+ if (size != 2) {
+ printf("run this program with exactly 2 processes (-np 2)\n");
+ MPI_Finalize();
+ exit(0);
+ }
+
+ if (0 == rank) {
+ if (argc > 1 && isdigit(argv[1][0])) {
+ n = atoi(argv[1]);
+ }
+ if (argc > 2 && isdigit(argv[2][0])) {
+ m = atoi(argv[2]);
+ }
+ if (argc > 3 && isdigit(argv[3][0])) {
+ bytes = atoi(argv[3]);
+ }
+ if (argc > 4 && isdigit(argv[4][0])) {
+ workusecs = atoi(argv[4]);
+ }
+ buf = malloc(sizeof(char) * bytes);
+ for (i = 0; i < bytes; i++) buf[i] = i % 256;
+ MPI_Send(&n, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
+ MPI_Send(&m, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
+ MPI_Send(&bytes, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
+ MPI_Send(&workusecs, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
+ MPI_Barrier(MPI_COMM_WORLD);
+ gettimeofday(&start_time, NULL);
+ for (i = 0; i < n; i++) {
+ for (j = 0; j < m; j++) {
+ MPI_Send(buf, bytes, MPI_CHAR, 1, 0, MPI_COMM_WORLD);
+ gettimeofday(&start_pause, NULL);
+ currusecs = 0;
+ while (currusecs < workusecs) {
+ gettimeofday(&curr_pause, NULL);
+ currusecs = (curr_pause.tv_sec - start_pause.tv_sec) * 1e6 + curr_pause.tv_usec - start_pause.tv_usec;
+ }
+ }
+ MPI_Recv(buf, bytes, MPI_CHAR, 1, 0, MPI_COMM_WORLD, &status);
+ }
+ gettimeofday(&stop_time, NULL);
+ usecs = (stop_time.tv_sec - start_time.tv_sec) * 1e6 + stop_time.tv_usec - start_time.tv_usec;
+ printf("n: %d m: %d bytes: %d sleep: %d usecs: %u\n", n, m, bytes, workusecs, usecs);
+ } else {
+ MPI_Recv(&n, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, &status);
+ MPI_Recv(&m, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, &status);
+ MPI_Recv(&bytes, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, &status);
+ MPI_Recv(&workusecs, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, &status);
+ buf = malloc(sizeof(char) * bytes);
+ MPI_Barrier(MPI_COMM_WORLD);
+ for (i = 0; i < n; i++) {
+ for (j = 0; j < m; j++) {
+ MPI_Recv(buf, bytes, MPI_CHAR, 0, 0, MPI_COMM_WORLD, &status);
+ }
+ MPI_Send(buf, bytes, MPI_CHAR, 0, 0, MPI_COMM_WORLD);
+ }
+ }
+ free(buf);
+ MPI_Finalize();
+ return 0;
+}