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