81 строка
2.5 KiB
C
81 строка
2.5 KiB
C
#define _GNU_SOURCE
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#include <stdio.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <mpi.h>
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#define NUM_CHILDREN 5
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int main(int argc, char* argv[])
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{
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int msg;
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MPI_Comm parent, children[NUM_CHILDREN];
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int rank, size, i;
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char hostname[512];
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pid_t pid;
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char *child_argv[2] = { "", NULL };
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MPI_Init(NULL, NULL);
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MPI_Comm_rank(MPI_COMM_WORLD, &rank);
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MPI_Comm_size(MPI_COMM_WORLD, &size);
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MPI_Comm_get_parent(&parent);
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/* If we get COMM_NULL back, then we're the parent */
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if (MPI_COMM_NULL == parent) {
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pid = getpid();
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/* First, spawn all the children. Give them an argv
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identifying which child they are */
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for (i = 0; i < NUM_CHILDREN; ++i) {
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printf("Parent [pid %ld] about to spawn child #%d\n",
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(long)pid, i);
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asprintf(&(child_argv[0]), "%d", i);
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MPI_Comm_spawn(argv[0], child_argv, 1, MPI_INFO_NULL,
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0, MPI_COMM_WORLD, &children[i],
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MPI_ERRCODES_IGNORE);
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printf("Parent done with spawn of child %d\n", i);
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}
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/* Now send each of the children a message */
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if (0 == rank) {
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for (i = 0; i < NUM_CHILDREN; ++i) {
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printf("Parent sending message to child %d\n", i);
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MPI_Send(&i, 1, MPI_INT, 0, 1, children[i]);
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}
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}
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/* Now disconnect from each of the children */
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for (i = 0; i < NUM_CHILDREN; ++i) {
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printf("Parent disconnecting from child %d\n", i);
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MPI_Comm_disconnect(&children[i]);
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printf("Parent disconnected from child %d\n", i);
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}
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}
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/* Otherwise, we're the child */
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else {
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gethostname(hostname, 512);
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if (argc == 1) {
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printf("ERROR: child did not receive exepcted argv!\n");
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i = -1;
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} else {
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i = atoi(argv[1]);
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}
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pid = getpid();
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printf("Hello from the child %d on host %s pid %ld\n", i, hostname, (long)pid);
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if (0 == rank) {
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MPI_Recv(&msg, 1, MPI_INT, 0, 1, parent, MPI_STATUS_IGNORE);
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printf("Child %d received msg: %d\n", i, msg);
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if (i != msg) {
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printf("ERROR: Child %d got wrong message (got %d, expected %d)\n",
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i, msg, i);
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}
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}
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MPI_Comm_disconnect(&parent);
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printf("Child %d disconnected\n", i);
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}
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MPI_Finalize();
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return 0;
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}
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