/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */

/*

 *  (C) 2006 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include <mpi.h>

#include "mpitest.h"

#include "mpithreadtest.h"

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#include <stdio.h>

#ifdef DO_DEBUG

#define DEBUG(_a){ _a ;fflush(stdout);}

#else

#define DEBUG(_a)

#endif

#define NUM_ITER 10000

const int REQ_TAG = 111;

const int ANS_TAG = 222;

/* MPI environment description */

int rank, size, provided;

MTEST_THREAD_RETURN_TYPE listener(void *);

/*

   LISTENER THREAD

   it waits for communication from any source (including calling thread)

   messages which it receives have tag REQ_TAG

   thread runs infinite loop which will stop only if every node in the

   MPI_COMM_WORLD send request containing -1

*/

MTEST_THREAD_RETURN_TYPE listener(void *extra)

{

    int req;

    int source;

    MPI_Status stat;

    int no_fins = 0;            /* this must be equal to size to break loop below */

    while (1) {

        /* wait for request */

        MPI_Recv(&req, 1, MPI_INT, MPI_ANY_SOURCE, REQ_TAG, MPI_COMM_WORLD, &stat;;

        /* get request source */

        source = stat.MPI_SOURCE;

        DEBUG(printf("node %d got request %d from %d\n", rank, req, source));

        if (req == -1)

            ++no_fins;  /* one more node finished requesting */

        /* no more requests can arrive */

        if (no_fins == size)

            break;

    }

    DEBUG(printf("node %d has stopped listener\n", rank));

    return MTEST_THREAD_RETVAL_IGN;

}

int main(int argc, char *argv[])

{

    int buf = 0;

    long int i, j;

    MTest_Init_thread(&argc, &argv, MPI_THREAD_MULTIPLE, &provided);

    if (provided != MPI_THREAD_MULTIPLE) {

        printf("This test requires MPI_THREAD_MULTIPLE\n");

        MPI_Abort(MPI_COMM_WORLD, 1);

    }

    MPI_Comm_rank(MPI_COMM_WORLD, &rank;;

    MPI_Comm_size(MPI_COMM_WORLD, &size);

    for (i = 0; i < NUM_ITER; i++) {

        /* create listener thread */

        MTest_Start_thread(listener, NULL);

        /* no more requests to send

         * inform other in the group that we have finished */

        buf = -1;

        for (j = 0; j < size; ++j) {

            MPI_Send(&buf, 1, MPI_INT, j, REQ_TAG, MPI_COMM_WORLD);

        }

        /* and wait for others to do the same */

        MTest_Join_threads();

        /* barrier to avoid deadlock */

        MPI_Barrier(MPI_COMM_WORLD);

    }

    MTest_Finalize(0);

    return 0;

}