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/* [ICS VERSION STRING: unknown] */
// mpi_pinned.c
//
// To run with, for example, Open MPI:
//  mpirun -x LD_LIBRARY_PATH -np 2 -host host1,host2 ./mpi_pinned
//
//////////////////////////////////////////////////////////////////////
#include <stdio.h>
#include <stdlib.h>
#include <cuda.h>
#include <cuda_runtime.h>
#include <sys/time.h>
#include <mpi.h>

#define NREPEAT 10
#define NBYTES  10.e6

void usage(const char * name)
{
    printf("Usage: %s -x LD_LIBRARY_PATH \\ \n"
           "          -np 2 -host computer1,computer2 _out/<arch>/mpi_pinned\n",
           name);
}

int main (int argc, char *argv[])
{
    int rank, size, n, len;
    int result;
    void *a_h, *a_d;
    struct timeval time[2];
    double bandwidth;
    char hostname[MPI_MAX_PROCESSOR_NAME];
    MPI_Status status;

    MPI_Init (&argc, &argv);
    MPI_Comm_rank (MPI_COMM_WORLD, &rank);
    MPI_Comm_size (MPI_COMM_WORLD, &size);

    MPI_Get_processor_name(hostname, &len);
    printf("Process %d is on %s\n", rank, hostname);

    if (argc > 1 && *argv[1] == 'h')
    {
        usage(argv[0]);
        exit(0);
    }

#ifdef PINNED
    cudaMallocHost( (void **) &a_h, NBYTES);
#else
    a_h = malloc(NBYTES);
#endif

    result = cudaMalloc( (void **) &a_d, NBYTES);
    if (result)
    {
        printf("ERROR: %s: cudaMalloc failed, error code: %d, which means: %s\n",
               hostname, result, cudaGetErrorString(result));
        exit(1);
    }

    /* Test host -> device bandwidth. */

    gettimeofday(&time[0], NULL);
    for (n=0; n<NREPEAT; n++)
    {
        result = cudaMemcpy(a_d, a_h, NBYTES, cudaMemcpyHostToDevice);
        if (result)
        {
            printf("ERROR: %s: cudaMemcpy failed, error code: %d, which means: %s\n",
                   hostname, result, cudaGetErrorString(result));
            exit(1);
        }

    }
    gettimeofday(&time[1], NULL);

    bandwidth  =        time[1].tv_sec  - time[0].tv_sec;
    bandwidth += 1.e-6*(time[1].tv_usec - time[0].tv_usec);
    bandwidth  = NBYTES*NREPEAT/1.e6/bandwidth;

    printf("Host->device bandwidth for process %d: %f MB/sec\n",rank,bandwidth);

    /* Test MPI send/recv bandwidth. */

    MPI_Barrier(MPI_COMM_WORLD);

    gettimeofday(&time[0], NULL);
    for (n=0; n<NREPEAT; n++)
    {
        if (rank == 0)
            MPI_Send(a_h, NBYTES/sizeof(int), MPI_INT, 1, 0, MPI_COMM_WORLD);
        else
            MPI_Recv(a_h, NBYTES/sizeof(int), MPI_INT, 0, 0, MPI_COMM_WORLD, &status);
    }
    gettimeofday(&time[1], NULL);

    bandwidth  =        time[1].tv_sec  - time[0].tv_sec;
    bandwidth += 1.e-6*(time[1].tv_usec - time[0].tv_usec);
    bandwidth  = NBYTES*NREPEAT/1.e6/bandwidth;

    if (rank == 0)
        printf("MPI send/recv bandwidth: %f MB/sec\n", bandwidth);

    cudaFree(a_d);

#ifdef PINNED
    cudaFreeHost(a_h);
#else
    free(a_h);
#endif

    MPI_Finalize();
    return 0;
}