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

/*

 *  (C) 2001 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include "mpi.h"

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

static void handle_error(int errcode, const char *str)

{

    char msg[MPI_MAX_ERROR_STRING];

    int resultlen;

    MPI_Error_string(errcode, msg, &resultlen);

    fprintf(stderr, "%s: %s\n", str, msg);

    MPI_Abort(MPI_COMM_WORLD, 1);

}

#define MPI_CHECK(fn) { int errcode; errcode = (fn); if (errcode != MPI_SUCCESS) handle_error(errcode, #fn); }

/* The file name is taken as a command-line argument. */

/* Measures the I/O bandwidth for writing/reading a 3D

   block-distributed array to a file corresponding to the global array

   in row-major (C) order.

   Note that the file access pattern is noncontiguous.

   Array size 128^3. For other array sizes, change array_of_gsizes below.*/

int main(int argc, char **argv)

{

    MPI_Datatype newtype;

    int i, ndims, array_of_gsizes[3], array_of_distribs[3];

    int order, nprocs, len, *buf, mynod;

    MPI_Count bufcount;

    int array_of_dargs[3], array_of_psizes[3];

    MPI_File fh;

    MPI_Status status;

    double stim, write_tim, new_write_tim, write_bw;

    double read_tim, new_read_tim, read_bw;

    char *filename;

    MPI_Init(&argc, &argv);

    MPI_Comm_rank(MPI_COMM_WORLD, &mynod);

    MPI_Comm_size(MPI_COMM_WORLD, &nprocs);

/* process 0 takes the file name as a command-line argument and

   broadcasts it to other processes */

    if (!mynod) {

        i = 1;

        while ((i < argc) && strcmp("-fname", *argv)) {

            i++;

            argv++;

        }

        if (i >= argc) {

            fprintf(stderr, "\n*#  Usage: coll_perf -fname filename\n\n");

            MPI_Abort(MPI_COMM_WORLD, 1);

        }

        argv++;

        len = strlen(*argv);

        filename = (char *) malloc(len + 1);

        strcpy(filename, *argv);

        MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);

        MPI_Bcast(filename, len + 1, MPI_CHAR, 0, MPI_COMM_WORLD);

    } else {

        MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);

        filename = (char *) malloc(len + 1);

        MPI_Bcast(filename, len + 1, MPI_CHAR, 0, MPI_COMM_WORLD);

    }

    ndims = 3;

    order = MPI_ORDER_C;

    array_of_gsizes[0] = 128 * 17;

    array_of_gsizes[1] = 128 * 9;

    array_of_gsizes[2] = 128 * 11;

    array_of_distribs[0] = MPI_DISTRIBUTE_BLOCK;

    array_of_distribs[1] = MPI_DISTRIBUTE_BLOCK;

    array_of_distribs[2] = MPI_DISTRIBUTE_BLOCK;

    array_of_dargs[0] = MPI_DISTRIBUTE_DFLT_DARG;

    array_of_dargs[1] = MPI_DISTRIBUTE_DFLT_DARG;

    array_of_dargs[2] = MPI_DISTRIBUTE_DFLT_DARG;

    for (i = 0; i < ndims; i++)

        array_of_psizes[i] = 0;

    MPI_Dims_create(nprocs, ndims, array_of_psizes);

    MPI_Type_create_darray(nprocs, mynod, ndims, array_of_gsizes,

                           array_of_distribs, array_of_dargs,

                           array_of_psizes, order, MPI_INT, &newtype);

    MPI_Type_commit(&newtype);

    MPI_Type_size_x(newtype, &bufcount);

    bufcount = bufcount / sizeof(int);

    buf = (int *) malloc(bufcount * sizeof(int));

/* to eliminate paging effects, do the operations once but don't time

   them */

    MPI_CHECK(MPI_File_open(MPI_COMM_WORLD, filename,

                            MPI_MODE_CREATE | MPI_MODE_RDWR, MPI_INFO_NULL, &fh));

    MPI_CHECK(MPI_File_set_view(fh, 0, MPI_INT, newtype, "native", MPI_INFO_NULL));

    MPI_CHECK(MPI_File_write_all(fh, buf, bufcount, MPI_INT, &status));

    MPI_CHECK(MPI_File_seek(fh, 0, MPI_SEEK_SET));

    MPI_CHECK(MPI_File_read_all(fh, buf, bufcount, MPI_INT, &status));

    MPI_CHECK(MPI_File_close(&fh));

    MPI_Barrier(MPI_COMM_WORLD);

/* now time write_all */

    MPI_CHECK(MPI_File_open(MPI_COMM_WORLD, filename,

                            MPI_MODE_CREATE | MPI_MODE_RDWR, MPI_INFO_NULL, &fh));

    MPI_CHECK(MPI_File_set_view(fh, 0, MPI_INT, newtype, "native", MPI_INFO_NULL));

    MPI_Barrier(MPI_COMM_WORLD);

    stim = MPI_Wtime();

    MPI_CHECK(MPI_File_write_all(fh, buf, bufcount, MPI_INT, &status));

    write_tim = MPI_Wtime() - stim;

    MPI_CHECK(MPI_File_close(&fh));

    MPI_Allreduce(&write_tim, &new_write_tim, 1, MPI_DOUBLE, MPI_MAX, MPI_COMM_WORLD);

    if (mynod == 0) {

        write_bw =

            (array_of_gsizes[0] * array_of_gsizes[1] * array_of_gsizes[2] * sizeof(int)) /

            (new_write_tim * 1024.0 * 1024.0);

        fprintf(stderr, "Global array size %d x %d x %d integers\n", array_of_gsizes[0],

                array_of_gsizes[1], array_of_gsizes[2]);

        fprintf(stderr,

                "Collective write time = %f sec, Collective write bandwidth = %f Mbytes/sec\n",

                new_write_tim, write_bw);

    }

    MPI_Barrier(MPI_COMM_WORLD);

/* now time read_all */

    MPI_CHECK(MPI_File_open(MPI_COMM_WORLD, filename,

                            MPI_MODE_CREATE | MPI_MODE_RDWR, MPI_INFO_NULL, &fh));

    MPI_CHECK(MPI_File_set_view(fh, 0, MPI_INT, newtype, "native", MPI_INFO_NULL));

    MPI_Barrier(MPI_COMM_WORLD);

    stim = MPI_Wtime();

    MPI_CHECK(MPI_File_read_all(fh, buf, bufcount, MPI_INT, &status));

    read_tim = MPI_Wtime() - stim;

    MPI_CHECK(MPI_File_close(&fh));

    MPI_Allreduce(&read_tim, &new_read_tim, 1, MPI_DOUBLE, MPI_MAX, MPI_COMM_WORLD);

    if (mynod == 0) {

        read_bw =

            (array_of_gsizes[0] * array_of_gsizes[1] * array_of_gsizes[2] * sizeof(int)) /

            (new_read_tim * 1024.0 * 1024.0);

        fprintf(stderr,

                "Collective read time = %f sec, Collective read bandwidth = %f Mbytes/sec\n",

                new_read_tim, read_bw);

    }

    MPI_Type_free(&newtype);

    free(buf);

    free(filename);

    MPI_Finalize();

    return 0;

}