/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
 *  (C) 2008 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */
/*
 * This code may be used to test the performance of some of the
 * noncontiguous datatype operations, including vector and indexed
 * pack and unpack operations.  To simplify the use of this code for
 * tuning an MPI implementation, it uses no communication, just the
 * MPI_Pack and MPI_Unpack routines.  In addition, the individual tests are
 * in separate routines, making it easier to compare the compiler-generated
 * code for the user (manual) pack/unpack with the code used by
 * the MPI implementation.  Further, to be fair to the MPI implementation,
 * the routines are passed the source and destination buffers; this ensures
 * that the compiler can't optimize for statically allocated buffers.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "mpi.h"

/* Needed for restrict and const definitions */
#include "mpitestconf.h"

static int verbose = 0;

#define N_REPS 50
#define THRESHOLD 0.10
#define VARIANCE_THRESHOLD ((THRESHOLD * THRESHOLD) / 2)
#define NTRIALS 10

double mean(double *list, int count);
double mean(double *list, int count)
{
    double retval;
    int i;

    retval = 0;
    for (i = 0; i < count; i++)
        retval += list[i];
    retval /= count;

    return retval;
}

double noise(double *list, int count);
double noise(double *list, int count)
{
    double *margin, retval;
    int i;

    if (!(margin = malloc(count * sizeof(double)))) {
        printf("Unable to allocate memory\n");
        return -1;
    }

    for (i = 0; i < count; i++)
        margin[i] = list[i] / mean(list, count);

    retval = 0;
    for (i = 0; i < count; i++) {
        retval += ((margin[i] - 1) * (margin[i] - 1));
    }
    retval /= count;
    if (retval < 0)
        retval = -retval;

    free(margin);
    return retval;
}

/* Here are the tests */

/* Test packing a vector of individual doubles */
/* We don't use restrict in the function args because assignments between
   restrict pointers is not valid in C and some compilers, such as the
   IBM xlc compilers, flag that use as an error.*/
int TestVecPackDouble(int n, int stride,
                      double *avgTimeUser, double *avgTimeMPI, double *dest, const double *src);
int TestVecPackDouble(int n, int stride,
                      double *avgTimeUser, double *avgTimeMPI, double *dest, const double *src)
{
    double *restrict d_dest;
    const double *restrict d_src;
    register int i, j;
    int rep, position;
    double t1, t2, t[NTRIALS];
    MPI_Datatype vectype;

    /* User code */
    if (verbose)
        printf("TestVecPackDouble (USER): ");
    for (j = 0; j < NTRIALS; j++) {
        t1 = MPI_Wtime();
        for (rep = 0; rep < N_REPS; rep++) {
            i = n;
            d_dest = dest;
            d_src = src;
            while (i--) {
                *d_dest++ = *d_src;
                d_src += stride;
            }
        }
        t2 = MPI_Wtime() - t1;
        t[j] = t2;
        if (verbose)
            printf("%.3f ", t[j]);
    }
    if (verbose)
        printf("[%.3f]\n", noise(t, NTRIALS));
    /* If there is too much noise, discard the test */
    if (noise(t, NTRIALS) > VARIANCE_THRESHOLD) {
        *avgTimeUser = 0;
        *avgTimeMPI = 0;
        if (verbose)
            printf("Too much noise; discarding measurement\n");
        return 0;
    }
    *avgTimeUser = mean(t, NTRIALS) / N_REPS;

    /* MPI Vector code */
    MPI_Type_vector(n, 1, stride, MPI_DOUBLE, &vectype);
    MPI_Type_commit(&vectype);

    if (verbose)
        printf("TestVecPackDouble (MPI): ");
    for (j = 0; j < NTRIALS; j++) {
        t1 = MPI_Wtime();
        for (rep = 0; rep < N_REPS; rep++) {
            position = 0;
            MPI_Pack((void *) src, 1, vectype, dest, n * sizeof(double), &position, MPI_COMM_SELF);
        }
        t2 = MPI_Wtime() - t1;
        t[j] = t2;
        if (verbose)
            printf("%.3f ", t[j]);
    }
    if (verbose)
        printf("[%.3f]\n", noise(t, NTRIALS));
    /* If there is too much noise, discard the test */
    if (noise(t, NTRIALS) > VARIANCE_THRESHOLD) {
        *avgTimeUser = 0;
        *avgTimeMPI = 0;
        if (verbose)
            printf("Too much noise; discarding measurement\n");
    }
    else {
        *avgTimeMPI = mean(t, NTRIALS) / N_REPS;
    }

    MPI_Type_free(&vectype);

    return 0;
}

/* Test unpacking a vector of individual doubles */
/* See above for why restrict is not used in the function args */
int TestVecUnPackDouble(int n, int stride,
                        double *avgTimeUser, double *avgTimeMPI, double *dest, const double *src);
int TestVecUnPackDouble(int n, int stride,
                        double *avgTimeUser, double *avgTimeMPI, double *dest, const double *src)
{
    double *restrict d_dest;
    const double *restrict d_src;
    register int i, j;
    int rep, position;
    double t1, t2, t[NTRIALS];
    MPI_Datatype vectype;

    /* User code */
    if (verbose)
        printf("TestVecUnPackDouble (USER): ");
    for (j = 0; j < NTRIALS; j++) {
        t1 = MPI_Wtime();
        for (rep = 0; rep < N_REPS; rep++) {
            i = n;
            d_dest = dest;
            d_src = src;
            while (i--) {
                *d_dest = *d_src++;
                d_dest += stride;
            }
        }
        t2 = MPI_Wtime() - t1;
        t[j] = t2;
        if (verbose)
            printf("%.3f ", t[j]);
    }
    if (verbose)
        printf("[%.3f]\n", noise(t, NTRIALS));
    /* If there is too much noise, discard the test */
    if (noise(t, NTRIALS) > VARIANCE_THRESHOLD) {
        *avgTimeUser = 0;
        *avgTimeMPI = 0;
        if (verbose)
            printf("Too much noise; discarding measurement\n");
        return 0;
    }
    *avgTimeUser = mean(t, NTRIALS) / N_REPS;

    /* MPI Vector code */
    MPI_Type_vector(n, 1, stride, MPI_DOUBLE, &vectype);
    MPI_Type_commit(&vectype);

    if (verbose)
        printf("TestVecUnPackDouble (MPI): ");
    for (j = 0; j < NTRIALS; j++) {
        t1 = MPI_Wtime();
        for (rep = 0; rep < N_REPS; rep++) {
            position = 0;
            MPI_Unpack((void *) src, n * sizeof(double),
                       &position, dest, 1, vectype, MPI_COMM_SELF);
        }
        t2 = MPI_Wtime() - t1;
        t[j] = t2;
        if (verbose)
            printf("%.3f ", t[j]);
    }
    if (verbose)
        printf("[%.3f]\n", noise(t, NTRIALS));
    /* If there is too much noise, discard the test */
    if (noise(t, NTRIALS) > VARIANCE_THRESHOLD) {
        *avgTimeUser = 0;
        *avgTimeMPI = 0;
        if (verbose)
            printf("Too much noise; discarding measurement\n");
    }
    else {
        *avgTimeMPI = mean(t, NTRIALS) / N_REPS;
    }

    MPI_Type_free(&vectype);

    return 0;
}

/* Test packing a vector of 2-individual doubles */
/* See above for why restrict is not used in the function args */
int TestVecPack2Double(int n, int stride,
                       double *avgTimeUser, double *avgTimeMPI, double *dest, const double *src);
int TestVecPack2Double(int n, int stride,
                       double *avgTimeUser, double *avgTimeMPI, double *dest, const double *src)
{
    double *restrict d_dest;
    const double *restrict d_src;
    register int i, j;
    int rep, position;
    double t1, t2, t[NTRIALS];
    MPI_Datatype vectype;

    /* User code */
    if (verbose)
        printf("TestVecPack2Double (USER): ");
    for (j = 0; j < NTRIALS; j++) {
        t1 = MPI_Wtime();
        for (rep = 0; rep < N_REPS; rep++) {
            i = n;
            d_dest = dest;
            d_src = src;
            while (i--) {
                *d_dest++ = d_src[0];
                *d_dest++ = d_src[1];
                d_src += stride;
            }
        }
        t2 = MPI_Wtime() - t1;
        t[j] = t2;
        if (verbose)
            printf("%.3f ", t[j]);
    }
    if (verbose)
        printf("[%.3f]\n", noise(t, NTRIALS));
    /* If there is too much noise, discard the test */
    if (noise(t, NTRIALS) > VARIANCE_THRESHOLD) {
        *avgTimeUser = 0;
        *avgTimeMPI = 0;
        if (verbose)
            printf("Too much noise; discarding measurement\n");
        return 0;
    }
    *avgTimeUser = mean(t, NTRIALS) / N_REPS;

    /* MPI Vector code */
    MPI_Type_vector(n, 2, stride, MPI_DOUBLE, &vectype);
    MPI_Type_commit(&vectype);

    if (verbose)
        printf("TestVecPack2Double (MPI): ");
    for (j = 0; j < NTRIALS; j++) {
        t1 = MPI_Wtime();
        for (rep = 0; rep < N_REPS; rep++) {
            position = 0;
            MPI_Pack((void *) src, 1, vectype, dest, 2 * n * sizeof(double),
                     &position, MPI_COMM_SELF);
        }
        t2 = MPI_Wtime() - t1;
        t[j] = t2;
        if (verbose)
            printf("%.3f ", t[j]);
    }
    if (verbose)
        printf("[%.3f]\n", noise(t, NTRIALS));
    /* If there is too much noise, discard the test */
    if (noise(t, NTRIALS) > VARIANCE_THRESHOLD) {
        *avgTimeUser = 0;
        *avgTimeMPI = 0;
        if (verbose)
            printf("Too much noise; discarding measurement\n");
    }
    else {
        *avgTimeMPI = mean(t, NTRIALS) / N_REPS;
    }
    MPI_Type_free(&vectype);

    return 0;
}

/* This creates an indexed type that is like a vector (for simplicity
   of construction).  There is a possibility that the MPI implementation
   will recognize and simplify this (e.g., in MPI_Type_commit); if so,
   let us know and we'll add a version that is not as regular
*/
/* See above for why restrict is not used in the function args */
int TestIndexPackDouble(int n, int stride,
                        double *avgTimeUser, double *avgTimeMPI, double *dest, const double *src);
int TestIndexPackDouble(int n, int stride,
                        double *avgTimeUser, double *avgTimeMPI, double *dest, const double *src)
{
    double *restrict d_dest;
    const double *restrict d_src;
    register int i, j;
    int rep, position;
    int *restrict displs = 0;
    double t1, t2, t[NTRIALS];
    MPI_Datatype indextype;

    displs = (int *) malloc(n * sizeof(int));
    for (i = 0; i < n; i++)
        displs[i] = i * stride;

    /* User code */
    if (verbose)
        printf("TestIndexPackDouble (USER): ");
    for (j = 0; j < NTRIALS; j++) {
        t1 = MPI_Wtime();
        for (rep = 0; rep < N_REPS; rep++) {
            i = n;
            d_dest = dest;
            d_src = src;
            for (i = 0; i < n; i++) {
                *d_dest++ = d_src[displs[i]];
            }
        }
        t2 = MPI_Wtime() - t1;
        t[j] = t2;
        if (verbose)
            printf("%.3f ", t[j]);
    }
    if (verbose)
        printf("[%.3f]\n", noise(t, NTRIALS));
    /* If there is too much noise, discard the test */
    if (noise(t, NTRIALS) > VARIANCE_THRESHOLD) {
        *avgTimeUser = 0;
        *avgTimeMPI = 0;
        if (verbose)
            printf("Too much noise; discarding measurement\n");
        return 0;
    }
    *avgTimeUser = mean(t, NTRIALS) / N_REPS;

    /* MPI Index code */
    MPI_Type_create_indexed_block(n, 1, displs, MPI_DOUBLE, &indextype);
    MPI_Type_commit(&indextype);

    free(displs);

    if (verbose)
        printf("TestIndexPackDouble (MPI): ");
    for (j = 0; j < NTRIALS; j++) {
        t1 = MPI_Wtime();
        for (rep = 0; rep < N_REPS; rep++) {
            position = 0;
            MPI_Pack((void *) src, 1, indextype, dest, n * sizeof(double),
                     &position, MPI_COMM_SELF);
        }
        t2 = MPI_Wtime() - t1;
        t[j] = t2;
        if (verbose)
            printf("%.3f ", t[j]);
    }
    if (verbose)
        printf("[%.3f]\n", noise(t, NTRIALS));
    /* If there is too much noise, discard the test */
    if (noise(t, NTRIALS) > VARIANCE_THRESHOLD) {
        *avgTimeUser = 0;
        *avgTimeMPI = 0;
        if (verbose)
            printf("Too much noise; discarding measurement\n");
    }
    else {
        *avgTimeMPI = mean(t, NTRIALS) / N_REPS;
    }
    MPI_Type_free(&indextype);

    return 0;
}

int Report(const char *name, const char *packname, double avgTimeMPI, double avgTimeUser);
int Report(const char *name, const char *packname, double avgTimeMPI, double avgTimeUser)
{
    double diffTime, maxTime;
    int errs = 0;

    /* Move this into a common routine */
    diffTime = avgTimeMPI - avgTimeUser;
    if (diffTime < 0)
        diffTime = -diffTime;
    if (avgTimeMPI > avgTimeUser)
        maxTime = avgTimeMPI;
    else
        maxTime = avgTimeUser;

    if (verbose) {
        printf("%-30s:\t%g\t%g\t(%g%%)\n", name,
               avgTimeMPI, avgTimeUser, 100 * (diffTime / maxTime));
        fflush(stdout);
    }
    if (avgTimeMPI > avgTimeUser && (diffTime > THRESHOLD * maxTime)) {
        errs++;
        printf("%s:\tMPI %s code is too slow: MPI %g\t User %g\n",
               name, packname, avgTimeMPI, avgTimeUser);
    }

    return errs;
}

/* Finally, here's the main program */
int main(int argc, char *argv[])
{
    int n, stride, errs = 0;
    void *dest, *src;
    double avgTimeUser, avgTimeMPI;

    MPI_Init(&argc, &argv);
    if (getenv("MPITEST_VERBOSE"))
        verbose = 1;

    n = 30000;
    stride = 4;
    dest = (void *) malloc(n * sizeof(double));
    src = (void *) malloc(n * ((1 + stride) * sizeof(double)));
    /* Touch the source and destination arrays */
    memset(src, 0, n * (1 + stride) * sizeof(double));
    memset(dest, 0, n * sizeof(double));

    TestVecPackDouble(n, stride, &avgTimeUser, &avgTimeMPI, dest, src);
    errs += Report("VecPackDouble", "Pack", avgTimeMPI, avgTimeUser);

    TestVecUnPackDouble(n, stride, &avgTimeUser, &avgTimeMPI, src, dest);
    errs += Report("VecUnPackDouble", "Unpack", avgTimeMPI, avgTimeUser);

    TestIndexPackDouble(n, stride, &avgTimeUser, &avgTimeMPI, dest, src);
    errs += Report("VecIndexDouble", "Pack", avgTimeMPI, avgTimeUser);

    free(dest);
    free(src);

    dest = (void *) malloc(2 * n * sizeof(double));
    src = (void *) malloc((1 + n) * ((1 + stride) * sizeof(double)));
    memset(dest, 0, 2 * n * sizeof(double));
    memset(src, 0, (1 + n) * (1 + stride) * sizeof(double));
    TestVecPack2Double(n, stride, &avgTimeUser, &avgTimeMPI, dest, src);
    errs += Report("VecPack2Double", "Pack", avgTimeMPI, avgTimeUser);

    free(dest);
    free(src);



    if (errs == 0) {
        printf(" No Errors\n");
    }
    else {
        printf(" Found %d performance problems\n", errs);
    }

    fflush(stdout);
    MPI_Finalize();

    return 0;
}
