Царю челобитная

#include <stdio.h>
#include <stdlib.h>

#define N 40000000
#define M 10

#include <sys/time.h>
#include <stdlib.h>

double gettime ()
{
    struct timeval tv;
    gettimeofday (&tv, NULL);
    return (double)tv.tv_sec + (0.000001 * (double)tv.tv_usec);
}

double sum1 (double *a, int n)
{
    int i;
    double sum = 0;
    for (i=0; i<n; i+=4)
    {
        sum += a[i+0];
        sum += a[i+1];
        sum += a[i+2];
        sum += a[i+3];
    }
    return sum;
}

double sum2 (double *a, int n)
{
    int i;
    double sum1=0, sum2=0, sum3=0, sum4=0;
    for (i=0; i<n; i+=4)
    {
        sum1 += a[i+0];
        sum2 += a[i+1];
        sum3 += a[i+2];
        sum4 += a[i+3];
    }
    return sum1+sum2+sum3+sum4;
}

int main ()
{
    double *array = malloc (N * sizeof (double));
    int i;
    double time;
    double s;
    for (i=0; i<N; i++) array[i] = 2;

    time = gettime();
    s = 0;
    for (i=0; i<M; i++) s += sum2 (array, N);
    time = gettime() - time;
    printf ("%f %f\n", s, time);

    time = gettime();
    s = 0;
    for (i=0; i<M; i++) s += sum1 (array, N);
    time = gettime() - time;
    printf ("%f %f\n", s, time);

    free (array);
    return 0;
}