Persudo random generator according to benchmark

persudo_random_generator.c

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

int main(void)
{
        int i, j, k;
        int dim = 11;
        int num = 1024 * 1024;
        int loop = 1000;
        struct timespec start, end;
        size_t stat[200] = { 0 };

        for (k = 0; k < loop; k++) {
                usleep(50000);
                srandom(time(NULL));
                clock_gettime(CLOCK_MONOTONIC, &start);
                for (i = 0; i < num; i++) {
                        double *vector = malloc(dim * sizeof(double));
                        for (j = 0; j < dim; j++) {
                                vector[j] = (double) random() / RAND_MAX * 20 - 10;
                        }
                        free(vector);
                }
                clock_gettime(CLOCK_MONOTONIC, &end);
                size_t rand_ms = (end.tv_sec - start.tv_sec)*1000 + (end.tv_nsec - start.tv_nsec)/1000000;
                stat[rand_ms]++;
        }

        for (i = 0; i < sizeof(stat)/sizeof(*stat); i++) {
                printf("[%d](%f\%):", i, 100.0 * stat[i] / loop);
                for (j = 0; j < stat[i]; j++) {
                        putchar('-');
                }
                putchar('\n');
        }

        return 0;
}