program that trys but fails to demonstrate cache locality (c learning)

cache_lcality.c

/* gcc -o out main.c && ./out */
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

typedef struct {
  int x;
  int y;
} Point;
/*
 * [xyxyxyxyxyxyxyxy]
 */

typedef struct {
  int *x;
  int *y;
} PointColumns;
/*
 * [xxxxxxxxyyyyyyyy]
 */

// CPU registers tiny
// lvl 1 cache   smol
// lvl 2 cache   small
// lvl 3 cache   medium
// main memory   large+slow
// disk          massive+slow

#define COUNT 10

int main() {
  // Intialize records.
  Point *records10 = (Point *)malloc(sizeof(Point) * COUNT);
  for (int i = 0; i < COUNT; i++) {
    records10[i].x = i * 2;
    records10[i].y = i * 4;
  }
  for (int i = 0; i < COUNT; i++) {
    printf("%03d: x = %d y = %d\n", i, records10[i].x, records10[i].y);
  }

  // Intialize columns
  PointColumns columns10;
  columns10.x = (int *)malloc(sizeof(int) * COUNT);
  columns10.y = (int *)malloc(sizeof(int) * COUNT);
  for (int i = 0; i < COUNT; i++) {
    columns10.x[i] = i * 2;
    columns10.y[i] = i * 4;
  }
  for (int i = 0; i < COUNT; i++) {
    printf("%03d: x = %d y = %d\n", i, columns10.x[i], columns10.y[i]);
  }

  // Time increment x by 1 (records)
  {
    clock_t start, end;
    double cpu_time_used;

    for (int i = 0; i < COUNT; i++)
      records10[i].x += 1;

    start = clock();
    end = clock();
    cpu_time_used = ((double)(end - start)) / CLOCKS_PER_SEC;
    printf("records took: %f\n", cpu_time_used);
  }

  // Time increment x by 1 (columns)
  {
    clock_t start, end;
    double cpu_time_used;

    for (int i = 0; i < COUNT; i++)
      columns10.x[i] += 1;

    start = clock();
    end = clock();
    cpu_time_used = ((double)(end - start)) / CLOCKS_PER_SEC;
    printf("columns took: %f\n", cpu_time_used);
  }
}