cachetest.c

// CFLAGS='-std=c99 -arch x86_64' make cachetest && ./cachetest

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

void a();
void b();

int main() {
	time_t s;

	s = time(NULL);
	for (int i = 0; i < 100000; i++) a();
	printf("a %ld\n", time(NULL) - s);

	s = time(NULL);
	for (int i = 0; i < 100000; i++) b();
	printf("b %ld\n", time(NULL) - s);
}

void a() {
	unsigned long array[256][256];
	for (int i = 0; i < 256; i++) {
		for (int j = 0; j < 256; j++) {
			array[i][j] = i * j;
		}
	}
}


void b() {
	unsigned long array[256][256];
	for (int i = 0; i < 256; i++) {
		for (int j = 0; j < 256; j++) {
			array[j][i] = i * j;
		}
	}
}