#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <sys/time.h>

unsigned long long tv_to_ms(struct timeval tv)
{
	return tv.tv_sec * 1000 + tv.tv_usec / 1000;
}

void main()
{
	char c;
	pid_t pid;
	int i;
	struct timeval tv_b, tv_e;;
#define SIZE 400*1024*1024
	void *p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE,
				MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	if (!p) {
		perror("fail to get memory");
		exit(-1);
	}

	madvise(p, SIZE, MADV_HUGEPAGE);
	memset(p, 0x11, SIZE); /* write to get mem */

	gettimeofday(&tv_b, NULL);
	madvise(p, SIZE, MADV_PAGEOUT);
	gettimeofday(&tv_e, NULL);

	printf("swp out bandwidth: %ld bytes/ms\n",
			SIZE/(tv_to_ms(tv_e) - tv_to_ms(tv_b)));
	
	pid = fork();

	if (pid) {
		//scanf("%c", &c);
		gettimeofday(&tv_b, NULL);
		memset(p, 0x33, SIZE); /* write to get mem */
		gettimeofday(&tv_e, NULL);
		printf("swp in  bandwidth: %ld bytes/ms\n",
				SIZE/(tv_to_ms(tv_e) - tv_to_ms(tv_b)));
	}

	while(1) {
		sleep(100);
	}
}