memory_test/madvise.c

#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;
	int j = 0;
	struct timeval tv_b, tv_e;;
#define SIZE 100*1024*1024
	unsigned long *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);

	for (j = 0; j < SIZE / 8; j+=128)
		*(p + j) = j;

	for (i = 0; i < 3; i++) {
		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)));
		
		gettimeofday(&tv_b, NULL);
		for (j = 0; j < SIZE / 8; j+=128)
			*(p + j) = j;
		gettimeofday(&tv_e, NULL);
		printf("swp in  bandwidth: %ld bytes/ms\n",
				SIZE/(tv_to_ms(tv_e) - tv_to_ms(tv_b)));
	}

	//madvise(p, SIZE, MADV_PAGEOUT);

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