update

Signed-off-by: Wenchao Hao <haowenchao22@gmail.com>

madvise.c

@@ -0,0 +1,36 @@
+#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()
+{
+	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)));
+}