void *p = malloc(4096 * max);

start = usec();

for (i = 0; i < max; i++) {

memcpy(p + i * 4096, page, 4096);

}

end = usec();

printf("%s : %d time use %lu us \n", __func__, max,end - start）;

static unsigned long usec(void)

{

struct timeval tv;

gettimeofday(&tv, 0);

return (unsigned long)tv.tv_sec * 1000000 + tv.tv_usec;

}

I'm don't think it's really precise but i did notice a difference ,

2018-07-08 2:44 GMT+08:00 <valdis.kletnieks@vt.edu>:

On Sat, 07 Jul 2018 19:36:47 +0800, bing zhu said:

> and in user space i do the same thing,I noticed that kernel is faster than
> user ,

How did you measure the times? Doing this right is actually harder than it looks...