Verifying on Memory behavior

verifying_memory.c

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

#define LENGTH (64UL*1024*1024)
#define INTERVAL 10

void print_time(char *buf){
	struct timespec ts;
	struct tm tm;

	clock_gettime(CLOCK_REALTIME, &ts);
	localtime_r( &ts.tv_sec, &tm);

	printf("%d/%02d/%02d %02d:%02d:%02d.%06ld: %s\n",
		tm.tm_year+1900,
		tm.tm_mon+1,
		tm.tm_mday,
		tm.tm_hour,
		tm.tm_min,
		tm.tm_sec,
		ts.tv_nsec/1000,
		buf);

	return;
}

static void check_bytes(unsigned long *addr)
{
	printf("First hex is %x\n", *((unsigned long *)addr));
}

static void write_bytes(unsigned long *addr)
{
	unsigned long i,count,point;

	point = LENGTH / 20;
	count = 0;
	for (i = 0; i < LENGTH; i++){
		*(addr + i) = (unsigned long)i;
		//printf("i=%10lu \n",i);
		count++;
		if( count >= point ){
			sleep(1);
			count=0;
		}
	}
	return;
}

static int read_bytes(unsigned long *addr)
{
	unsigned long i,count,point,dummy;

	point = LENGTH / 20;
	count = 0;
	check_bytes(addr);
	for (i = 0; i < LENGTH; i++){
		dummy = (unsigned long)*(addr + i);
		//printf("i=%10lu dummy=%10lu\n",i, dummy);
		count++;
		if( count >= point ){
			sleep(1);
			count=0;
		}
	}	
	return 0;
}

int main(void)
{
	unsigned long *addr;
	int ret;

	print_time("upped the test program");
	sleep(INTERVAL);

	print_time("step1 get virtual memory via malloc");
        addr = malloc(LENGTH * sizeof(unsigned long) );

	if (addr == NULL ) {
		perror("malloc");
		exit(1);
	}

	printf("Returned address is %p\n", addr);
	check_bytes(addr);

	sleep(INTERVAL);
	print_time("step2 start  reading");
	ret = read_bytes(addr);
	print_time("step2 finish reading");

	sleep(INTERVAL);
	print_time("step3 start  writing");
	write_bytes(addr);
	print_time("step3 finish writing");

	sleep(INTERVAL);
	print_time("step4 start  reading");
	ret = read_bytes(addr);
	print_time("step4 finish reading");

	/* munmap() length of MAP_HUGETLB memory must be hugepage aligned */
	sleep(INTERVAL);
	print_time("step5 free");
	free(addr);

	sleep(INTERVAL);
	print_time("quit the test promgram");

	return ret;
}

Pasear,
Thanks for your advice.
I have also confirmed that read_bytes function does not read too.
Therefore, I fixed the program.