https://blog.csdn.net/mrpre/article/details/83586778

效能效果：hugepages》mmap》normal

gcc xxx

sudo perf record -e dTLB-loads -e faults ./a.out
sudo perf report

normal：

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <inttypes.h>
 4 #include <sys/types.h>
 5 #include <unistd.h>
 6
 
 #include <fcntl.h>
 7 #include <sys/mman.h>
 8 #include <malloc.h>
 9 void access_mem(char *ptr, unsigned long memsize)
10 {
11 unsigned long i;
12 for (i = 0; i < memsize; i+=4096) {
13 ptr[i] = 1;
14 }
15 
16 }
17 int main() {
18 unsigned long memsize = 1000000000;
19 
20 char *my_string = malloc
 
(memsize);
21 access_mem(my_string, memsize);
22 }
23 
24 ~

mmap：

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <inttypes.h>
 4 #include <sys/types.h>
 5 #include <unistd.h>
 6 #include <fcntl.h>
 7 #include <sys/mman.h>
 8 
 9 void access_mem(char
 
 *ptr, unsigned long memsize)
10 {
11 unsigned long i;
12 for (i = 0; i < memsize; i+=4096) {
13 ptr[i] = 1;
14 }
15 
16 }
17 int main() {
18 unsigned long memsize = 1000000000;
19 unsigned long i;
20 
21 int fd = open("/dev/hugepages/fileA", O_CREAT|O_RDWR, 0600);
22 
23 char *my_string = mmap(0, memsize, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
24 
25 access_mem(my_string, memsize);
26 }

hugepages：

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <inttypes.h>
 4 #include <sys/types.h>
 5 #include <unistd.h>
 6 #include <fcntl.h>
 7 #include <sys/mman.h>
 8 
 9 void access_mem(char *ptr, unsigned long memsize)
10 {
11 unsigned long i;
12 for (i = 0; i < memsize; i+=4096) {
13 ptr[i] = 1;
14 }
15 
16 }
17 int main() {
18 unsigned long memsize = 1000000000;
19 unsigned long i;
20 
21 
22 char *my_string = mmap(0, memsize, PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB/**/, -1, 0);
23 
24 access_mem(my_string, memsize);
25 
26 sleep(20);
27 munmap(my_string, memsize);
28 
29 }