C++执行内存memcpy的效率测试

 1 #include <iostream>
 2 #include <sys/time.h>
 3 #include <string.h>
 4 
 5 using namespace std;
 6 
 7 int main(int argc, char* argv[])
 8 {
 9         long len = 8192;
10         int  loop = 200;
11         char* p = new char[len];
12         char* q = p;
13         struct timeval start, end;
14         gettimeofday(&start, NULL);
15         for (int i =0; i < loop; ++i)
16         {
17                 char* p = new char[len];
18                 *p = char(i);
19                 memcpy(p, q, len);
20                 delete [] p;
21         }
22         gettimeofday(&end, NULL);
23         cout <<"do memcpy speed:" << ((end.tv_sec - start.tv_sec)*1000 + double(end.tv_usec - start.tv_usec) / (len*loop/1000/1000) ) / loop<<" ms/MB\n";
24         cout <<"each thread can do memcpy "<< double(len)*loop/1000/1000 / ((end.tv_sec - start.tv_sec) + double(end.tv_usec - start.tv_usec) / 1000/1000) <<" MB\n";
25 
26 }