基于C++执行内存memcpy效率测试的分析

#include <iostream>
 #include <sys/time.h>
 #include <string.h>

 using namespace std;

 int main(int argc, char* argv[])
 {
         long len = 8192;
         int  loop = 200;
         char* p = new char[len];
         char* q = p;
         struct timeval start, end;
         gettimeofday(&start, NULL);
         for (int i =0; i < loop; ++i)
         {
                 char* p = new char[len];
                 *p = char(i);
                 memcpy(p, q, len);
                 delete [] p;
         }
         gettimeofday(&end, NULL);
         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";
         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";

 }