Performance of sorting procedures

1. Results

   Those results were generated with vs2012 Release configuration and full optimization: (\Ox):
   sort (tmp.begin(),tmp.end(),less<int>()): 399.258 milliseconds
   sort (tmp.begin(),tmp.end()): 402.652 milliseconds
   sort (tmp.begin(),tmp.end(), (lessFunction<int>)): 2.11581 seconds
   qsort (&tmp[0],tmp.size(),sizeof(int), compare): 2.43363 seconds
   

2. Code

   #include <windows.h>
   
   #include <vector>
   #include <cstdlib>
   #include <iostream>
   #include <ostream>
   #include <sstream>
   #include <set>
   #include <string>
   #include <algorithm>
   #include <numeric>
   #include <future>
   #include <functional>
   
   using namespace std;
   size_t MAX_SIZE = (1 << 28) + 1;
   
   long long timer() {
       LARGE_INTEGER li;
       QueryPerformanceCounter(&li);
       return li.QuadPart;
   }
   long long frequency() {
       LARGE_INTEGER li;
       QueryPerformanceFrequency(&li);
       return li.QuadPart;
   }
   string format_time(const long long dt) {
       ostringstream oss;
       if ((dt) * 1000 < frequency()) {
           oss << (dt) * 1000000.0 / frequency() << " microseconds";
       } else if (dt < frequency()) {
           oss << (dt) * 1000.0 / frequency() << " milliseconds";
       } else {
           oss << (dt) * 1.0 / frequency() << " seconds";
       }
       return oss.str();
   }
   
   void fillRandomVector (vector <int> *v)
   {
       srand (0);
       for (auto i:*v)
           i = rand();
   }
   
   template <typename T>
   bool lessFunction(const T &d1, const T &d2)
   {
       return d1 < d2;
   }
   
   int compare (const void * a, const void * b)
   {
       return ( *(int*)a - *(int*)b );
   }
   
   int main()
   {
       typedef pair<long long, string> tTiemrResult;
       vector <tTiemrResult> tx;
   
       vector <int> tmp (MAX_SIZE);
   
       fillRandomVector (&tmp);
       tx.push_back(tTiemrResult(timer(),"start"));
       sort (tmp.begin(),tmp.end());
       tx.push_back(tTiemrResult(timer(),"sort (tmp.begin(),tmp.end())"));
   
       fillRandomVector (&tmp);
       tx.push_back(tTiemrResult(timer(),"start"));
       sort (tmp.begin(),tmp.end(),less<int>());
       tx.push_back(tTiemrResult(timer(),"sort (tmp.begin(),tmp.end(),less<int>())"));
   
       fillRandomVector (&tmp);
       tx.push_back(tTiemrResult(timer(),"start"));
       sort (tmp.begin(),tmp.end(), (lessFunction<int>));
       tx.push_back(tTiemrResult(timer(),"sort (tmp.begin(),tmp.end(), (lessFunction<int>))"));
   
       fillRandomVector (&tmp);
       tx.push_back(tTiemrResult(timer(),"start"));
       qsort (&tmp[0],tmp.size(),sizeof(int), compare);
       tx.push_back(tTiemrResult(timer(),"qsort (&tmp[0],tmp.size(),sizeof(int), compare)"));
   
       vector <tTiemrResult> tx2;
       for (size_t i=1; i < tx.size() ; i++)
           tx2.push_back(tTiemrResult(tx[i].first - tx[i-1].first, tx[i].second));
       sort (tx2.begin(), tx2.end());
       for (auto i:tx2)
           cout<<i.second<<": "<< format_time (i.first)<<endl;
       return 0;
   }