Performance of summing procedures.

1. Results
   Those results were generated with vs2012 Release configuration and full optimization:
   
   /c /Zi /nologo /W4 /WX- /Ox /Oy- /GL /D WIN32 /D NDEBUG /D _CONSOLE /D _UNICODE /D UNICODE /Gm- /EHsc /MD /GS /Gy /fp:precise /Zc:wchar_t /Zc:forScope /Fo"RELEASE\\" /Fd"RELEASE\VC110.PDB" /Gd /TP /analyze-
   
   
   asyncTabIndexedSum: 1.69146 seconds (2 cores)
   tabIndexedSum: 2.37756 seconds (optimized for SSE)
   vectorIndexedSum: 3.04009 seconds
   accumulateTabSum: 3.24292 seconds
   accumulateVectorSum: 3.31494 seconds
   vectorRangedSum: 3.35942 seconds
   tabPointeredSum: 3.45808 seconds
2. Code
   
   #include <tchar.h>
   #include <windows.h>
   #include <vector>
   #include <cstdlib>
   #include <iostream>
   #include <ostream>
   #include <sstream>
   #include <set>
   #include <string>
   #include <algorithm>
   #include <numeric>
   #include <future>
   using namespace std;
   size_t MAX_SIZE = (1 << 28) + 1;
   size_t MAX_REPEATS = 10;
   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();
   }
   int tabIndexedSum (const int tab[], size_t tabSize)
   {
       int sum = 0;
       for (size_t i = 0; i<tabSize; ++i)
           sum += tab[i];
       return sum;
   }
   int tabPointeredSum (const int *tabBegin, const int *tabEnd)
   {
       int sum = 0;
       for (const int *i = tabBegin; i < tabEnd; ++i)
           sum += *i;
       return sum;
   }
   int vectorIndexedSum (const vector <int> &tab)
   {
       int sum = 0;
       for (size_t i=0;i<tab.size();++i)
           sum += tab[i];
       return sum;
   }
   int vectorRangedSum (const vector <int> &tab)
   {
       int sum = 0;
       for (auto i:tab)
           sum += i;
       return sum;
   }
   int accumulateVectorSum (const vector <int> &tab)
   {
       return accumulate (tab.begin(), tab.end(), 0);
   }
   int accumulateTabSum (const int tab[], size_t tabSize)
   {
       return accumulate (tab, tab + tabSize, 0);
   }
   int asyncTabIndexedSum (const int *tab, size_t tabSize)
   {
       size_t halfSize = tabSize / 2;
       auto s1 = async(launch::async, tabIndexedSum, tab, halfSize);
       auto s2 = async(launch::async, tabIndexedSum, tab +  halfSize, tabSize - halfSize);
       return s1.get() + s2.get();
   }
   int _tmain(int argc, _TCHAR argv[])
   {
       typedef pair<long long, string> tTiemrResult;
       vector <tTiemrResult> tx;
       vector <int> results;
       vector <int> tmp (MAX_SIZE);
       for (size_t i = 0; i < MAX_SIZE; ++i)
           tmp [i] = rand();
     
       tx.push_back(tTiemrResult(timer(),"start"));
       for (size_t i=0;i<MAX_REPEATS;++i)
           results.push_back(tabPointeredSum (&tmp[0], &tmp[0] + MAX_SIZE));
       tx.push_back(tTiemrResult(timer(),"tabPointeredSum"));
       for (size_t i=0;i<MAX_REPEATS;++i)
           results.push_back(tabIndexedSum (&tmp[0], MAX_SIZE));
       tx.push_back(tTiemrResult(timer(),"tabIndexedSum"));
       for (size_t i=0;i<MAX_REPEATS;++i)
           results.push_back(accumulateTabSum (&tmp[0], MAX_SIZE));
       tx.push_back(tTiemrResult(timer(),"accumulateTabSum"));
       for (size_t i=0;i<MAX_REPEATS;++i)
           results.push_back(asyncTabIndexedSum (&tmp[0], MAX_SIZE));
       tx.push_back(tTiemrResult(timer(),"asyncTabIndexedSum"));
       for (size_t i=0;i<MAX_REPEATS;++i)
           results.push_back(vectorIndexedSum (tmp));
       tx.push_back(tTiemrResult(timer(),"vectorIndexedSum"));
       for (size_t i=0;i<MAX_REPEATS;++i)
           results.push_back(vectorRangedSum (tmp));
       tx.push_back(tTiemrResult(timer(),"vectorRangedSum"));
       for (size_t i=0;i<MAX_REPEATS;++i)
           results.push_back(accumulateVectorSum (tmp));
       tx.push_back(tTiemrResult(timer(),"accumulateVectorSum"));
       cout << "resultSet: ";
       for (auto i:set <int> (results.begin(),results.end()))
            cout<< i<<", ";
       cout << endl;
       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;
   }