Re: [boost] What's wrong with this benchmark

I think there is definitely something not quite right. One thing I notice is that the line: sample.push_back(get_clock() - base_clock); Is being timed. Which could potentially access a new memory page I think. In pin_thread you have _MSVC_VER instead of _MSC_VER Hacking up std::vector and adding a push_back_reserved that does no bounds checks I get consistently very strange timings. (Code included at the bottom to make it obvious that the latter should be no slower). X std::vector::push_back 0 0 100 765.360000 200 1537.260000 400 3037.950000 800 6008.280000 1600 11905.150000 3200 23950.320000 6400 48064.600000 12800 96178.470000 25600 190637.270000 51200 379025.420000 102400 757784.880000 204800 1514584.120000 409600 3026480.680000 819200 6050654.130000 X std::vector::push_back_reserved 0 0 100 938.090000 200 1936.380000 400 3704.400000 800 7274.170000 1600 14307.310000 3200 28550.140000 6400 56835.310000 12800 113579.430000 25600 226906.070000 51200 453802.040000 102400 911835.760000 204800 1819723.520000 409600 3639619.650000 819200 7281897.560000 My simpler, and I'm sure in many ways inferior benchmark, shows much more believable results. http://codepad.org/SBZ4rbqo Running 1 test case... std::vector::push_back_reserved 4.88 std::vector::push_back 6.31 bst::devector::push_back 5.37 bst::vector::push_back 7.22 void push_back(value_type&& _Val) { // insert by moving into element at end if (_Inside(_STD addressof(_Val))) { // push back an element size_type _Idx = _STD addressof(_Val) - this->_Myfirst(); if (this->_Mylast() == this->_Myend()) _Reserve(1); _Orphan_range(this->_Mylast(), this->_Mylast()); this->_Getal().construct(this->_Mylast(), _STD forward(this->_Myfirst()[_Idx])); ++this->_Mylast(); } else { // push back a non-element if (this->_Mylast() == this->_Myend()) _Reserve(1); _Orphan_range(this->_Mylast(), this->_Mylast()); this->_Getal().construct(this->_Mylast(), _STD forward(_Val)); ++this->_Mylast(); } } void push_back_reserved( value_type&& _Val ) { this->_Getal().construct( this->_Mylast(), _STD forward( _Val ) ); ++this->_Mylast(); }