HRTimer

class HRTimer {
public:
    HRTimer();
    void Start() ;
    void Stop();
    void Reset();
    double GetTotalMS();

private:
    DWORD processor;
    DWORD_PTR affinityMask;
    LARGE_INTEGER start;
    LARGE_INTEGER stop;
    LARGE_INTEGER total;
    double msMultiplier;
};

HRTimer::HRTimer()
    : start(), stop(), total(), processor(0), affinityMask(0)
{
    LARGE_INTEGER proc_freq;
    processor = ::GetCurrentProcessorNumber();
    affinityMask = ::SetThreadAffinityMask(::GetCurrentThread(), 1 << processor);
    ::QueryPerformanceFrequency(&proc_freq);
    ::SetThreadAffinityMask(::GetCurrentThread(), MAXSSIZE_T);
    msMultiplier =  1.0 / (proc_freq.QuadPart / 1000.0);
}

void HRTimer::Start(void)
{
    affinityMask = ::SetThreadAffinityMask(::GetCurrentThread(), 1 << processor);
    ::QueryPerformanceCounter(&start);
    ::SetThreadAffinityMask(::GetCurrentThread(), MAXSSIZE_T);
}

void HRTimer::Stop(void)
{
    ::SetThreadAffinityMask(::GetCurrentThread(), 1 << processor);
    ::QueryPerformanceCounter(&stop);
    ::SetThreadAffinityMask(::GetCurrentThread(), affinityMask);
    total.QuadPart += (stop.QuadPart - start.QuadPart);
}

void HRTimer::Reset(void)
{
    total.QuadPart = 0;
}

double HRTimer::GetTotalMS(void)
{
    return (stop.QuadPart - start.QuadPart) * msMultiplier;
}