SmartSpinMutex mtx;
SpinMutex sm;
CRITICAL_SECTION cs;
long cnt = 0;
DWORD WINAPI Entry(void *)
{
    bool first = _InterlockedIncrement(&cnt) == 1;
    while(1)
    {
        //mtx.Lock();
        //sm.Lock();
        EnterCriticalSection(&cs);

        if (!first)    Sleep(1);    
        _InterlockedIncrement(&cnt);

        LeaveCriticalSection(&cs);
        //mtx.Unlock();
        //sm.Unlock();
        if (!first)    Sleep(10);
    }
}

class SmartSpinMutex
{
public:
    SmartSpinMutex() : pEvent(&g_Event), m_lock(0) {}
    void Lock() 
    { 
        for (__int64 index = pEvent->BeginWait(); 
            ::_InterlockedIncrement(&m_lock) > 1; 
            index = pEvent->BeginWait())
        {
            pEvent->PerformWait(index, INFINITE);
        }
    }
    void Unlock()
    {
        if (::_InterlockedExchange(&m_lock, 0) != 1)
            pEvent->Pulse();
    }
private:
    static PulsarEvent g_Event;
    PulsarEvent * pEvent;
    long m_lock;
};
DECLSPEC_SELECTANY PulsarEvent SmartSpinMutex::g_Event;

class SpinMutex
{
public:
    SpinMutex() : m_lock(0) {}
    void Lock() 
    { 
        while (_InterlockedCompareExchange(&m_lock, 1, 0))
            SwitchToThread();
    }
    void Unlock()
    {
        _InterlockedExchange(&m_lock, 0);
    }
private:
    long m_lock;
};