static volatile LONG last_thread_switch_delta = 0;
void __cdecl thread_func(void *)
{
    static volatile LONG last_thread_id = 0;
    static volatile LONG last_thread_switch = 0;
    for (LONG self_thread_id = ::GetCurrentThreadId();;)
    {
        if (::InterlockedExchange(&last_thread_id, self_thread_id)!=self_thread_id)
        {
            LONG ticks = (LONG)::GetTickCount();
            LONG prev = ::InterlockedExchange(&last_thread_switch, ticks);
            ::InterlockedExchange(&last_thread_switch_delta, (DWORD)ticks - (DWORD)prev);
        }
    }    
}

void common(HDC dc)
{
    ::SetProcessAffinityMask(::GetCurrentProcess(), 1);
    timeBeginPeriod(1);
    _beginthread(thread_func, 0, 0);
    _beginthread(thread_func, 0, 0);
    char txt[0x100];
    for(;;)
    {
        ::Sleep(1000);
        if (dc)
        {
            int n = sprintf(txt, "last_thread_switch_delta=%u msec   ", last_thread_switch_delta);
            ::TextOutA(dc, 0, 0, txt, n);
            MSG m;
            while (::PeekMessage(&m, 0, 0, 0, PM_REMOVE))
            {
                ::DispatchMessage(&m);
            }
        }
        else
            printf("last_thread_switch_delta=%u msec   \r", last_thread_switch_delta);
    }

}

void wmain(int argc, wchar_t **argv)
{
    common(0);
}

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
    HWND wnd = ::CreateWindow(TEXT("STATIC"), TEXT(""), WS_POPUP|WS_VISIBLE, 0, 0, 400, 100, 0, 0, 0, 0);
    HDC dc = ::GetDC(wnd);
    common(dc);
}