You need to use the QPC/QPF APIs to get compute the execution time. Invoke the code you want to between calls to QueryPerformanceCounter and then use QueryPerformanceFrequency to convert it from cycles to microseconds.
LARGE_INTEGER nStartTime;
LARGE_INTEGER nStopTime;
LARGE_INTEGER nElapsed;
LARGE_INTEGER nFrequency;
::QueryPerformanceFrequency(&nFrequency);
::QueryPerformanceCounter(&nStartTime);
SomethingToBeTimed();
::QueryPerformanceCounter(&nStopTime);
nElapsed.QuadPart = (nStopTime.QuadPart - nStartTime.QuadPart) * 1000000;
nElapsed.QuadPart /= nFrequency.QuadPart;
References:
http://msdn.microsoft.com/en-us/library/windows/desktop/dn553408(v=vs.85).aspx