windows 测试us级别性能的函数

LARGE_INTEGER li1, li2, freq;

::QueryPerformanceFrequency(&freq);
::QueryPerformanceCounter(&li1);


......

::QueryPerformanceCounter(&li2);


Log（"耗时: %I64d/%I64d s", li2.QuadPart - li1.QuadPart, freq.QuadPart);