Windows下 C++测量时间的函数 精度为可以到100us级别

class RecordTimer
{
public:
	RecordTimer();
	~RecordTimer();

	void start();
	void end();
	double getTick();

private:
	LARGE_INTEGER m_frequency;
	LARGE_INTEGER m_startTime;
	LARGE_INTEGER m_endTime;
};

RecordTimer::RecordTimer()
{
	QueryPerformanceFrequency(&m_frequency);
}


RecordTimer::~RecordTimer()
{
}

void RecordTimer::start()
{
	QueryPerformanceCounter(&m_startTime);
}

void RecordTimer::end()
{
	QueryPerformanceCounter(&m_endTime);
}

double RecordTimer::getTick()
{
	return (double)(m_endTime.QuadPart - m_startTime.QuadPart)*1.0 / m_frequency.QuadPart * 1000;
}