高精度计时器QueryPerformanceCounter正确的打开方式（windows环境下）

HANDLE thread = GetCurrentThread();

// Set affinity to the first core
DWORD_PTR oldMask = SetThreadAffinityMask(thread, GTimerMask );

// Query the timer
QueryPerformanceCounter(&mStartTime);
mStartTick = GetTickCount();

// Reset affinity
SetThreadAffinityMask(thread, oldMask);

void appResetTimerMask()

{

// Get the current process core mask

ULONG_PTR proMask;

ULONG_PTR sysMask;

GetProcessAffinityMask(GetCurrentProcess(), &procMask, &sysMask);


// If procMask is 0, consider there is only one core available

// (using 0 as procMask will cause an infinite loop below)

if (procMask == 0)

     procMask = 1;


// Find the lowest core that this process uses

      if (GTimerMask == 0)

      {

          GTimeMask = 1;

          while ((GTimerMask & procMask) == 0)

          {

              GTimerMask <<= 1;

          }

      }

}

inline DOUBLE appSeconds()

{
	LARGE_INTEGER Cycles;

	HANDLE thread = NULL;

	ULONG_PTR oldMask = 0;


	if (GEnableTimerAffinityMask)      //GEnableTimerAffinityMask为TRUE时需要将线程绑定到固定核心
	{

		thread = GetCurrentThread();


		if (GTimerMask == 0)       //GTimerMask默认值为0

		{

			appResetTimerMask();

		}


		oldMask = SetThreadAffinityMask(thread, GTimerMask);

	}

	QueryPerformanceCounter(&Cycles);

	if (GEnableTimerAffinityMask)

	{

		SetThreadAffinityMask(thread, oldMask);

	}


	return Cycles.QuadPart * GSecondsPerCycle + 16777216.0;

}