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本帖最后由 20011010wo 于 2016-8-22 22:25 编辑
点击停止后将会计算从上一次点击开始所用的时间，如果没有点击开始……则时间近似为窗口显示的时间 + 校准所用时间(500ms)
32位静态编译Timer.exe
原理:利用某些设备主板上的晶振，开始后将会连续5次校准多核CPU采用QueryPerformanceCounter的问题 QueryPerformanceCounter的运行情况是依赖于CPU的，当CPU是多核时，在某一线程内调用QueryPerformanceCounter，线程会切换于不同的核心之间，这时候QueryPerformanceCounter返回值是不确定的。
多核CPU使用QueryPerformanceCounter 当需要在某一进程中获取时间，需要将该线程绑定在某一固定的核心上，这样获取的高精度计时器才是可靠的。通过SetThreadAffinityMask可以实现这一目的
如:[backcolor=rgb(248, 248, 248)][size=13px]SetThreadAffinityMask(GetCurrentThread(),0x00000001);//绑定当前线程到CPU 1号核心[/size][/backcolor]
附赠高精度时间类(C++)
- class HighAccuracyTimer:private Noncopyable
{
public:
HighAccuracyTimer()
{
succeed = QueryPerformanceFrequency(&freq);
oldMask = SetThreadAffinityMask(GetCurrentThread(), 0x00000001);
QueryPerformanceCounter(&begin);
}
~HighAccuracyTimer()
{
SetThreadAffinityMask(GetCurrentThread(), oldMask);
}
void Start()
{
QueryPerformanceCounter(&begin);
}
void End()
{
QueryPerformanceCounter(&end);
}
__int64 Correct()
{
QueryPerformanceCounter(&correct_begin);
QueryPerformanceCounter(&correct_end);
correct = correct_end.QuadPart - correct_begin.QuadPart;
return correct;
}
unsigned __int64 Count()
{
return (__int64)(end.QuadPart - begin.QuadPart);
}
unsigned __int64 Frequency()
{
return freq.QuadPart;
}
long double Seconds()
{
return (end.QuadPart - begin.QuadPart - correct) / ((long double)freq.QuadPart);
}
long double MillSeconds()
{
return (end.QuadPart - begin.QuadPart - correct) / ((long double)freq.QuadPart) * 1000.0L;
}
long double MicroSeconds()
{
return (end.QuadPart - begin.QuadPart - correct) / ((long double)freq.QuadPart) * 1000000.0L;
}
BOOL succeed;
private:
LARGE_INTEGER freq;
LARGE_INTEGER begin, end, correct_begin, correct_end;
ULONG_PTR oldMask;
__int64 correct = 0LL;
};
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发表于 2016-8-22 21:59:34
发表于 2016-8-24 14:55:59