获取运行时间GetSystemTimeAsFileTime QueryPerformanceCounter

之前一直用 QueryPerformanceFrequency , QueryPerformanceCounter发现系统调用时间比较长.

改用 GetSystemTimeAsFileTime

 

新的:

#include <Windows.h>

class TimeStamp
{
    static FILETIME __startFileTime,__endFileTime;
    static ULARGE_INTEGER __startTime , __endTime;

public:
    static void start() {
        GetSystemTimeAsFileTime(&__startFileTime);
        __startTime.LowPart = __startFileTime.dwLowDateTime;
        __startTime.HighPart = __startFileTime.dwHighDateTime;
    }
    static unsigned __int64 elapsed() {
        GetSystemTimeAsFileTime(&__endFileTime);
        __endTime.LowPart = __endFileTime.dwLowDateTime;
        __endTime.HighPart = __endFileTime.dwHighDateTime;
        return (__endTime.QuadPart - __startTime.QuadPart) / 10000; // ms

    }
};
ULARGE_INTEGER TimeStamp::__endTime = {0};
ULARGE_INTEGER TimeStamp::__startTime = {0};
FILETIME TimeStamp::__endFileTime = {0};
FILETIME TimeSt