用QueryPerformanceFrequency 和 QueryPerformanceCounter 进行高精度计时

void main() {
LARGE_INTEGER lv;

// 获取每秒多少CPU Performance Tick
QueryPerformanceFrequency( &lv );

// 转换为每个Tick多少秒
double secondsPerTick = 1.0 / lv.QuadPart;

for ( size_t i = 0; i < 100; ++i ) {
// 获取CPU运行到现在的Tick数
QueryPerformanceCounter( &lv );

// 计算CPU运行到现在的时间
// 比GetTickCount和timeGetTime更加精确
double timeElapsedTotal = secondsPerTick * lv.QuadPart;

cout.precision( 6 );
cout << fixed << showpoint << timeElapsedTotal << endl;
//printf( "%lf \n", timeElapsedTotal ) ;
}
}
http://www.cppblog.com/bidepan2023/archive/2008/01/22/41627.html