C GetTickCount（windows函数）到时间（纳秒）

发布于 2024-09-25 05:50:04 字数 195 浏览 0 评论 0原文

我正在测试同事提供的一段代码，我需要测量一个例程的执行时间，而不是执行（线程）上下文切换。

测量时间的最佳选择是什么？我知道可以使用高分辨率计时器，

QueryPerformanceCounter
QueryPerformanceFrequency

但我如何使用该计时器将其转换为毫秒或纳秒？

原文

I'm testing one code provided from my colleague and I need to measure the time of execution of one routine than performs a context switch (of threads).

What's the best choice to measure the time? I know that is available High Resolution Timers like,

QueryPerformanceCounter
QueryPerformanceFrequency

but how can I translate using that timers to miliseconds or nanoseconds?

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┊风居住的梦幻卍 2024-10-02 05:50:04

LARGE_INTEGER lFreq, lStart;
LARGE_INTEGER lEnd;
double d;

QueryPerformanceFrequency(&lFreq);
QueryPerformanceCounter(&lStart);

/* do something ... */

QueryPerformanceCounter(&lEnd);
d = ((doublel)End.QuadPart - (doublel)lStart.QuadPart) / (doublel)lFreq.QuadPart;

d 是以秒为单位的时间间隔。

LARGE_INTEGER lFreq, lStart;
LARGE_INTEGER lEnd;
double d;

QueryPerformanceFrequency(&lFreq);
QueryPerformanceCounter(&lStart);

/* do something ... */

QueryPerformanceCounter(&lEnd);
d = ((doublel)End.QuadPart - (doublel)lStart.QuadPart) / (doublel)lFreq.QuadPart;

d is time interval in seconds.

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旧城空念 2024-10-02 05:50:04

由于我正在执行的操作约为 500 纳秒，并且计时器没有精度，所以我所做的是，

我使用 GetTickCount() 保存了实际时间 - （使用 ~ 12milis 的精度）并执行路线 N_TIMES （例程执行的次数）比保留，直到我在控制台上按下某些内容。

再次计算时间，将差值除以N_TIMES，类似这样：

int static counter;

无效例程()
{
// 这里的操作..
计数器++；
}
int main(){
开始 <- GetTickCount();
句柄 <- createThread(....., 例程,...);
恢复线程（句柄）；
getchar();
WaitForSingleObject(句柄，无限);
已用时间 = (GetTickCount() - 开始) * 1000000.0) / 计数器；
printf("纳诺数：%d"，已过去);
}

As the operation than i am executing is in order of 500 nanos, and the timers doens't have precision, what i made was,

i saved actual time with GetTickCount() - (Uses precision of ~ 12milis) and performs the execution of a route N_TIMES (Number of times than routine executed) than remains until i press something on console.

Calculate the time again, and make the difference dividing by N_TIMES, something like that:

int static counter;

void routine()
{
// Operations here..
counter++;
}
int main(){
start <- GetTickCount();
handle <- createThread(....., routine,...);
resumeThread(handle);
getchar();
WaitForSingleObject(handle, INFINITE);
Elapsed = (GetTickCount() - start) * 1000000.0) / counter;
printf("Nanos: %d", elapsed);
}