Linux下测试函数运行时间（ns级或s级）

添加头文件

#include <time.h>

1. 函数起始处添加以下代码

timespec time1, time2;
clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &time1);

2.函数结尾处添加以下代码

clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &time2);
printf("ProcessTime:%ld \n", diff(time1, time2).tv_nsec);

3.diff函数声明

timespec diff(timespec start, timespec end);

4：diff函数定义

timespec diff(timespec start, timespec end)
{
	timespec temp;
	if ((end.tv_nsec - start.tv_nsec) < 0) {
		temp.tv_sec = end.tv_sec - start.tv_sec - 1;
		temp.tv_nsec = 1000000000 + end.tv_nsec - start.tv_nsec;
	}
	else {
		temp.tv_sec = end.tv_sec - start.tv_sec;
		temp.tv_nsec = end.tv_nsec - start.tv_nsec;
	}
	return temp;
}

5:参考博客
https://blog.youkuaiyun.com/yusiguyuan/article/details/18231135