timeval中使用结构 [英] Timeval struct usage

问题描述

我需要计算需要运行某些功能时，冲进以下code，记录和放大器;输出纳秒一张code的执行时间

和也有

之间的差异

timeval结构timer_spent ＆安培; 的timeval timer_spent

  / *把这一行在文件的顶部：* /
＃包括LT＆; SYS / time.h中＆GT;/ *将这个权，你要的时间code面前：* /
timeval结构timer_start，timer_end;
函数gettimeofday（安培; timer_start，NULL）;/ * C要的时间将这个权利的$ C $后：* /
函数gettimeofday（安培; timer_end，NULL）;
双timer_spent = timer_end.tv_sec  -  timer_start.tv_sec +（timer_end.tv_usec  -  timer_start.tv_usec）;
的printf（花费时间：％.6f \\ n，timer_spent）/1000000.0;
 

但我需要在纳秒precise时机。我已经了解的timeval结构没有完整的想法。

所以好心帮我家伙.. !!

解决方案

  

但我需要在纳秒precise时机。

然后用

  INT clock_gettime（clockid_t clk_id，结构的timespec * TP）;
 

它返回的时间以秒和纳秒

 结构的timespec {
  time_t的tv_sec; / *秒*的/
  长tv_nsec; / * *纳秒/
};
 

相关链接：

• http://linux.die.net/man/3/clock_gettime

clock_getres的
• 使用 - 新手Linux下C

I needed to calculate the time it takes to run a certain function and ran into the following code,record & output the execution time of a piece of code in nanoseconds

And also is there any difference between

struct timeval timer_spent & timeval timer_spent

/* Put this line at the top of the file: */
#include <sys/time.h>

/* Put this right before the code you want to time: */
struct timeval timer_start, timer_end;
gettimeofday(&timer_start, NULL);

/* Put this right after the code you want to time: */
gettimeofday(&timer_end, NULL);
double timer_spent = timer_end.tv_sec - timer_start.tv_sec + (timer_end.tv_usec - timer_start.tv_usec);
printf("Time spent: %.6f\n", timer_spent)/1000000.0;

But I need the precise timing in nanoseconds. I've no complete idea about the timeval struct.

So kindly help me guys.. !!

解决方案

But I need the precise timing in nanoseconds.

Then use

int clock_gettime(clockid_t clk_id, struct timespec *tp);

It returns time in seconds and nanoseconds

struct timespec {
  time_t   tv_sec;        /* seconds */
  long     tv_nsec;       /* nanoseconds */
};

Useful links:

• http://linux.die.net/man/3/clock_gettime
• Use of clock_getres - newbie Linux C

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