c获取程序运行时间（纳米级）

#include <stdlib.h>
#include <stdio.h>
#include <time.h>
static unsigned long GetTickCount(){
      struct timespec ts;
      clock_gettime(CLOCK_MONOTONIC, &ts);
      return (ts.tv_sec*1000000 + ts.tv_nsec / 1000);
}

int main(){
      unsigned long t0 = GetTickCount();
    
      // start do your thing
      int i = 0;
      for(i = 0 ; i < 10;i++){
          printf("%d ", i);
      }
      printf("\n");
      //end 
      unsigned long t1 = GetTickCount();
      printf("Cost time:%ld us \n", t1 - t0);
      return 0;
}

或者

#include <stdio.h>
#include <sys/time.h>

int main(){
    struct timeval t_start,t_end;
    long cost_time = 0;

    //get start time
    gettimeofday(&t_start, NULL);
    printf("Start time: %ld us", t_start.tv_usec);
    
    //do something
    printf("-------------------\n");

    //get end time
    gettimeofday(&t_end, NULL);
    printf("End time: %ld us\n", t_end.tv_usec);
    
    //calculate time slot
    cost_time = t_end.tv_usec - t_start.tv_usec;
    printf("Cost time: %ld us", cost_time);
    return 0;
}

static uint64_t GetTickCount() {
  struct timespec ts;
  clock_gettime(CLOCK_MONOTONIC, &ts);
  return (ts.tv_sec * 1000 + ts.tv_nsec / 1000000);
}