Mesure de code

   //Source: http://www.cplusplus.com/ref/ctime/difftime.html
   #include <stdio.h>
   #include <time.h>

   int main ()
   {
     time_t start,end;
     char szInput [256];
     double dif;

     time (&start);
     printf ("Please, enter your name: ");
     gets (szInput);
     time (&end);
     dif = difftime (end,start);
     printf ("Hi %s.\n", szInput);
     printf ("You have taken %.2lf seconds to type your name.\n", dif );
 
     return 0;
   }

  //Source: http://c.developpez.com/sources/c/?page=IIIDATE_calcul_temps_execution
  #include <stdio.h>
  #include <time.h>

  int main (void)
  {
    clock_t start, end;

    start = clock ();
    {
      /* Portion de code a chronometrer */
    }
    end = clock ();
    printf ("Temps en secondes : %f\n", (end - start) / (double)CLOCKS_PER_SEC);
    return 0;
  }

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

  int main()
  {
    time_t depart, fin;
    double duree;

    depart = clock();
    // code à mesurer
    fin = clock();

    duree = (double)(fin-depart)/CLOCKS_PER_SEC;

    printf("Durée: %.2lf\n", duree);
    return 0;
}

  //Source: Bert
  #include <stdio.h>
  #include <windows.h>

  int main()
  {
    long depart=0, fin=0; duree=0;

    depart = GetTickCount();
    // Code à mesurer
    fin = GetTickCount();

    duree = fin - depart;
    // En divisant par mille, obtient également le nombre de secondes
    printf("durée: %ld ms soit %ld secondes\n", duree, duree/1000);

    return 0;
  }

  //Source: Bert
  #include <stdio.h>
  #include <time.h>
  #include <windows.h>

  int main()
  {
    SYSTEMTIME st;
    GetLocalTime(&st);
    char szBuf[284];
    LPCSTR lpEvent="evenement";
    wsprintf(szBuf,"%02d:%02d:%02d.%03dms\t%s",
       st.wHour, st.wMinute, st.wSecond, st.wMilliseconds, lpEvent);
    puts(szBuf); //affiche 13:24:36.640ms evenement

    getchar();
    return 0;
  }

  //source: http://souptonuts.sourceforge.net/code/getrusage.cc.html
  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <sys/time.h>
  #include <sys/resource.h>

  int main(int argc, char **argv)
  {
      struct rusage buf;

      if(argc == 2) {
        system(argv[1]);
      }else {
        fprintf(stderr,"./getrusage  \"ls -l >/dev/null\"\n");
        exit(0);
      }
      int err = getrusage(RUSAGE_CHILDREN, &buf);
      //int err = getrusage(RUSAGE_SELF, &buf);
      printf("ERR=%d\n", err);
      printf("%20s:%ld/%ld\t%s\n",
  	     "ru_utime",
  	     buf.ru_utime.tv_sec,
  	     buf.ru_utime.tv_usec,
  	     "user time used (secs/usecs)");
      printf("%20s:%ld/%ld\t%s\n",
  	     "ru_stime",
	     buf.ru_stime.tv_sec,
	     buf.ru_stime.tv_usec,
	     "system time used (secs/usecs)");
      printf("%20s:%-10ld\t%s\n", 
	     "ru_maxrss",
	     buf.ru_maxrss,
	     "maximum resident set size");
      printf("%20s:%-10ld\t%s\n",
	     "ru_ixrss", 
	     buf.ru_ixrss,
	     "integral shared memory size");
      printf("%20s:%-10ld\t%s\n",
	     "ru_idrss",
	     buf.ru_idrss,
	     "integral unshared data size");
      printf("%20s:%-10ld\t%s\n", 
	     "ru_isrss",
	     buf.ru_isrss,
	     "integral unshared data stack size");
      printf("%20s:%-10ld\t%s\n", 
	     "ru_minflt",
	     buf.ru_minflt,
	     "page reclaims");
      printf("%20s:%-10ld\t%s\n",
	     "ru_majflt",
	     buf.ru_majflt,
	     "page faults");
      printf("%20s:%-10ld\t%s\n",
	     "ru_nswap",
	     buf.ru_nswap,
	     "swaps");
      printf("%20s:%-10ld\t%s\n",
	     "ru_inblock",
	     buf.ru_inblock,
	     "block input operations");
      printf("%20s:%-10ld\t%s\n",
	     "ru_oublock",
	     buf.ru_oublock,
	     "block output operations");
      printf("%20s:%-10ld\t%s\n",
	     "ru_msgsnd",
	     buf.ru_msgsnd,
	     "messages sent");
      printf("%20s:%-10ld\t%s\n",
	     "ru_msgrcv",
	     buf.ru_msgrcv,
	     "messages received");
      printf("%20s:%-10ld\t%s\n",
	     "ru_nsignals",
	     buf.ru_nsignals,
	     "signals received");
      printf("%20s:%-10ld\t%s\n",
	     "ru_nvcsw",
	     buf.ru_nvcsw,
	     "voluntary context switches");
      printf("%20s:%-10ld\t%s\n",
	     "ru_nivcsw",
	     buf.ru_nivcsw,
	     "involuntary context switches");
    exit(0);
  }

  //Source: Bert
  #include <stdio.h>
  #include <windows.h>

  int main()
  {
    LARGE_INTEGER freq, depart, fin;
    double duree=0;
    QueryPerformanceFrequency(&freq); // Obtient fréquence

    QueryPerformanceCounter(&depart);
    // Code à mesurer
    QueryPerformanceCounter(&fin);

    duree = ((fin.QuadPart-depart.QuadPart)/(double)freq.QuadPart)*1000L;
    printf("Durée: %.4lf millisecondes\n", duree);

    return 0;
  }

  //Source: Bert
  #include <stdio.h>
  #include <sys/time.h>

  int main()
  {
    struct timeval depart, fin;
    struct timezone tz;
    long duree=0;

    gettimeofday(&depart, &tz);
    // code à mesurer
    gettimeofday(&fin, &tz);

    duree=(fin.tv_sec-depart.tv_sec) * 1000000L + (fin.tv_usec-depart.tv_usec);  
    printf("Durée: %ld microsecondes\n", duree);

    return 0;
  }

    tv_sec contient le nombre de secondes.
    tv_usec contient le nb de microsecondes de la dernière seconde.
    Par conséquent on calcule les différences de secondes et microsecondes entre fin et depart,
    multiplie le nombre de secondes par 10^6 pour obtenir des microsecondes,
    et lui ajoute les microsecondes restantes pour avoir la durée en microsecondes.