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parent and child process question?


 
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Question parent and child process question?

Hi everybody,

I'm trying to understand how a parent and child processes interact.

This function( below) basically measures the fork time from the perspective of the parent only.

what i would like to know is how to measure the time from the perspective of parent and child (ie: inserting the GETTIME(endt) inside the child).
Any help would be appreciated.

HTML Code:
void run_tests(int nt)
{
  struct timeval begt;
  struct timeval endt;

  double secs;
  int i;
  pid_t pid;
  int waitid;
  int status;

  double max_secs = 0.000000;
  double min_secs = 0.000000;
  double average  = 0.000000;
  double sum      = 0.000000;

  for(i=0; i<nt; i++)
  {
    GETTIME(begt);  // gettimeofday()

    if((pid = fork()) < 0)
    {
     perror("fork() failed!\n");
     _exit(1);
    }
    if( pid == 0)
    {
     _exit(0);
    }
    waitid = wait(&status);
    GETTIME(endt);  // gettimeofday()

    secs = TOTALSECS(begt,endt);
    max_secs = max(secs,max_secs);
    min_secs = min(secs,min_secs);

    sum += secs;

   printf("%2d: secs = %.6f\n", i,secs);
  }    /* end of FOR loop */

  average = sum / (i + 1);

  printf("min:     %.6f\n", min_secs);
  printf("max:     %.6f\n", max_secs);
  printf("sum:     %.6f\n", sum);
  printf("average: %.6f\n", average);
  printf("waitid: %d \n", waitid);
  printf(" \n");

}

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