Delay Calculatin of Packet Sending Loop

I want to calculate the total some of delay pf receiving Side Packet .
Code is as Follow ..
What is weired that even if i invoke a sleep of 2 sec ,than its show delay alwts zero. Delay will be in microsec ..Is there any problem with logic or anyhting else..

Code:

---

do
{

#pragma omp parallel private(nthreads, tid)
 {

  /* Obtain thread number */
  tid = omp_get_thread_num();
  if (tid == 0)

  {
    nthreads = omp_get_num_threads();
    printf("Number of threads = %d\n", nthreads);
    }
   
    #pragma omp critical
    { 
          gettimeofday(&tv3,NULL);
            if(flag==0)
          Cur_Pkt_Time=tv3.tv_sec+tv3.tv_usec;
          else
       
          {
              Las_Pkt_Time= Cur_Pkt_Time ;
              Cur_Pkt_Time=tv3.tv_sec+tv3.tv_usec;
              sleep(2);
              Delay=Delay+(Cur_Pkt_Time-Las_Pkt_Time);
          }
          flag=1;           
          n = write(sockfd,buffer,packet_size);                 
          num_pkt_send++;
          TotalSend=TotalSend+n;
    }
    if (n < 0)
    {
        error("ERROR writing to socket");
          exit(1);
    }
    printf("%d Bytes Send: %d\n",num_pkt_send,n);
   
    }
    gettimeofday(&tv2, NULL);
} while((tv2.tv_sec-tv1.tv_sec)<=Sen_Loop_time);

---

Code:

---

Cur_Pkt_Time=tv3.tv_sec+tv3.tv_usec;

---

This is incorrect. Think about what you are doing here: you are treating a microsecond the same as a second. A common way to generate integer based timestamps is to do something like this instead:

Code:

---

Cur_Pkt_Time=tv3.tv_sec*1000000ul+tv3.tv_usec;

---

Now Cur_Pkt_Time is a timestamp in microseconds. Make sure that Cur_Pkt_Time is a type that can hold very large integers.

I tried by following modification in code .but instead of giving delay ,its giving total Loop run time which is not expected

Code:

---

while(n>0)
{
    n = read(newsockfd,buffer,packet_size);
    if(n<packet_size)
    overhead++;
          gettimeofday(&tv3,NULL);
            if(flag==0)
          Las_Pkt_Time=tv3.tv_sec*1000000ul+tv3.tv_usec;
          else
       
          {
             
              Cur_Pkt_Time=tv3.tv_sec*1000000ul+tv3.tv_usec;
              Delay=Delay+(Cur_Pkt_Time-Las_Pkt_Time);
              Las_Pkt_Time= Cur_Pkt_Time ;
              //sleep(2);
             
          }
          flag=1;
    TotalRecv=TotalRecv+n;
    num_pkt_rec++;
    printf("%d Bytes Received: %d\n",num_pkt_rec ,n);     

}

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