//====================================================== file = md1_500.c =====
//=  A CSIM simulation of an M/D/1 queueing system                            =
//=   - Tallies over 500 ms response time jobs                                =
//=============================================================================
//=  Notes: 1) Values for lambda and mu are set in the main program           =
//=---------------------------------------------------------------------------=
//=  Example execution:                                                       =
//=                                                                           =
//=   =============================================================           =
//=   ==     *** CSIM M/D/1 queueing system simulation ***       ==           =
//=   =============================================================           =
//=   = Lambda   = 1.245000 cust/sec                                          =
//=   = Mu       = 5.000000 cust/sec                                          =
//=   =============================================================           =
//=   = Total CPU time     = 3.135000 sec                                     =
//=   = Total sim time     = 2579604.750945 sec                               =
//=   = Total completions  = 3211059 cust                                     =
//=   =------------------------------------------------------------           =
//=   = >>> Simulation results                                    -           =
//=   =------------------------------------------------------------           =
//=   = Utilization        = 24.895736 %                                      =
//=   = Mean num in system = 0.290157 cust                                    =
//=   = Mean response time = 0.233098 sec                                     =
//=   = Mean service time  = 0.200000 sec                                     =
//=   = Mean throughput    = 1.244787 cust/sec                                =
//=   = Percent over 500ms = 1.476616 %                                       =
//=   =============================================================           =
//=---------------------------------------------------------------------------=
//=  Build: standard CSIM build                                               =
//=---------------------------------------------------------------------------=
//=  Execute: md1_500                                                         =
//=---------------------------------------------------------------------------=
//=  Author: Ken Christensen                                                  =
//=          University of South Florida                                      =
//=          WWW: http://www.csee.usf.edu/~christen                           =
//=          Email: christen@csee.usf.edu                                     =
//=---------------------------------------------------------------------------=
//=  History: KJC (07/10/13) - Genesis                                        =
//=           KJC (07/14/13) - Clean-up and modified to run for NUM_JOBS      =
//=============================================================================
//----- Includes --------------------------------------------------------------
#include <stdio.h>      // Needed for printf()
#include "csim.h"       // Needed for CSIM stuff

//----- Defines ---------------------------------------------------------------
#define NUM_JOB 3211058 // Number of jobs to simulate

//----- Globals ---------------------------------------------------------------
FACILITY Server;        // Declaration of CSIM Server facility
EVENT    DoneEvent;     // Done event
int      OverCount;     // Over 500ms counter

//----- Prototypes ------------------------------------------------------------
void generate(double lambda, double mu);            // Customer generator
void queue1(double service_time, double org_time);  // Single server queue

//=============================================================================
//==  Main program                                                           ==
//=============================================================================
void sim(void)
{
  double   lambda;      // Mean arrival rate (cust/sec)
  double   mu;          // Mean service rate (cust/sec)

  // Create the simulation
  create("sim");

  // CSIM and other initializations
  Server = facility("Server");
  DoneEvent = event("Done event");
  OverCount = 0;

  // Parameter initializations (per project statement)
  lambda = 1.245;
  mu = 5.0;

  // Initiate generate function and hold for SIM_TIME
  generate(lambda, mu);
  wait(DoneEvent);

  // Output results
  printf("============================================================= \n");
  printf("==     *** CSIM M/D/1 queueing system simulation ***       == \n");
  printf("============================================================= \n");
  printf("= Lambda   = %f cust/sec   \n", lambda);
  printf("= Mu       = %f cust/sec   \n", mu);
  printf("============================================================= \n");
  printf("= Total CPU time     = %f sec      \n", cputime());
  printf("= Total sim time     = %f sec      \n", clock);
  printf("= Total completions  = %d cust     \n", completions(Server));
  printf("=------------------------------------------------------------ \n");
  printf("= >>> Simulation results                                    - \n");
  printf("=------------------------------------------------------------ \n");
  printf("= Utilization        = %f %%       \n", 100.0 * util(Server));
  printf("= Mean num in system = %f cust     \n", qlen(Server));
  printf("= Mean response time = %f sec      \n", resp(Server));
  printf("= Mean service time  = %f sec      \n", serv(Server));
  printf("= Mean throughput    = %f cust/sec \n", tput(Server));
  printf("= Percent over 500ms = %f %%       \n",
    100.0 * OverCount / completions(Server));
  printf("============================================================= \n");
}

//=============================================================================
//==  Function to generate Poisson customers                                 ==
//=============================================================================
void generate(double lambda, double mu)
{
  double   interarrival_time;    // Interarrival time to next send
  double   service_time;         // Service time for this customer

  create("generate");

  // Loop forever to create jobs
  while(1)
  {
    // Pull an interarrival time and hold for it
    interarrival_time = exponential(1.0 / lambda);
    hold(interarrival_time);

    // Pull a service time and then send the customer to the queue
    service_time = 1.0 / mu;
    queue1(service_time, clock);
  }
}

//=============================================================================
//==  Function for single server queue                                       ==
//=============================================================================
void queue1(double service_time, double org_time)
{
  create("queue1");

  // Reserve, hold, and release server
  reserve(Server);
  hold(service_time);
  release(Server);

  // Tally response times over 500 ms
  if ((clock - org_time) > 0.500)
    OverCount++;

  // If completions is NUM_JOB then set done event
  if (completions(Server) >= NUM_JOB)
    set(DoneEvent);
}