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sim1.c
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sim1.c
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#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <time.h>
#include "sim1.h"
/* delays for a certain number of seconds, does nothing */
int delay(long seconds)
{
time_t t1;
t1 = time(0) + seconds;
while (time(0) < t1)
;
}
void *barista_func(void *sharedQ) {
customer_queue *q = (customer_queue *) sharedQ;
customer *curr_customers[NUM_BARISTAS];
int i;
// get a lock to wait on a barista, then wait for it to be freed
pthread_mutex_lock(&free_baristas_lock);
while (free_baristas == 0)
;
free_baristas--;
pthread_mutex_unlock(&free_baristas_lock);
/* now that we have a pot, figure out which one we can lock
after acquiring a lock, the thread is served and removed from the queue
*/
for (i = 0; i < NUM_BARISTAS; i++) {
if (pthread_mutex_trylock(&baristas[i]) == 0) {
pthread_mutex_lock(&order_queue_lock);
curr_customers[i] = peek_customer(q);
pthread_mutex_unlock(&order_queue_lock);
serve(curr_customers[i]);
pay_func(curr_customers[i]);
gettimeofday(&end_times[curr_customers[i]->id]);
add_customer_time(curr_customers[i]);
// free memory and free pot the customer was at.
free(curr_customers[i]);
free_baristas++;
pthread_mutex_unlock(&baristas[i]);
pthread_exit(NULL);
}
}
}
void add_customer_time(customer *curr_customer) {
if (curr_customer->type)
simple_total += (end_times[curr_customer->id].tv_sec - start_times[curr_customer->id].tv_sec);
else
complex_total += (end_times[curr_customer->id].tv_sec - start_times[curr_customer->id].tv_sec);
}
/* pay the barista */
void pay_func(customer *curr_customer) {
// delay(1);
money_earned = money_earned + curr_customer->cost;
}
int main(int argc, char **argv) {
int i, rc;
int simple_threads = 0;
int complex_threads = 0;
long int totaltime = 0;
pthread_t thr[NUM_THREADS];
/* create a temporary customer */
customer *temp;
struct timeval start, end;
/* create queues */
if ((order_queue = malloc(sizeof(customer_queue))) == NULL)
return EXIT_FAILURE;
/* init locks */
pthread_mutex_init(&order_queue_lock, NULL);
pthread_mutex_init(&free_baristas_lock, NULL);
for (i = 0; i < NUM_BARISTAS; i++)
pthread_mutex_init(&baristas[i], NULL);
gettimeofday(&start, NULL);
srand(time(NULL)); // seed random number generator
for (i = 0; i < NUM_THREADS; ++i) {
/* allocate space for element in queue */
if ((temp = malloc(sizeof(customer))) == NULL)
return EXIT_FAILURE;
temp->id = i;
temp->cost = rand() % 31;
temp->type = temp->cost % 2;
/* customers with type 1 are simple orders
type 0 are complex */
insert_customer(order_queue, temp);
if (temp->type)
simple_threads++;
else
complex_threads++;
gettimeofday(&start_times[i], NULL);
if (rc = pthread_create(&thr[i], NULL, barista_func, (void *)order_queue)) {
printf("FAO:\n");
fprintf(stderr, "error: pthread_create, rc: %d\n", rc);
return EXIT_FAILURE;
}
}
/* block until all threads complete */
for (i = 0; i < NUM_THREADS; ++i) {
pthread_join(thr[i], NULL);
}
gettimeofday(&end, NULL);
totaltime = (end.tv_sec - start.tv_sec);
printf("SIMULATION 1 RESULTS WITH %d THREADS\n", NUM_THREADS);
printf("Complex avg turnaround time: %.01f seconds %d customers\n", (float)complex_total / (float)complex_threads, complex_threads);
printf("Simple avg turnaround time: %.01f seconds %d customers\n", (float)simple_total / (float)simple_threads, simple_threads);
printf("Total time: %lu seconds\n", totaltime);
printf("Money earned: $%d\n", money_earned);
return EXIT_SUCCESS;
}
/* inserts a customer into the given queue, and updates pointers to first/last */
int insert_customer(customer_queue *q, customer *customer) {
if(q->first == NULL) {
q->first = q->last = customer; //if list is empty, first and last = customer
} else {
q->last->next = customer;
q->last = customer; // point "last" pointer to the new node
}
return 0;
}
int is_empty(customer_queue *q) {
if (q->first == NULL)
return 1;
return 0;
}
/* removes the first customer in a queue and updates pointers */
customer* peek_customer(customer_queue *q) {
customer *temp, *old;
old = q->first; // what I want to return AKA current front
if (q->first == q->last) { // only customer in queue
// free(q->first);
q->first = q->last = NULL;
} else {
temp = q->first->next; // new first guy
// free(q->first); // deletes the old first node
q->first = temp; // moves the first pointer to the next item
}
return old; // return success
}
/* "work" function */
void serve(customer *q) {
if (q->type == 0) {
delay(2);
}
else {
delay(1);
}
// printf("Serving customer #%d order cost: %d type: %d\n", q->id, q->cost, q->type);
}