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#define NUM_ARGS 0
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <dirent.h>
#include <string.h>
#include <time.h>
#include <pthread.h>
#include <semaphore.h>
#include<sys/time.h>
long semTotal = 0;
struct buffer {
int vals[100];
int index;
};
struct semBuffer {
struct buffer* q;
sem_t* psem;
sem_t* csem;
pthread_mutex_t* mutex;
};
void insert(struct buffer* q, int val) {
q->vals[q->index] = val;
++q->index;
}
int delete(struct buffer* q) {
--q->index;
int val = q->vals[q->index];
return val;
}
// TODO: Insert code to use a semaphore.
void* semProducer(void* arg) {
// Random delay. DO NOT REMOVE!
usleep(rand() % 1000);
struct semBuffer* sq = (struct semBuffer*) arg;
sem_wait(sq->psem);
pthread_mutex_lock(sq->mutex);
static int in = 0;
++in;
// Add an element to the queue.
insert(sq->q, in);
pthread_mutex_unlock(sq->mutex);
sem_post(sq->csem);
}
// TODO: Insert code to use a semaphore.
void* semConsumer(void* arg) {
// Random delay. DO NOT REMOVE!
usleep(rand() % 1000);
struct semBuffer* sq = (struct semBuffer*) arg;
sem_wait(sq->csem);
pthread_mutex_lock(sq->mutex);
// Reove an element from the queue.
semTotal += delete(sq->q);
pthread_mutex_unlock(sq->mutex);
sem_post(sq->psem);
}
int main(int argc, char** argv) {
if (argc != NUM_ARGS + 1) {
printf("Wrong number of args, expected %d, given %d\n", NUM_ARGS, argc - 1);
exit(1);
}
// Seed the random generator.
srand(time(NULL));
// Create threads.
pthread_t semPool[100];
struct timeval start;
gettimeofday(&start, NULL);
// Create task queue.
struct semBuffer* sq = (struct semBuffer*) malloc(sizeof(struct semBuffer));
sq->q = (struct buffer*) malloc(sizeof(struct buffer));
sq->q->index=0;
sq->psem = (sem_t*) malloc(sizeof(sem_t));
sq->csem = (sem_t*) malloc(sizeof(sem_t));
sq->mutex = (pthread_mutex_t*) malloc(sizeof(pthread_mutex_t));
// TODO: Initilaize semaphores
sem_init(sq->psem, 0, 50);
sem_init(sq->csem, 0, 0);
pthread_mutex_init(sq->mutex, NULL);
for (int i=0; i < 50; ++i) {
pthread_create(&semPool[i], NULL, semProducer, (void*) sq);
pthread_create(&semPool[50 + i], NULL, semConsumer, (void*) sq);
}
for (int i=0; i < 100; ++i) pthread_join(semPool[i], NULL);
struct timeval end;
gettimeofday(&end, NULL);
printf("Sem Test: \nTotal of buffer = %ld\n", semTotal);
printf("Time (in us) to complete = %ld\n", ((end.tv_sec - start.tv_sec) * 1000000) + (end.tv_usec - start.tv_usec));
}
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