Fixing bad performance at school by adding more delay to the death checking loop, Added mutex/semaphore to protect against eating and dying at the same time

1 files changed, 20 insertions, 10 deletions

diff --git a/philo_two/src/routine.c b/philo_two/src/routine.c
index c491a0a..ab01958 100644
--- a/philo_two/src/routine.c
+++ b/philo_two/src/routine.c
@@ -6,7 +6,7 @@
 /*   By: cacharle <marvin@42.fr>                    +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2020/02/14 23:00:07 by cacharle          #+#    #+#             */
-/*   Updated: 2021/01/09 15:17:32 by charles          ###   ########.fr       */
+/*   Updated: 2021/01/10 10:30:04 by cacharle         ###   ########.fr       */
 /*                                                                            */
 /* ************************************************************************** */
 
@@ -28,7 +28,6 @@ void	*routine_philo(t_philo *arg)
 		event_take_fork(arg);
 		event_take_fork(arg);
 		sem_post(arg->conf->sem_grab);
-		arg->time_last_eat = h_time_now();
 		event_eat(arg);
 		if (arg->conf->meal_num != -1 && ++eat_counter == arg->conf->meal_num)
 		{
@@ -45,22 +44,25 @@ void	*routine_philo(t_philo *arg)
 
 void	*routine_death(t_philo *arg)
 {
-	t_time	current;
-
-	current = h_time_now();
-	while (current - arg->time_last_eat < arg->conf->timeout_death)
+	while (true)
 	{
-		current = h_time_now();
-		usleep(1000);
+		sem_wait(arg->sem_eat);
+		if (h_time_now() - arg->time_last_eat > arg->conf->timeout_death)
+			break ;
+		sem_post(arg->sem_eat);
+		usleep(2000);
 	}
 	event_die(arg);
 	return (NULL);
 }
 
+#define PHILO_SEM_EAT_PREFIX "semaphore_philo_two_eat_"
+
 t_philo	*routine_create_philos(t_philo_conf *conf)
 {
-	int		i;
-	t_philo	*philos;
+	long int	i;
+	t_philo		*philos;
+	const char	*name;
 
 	if ((philos = malloc(sizeof(t_philo) * conf->philo_num)) == NULL)
 		return (NULL);
@@ -69,6 +71,14 @@ t_philo	*routine_create_philos(t_philo_conf *conf)
 	{
 		philos[i].id = i + 1;
 		philos[i].conf = conf;
+		name = philo_sem_eat_name(PHILO_SEM_EAT_PREFIX, philos[i].id);
+		sem_unlink(name);
+		philos[i].sem_eat = sem_open(name, O_CREAT | O_EXCL, 0700, 1);
+		if (philos[i].sem_eat == SEM_FAILED)
+		{
+			free(philos);
+			return (NULL);
+		}
 	}
 	return (philos);
 }