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, 14 insertions, 9 deletions

diff --git a/philo_three/src/child.c b/philo_three/src/child.c
index 641b82d..63ec3e4 100644
--- a/philo_three/src/child.c
+++ b/philo_three/src/child.c
@@ -6,7 +6,7 @@
 /*   By: cacharle <me@cacharle.xyz>                 +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2020/09/30 14:36:16 by cacharle          #+#    #+#             */
-/*   Updated: 2021/01/09 15:59:00 by charles          ###   ########.fr       */
+/*   Updated: 2021/01/10 10:39:19 by cacharle         ###   ########.fr       */
 /*                                                                            */
 /* ************************************************************************** */
 
@@ -14,13 +14,13 @@
 
 void	*routine_death(t_philo *philo)
 {
-	t_time	current;
-
-	current = h_time_now();
-	while (current - philo->time_last_eat < philo->conf->timeout_death)
+	while (true)
 	{
-		current = h_time_now();
-		usleep(1000);
+		sem_wait(philo->sem_eat);
+		if (h_time_now() - philo->time_last_eat > philo->conf->timeout_death)
+			break ;
+		sem_post(philo->sem_eat);
+		usleep(2000);
 	}
 	event_die(philo);
 	return (NULL);
@@ -37,7 +37,6 @@ void	st_child_loop(t_philo *philo)
 		event_take_fork(philo);
 		event_take_fork(philo);
 		sem_post(philo->sem_grab);
-		philo->time_last_eat = h_time_now();
 		event_eat(philo);
 		eat_counter++;
 		if (philo->conf->meal_num != -1 && eat_counter == philo->conf->meal_num)
@@ -51,10 +50,13 @@ void	st_child_loop(t_philo *philo)
 	}
 }
 
+#define PHILO_SEM_EAT_PREFIX "semaphore_philo_three_eat_"
+
 pid_t	child_start(t_philo *philo)
 {
 	pthread_t	thread_death;
 	pid_t		pid;
+	const char	*sem_eat_name;
 
 	if ((pid = fork()) == -1)
 		return (-1);
@@ -66,10 +68,13 @@ pid_t	child_start(t_philo *philo)
 		philo->sem_meal_num = sem_open(PHILO_SEM_MEAL_NUM_NAME, 0);
 		philo->sem_start = sem_open(PHILO_SEM_START_NAME, 0);
 		philo->sem_grab = sem_open(PHILO_SEM_GRAB_NAME, 0);
+		sem_eat_name = philo_sem_eat_name(PHILO_SEM_EAT_PREFIX, philo->id);
+		sem_unlink(sem_eat_name);
+		philo->sem_eat = sem_open(sem_eat_name, O_CREAT | O_EXCL, 0700, 1);
+		sem_wait(philo->sem_start);
 		philo->time_last_eat = h_time_now();
 		pthread_create(&thread_death, NULL, (t_routine)routine_death, philo);
 		pthread_detach(thread_death);
-		sem_wait(philo->sem_start);
 		st_child_loop(philo);
 		exit(0);
 	}