An implementation/solution to Dijkstra's dining philosophers problem for 42 School Lisboa. A table of philosophers each have a fork/chopstick between them and a bowl of spaghetti in the middle of the table. For a philosopher to eat, they must take both the fork to their left and the the fork to their right.
Each philosopher is a thread and each fork is protected by a mutex. Deadlocks, data races and philosopher deaths must be avoided wherever possible. There is no communication between philosophers but there is a monitor/waiter thread that can report if philosophers have died.
Git clone the repository:
https://github.com/TimHopg/Dining-Philosophers.gitRun make from within the directory.
make clean will remove object files.
make fclean will remove program and object files.
./philo [number_of_philos] [time_to_die] [time_to_eat] [time_to_sleep] [number_of_required_meals]philo takes 4 mandatory arguments and one optional.
number_of_philosophers - Any number between 1 and 200.
time_to_die - The time in milliseconds for a philosopher to die since the beginning of their last meal. Must be > 60.
time_to_eat - The time in milliseconds that it takes for each philosopher to finish their meal.
time_to_sleep - The time in milliseconds that each philosopher will sleep for before they can eat again.
number_of_required_meals is optional.
Because performance was paramount for this project and input limits were known, the program is implemented entirely on the stack (excluding standard mutex implementation which creates some heap allocation by default).
This means that margins of error could be kept lower.
Each philosopher around the table is a thread and one additional thread, the monitor, oversees the operations.
Each fork is a mutex itself (rather than protecting a variable which represents the fork).
To help mitigate deadlocks, odd number philosophers always take the fork on their left first and even philosophers always take the fork on their right.
Data races were avoided by ensuring any variables that are accessed by more than one thread are protected by a mutex.
Environment pointer. The third argument to main() after argc and argv. envp points to the environment variables of the current user. This is a null-terminated array of null-terminated strings.