format pour rendu

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Hugo LAMY
2022-01-26 15:37:17 +01:00
parent b192efa4a9
commit 6d3280631c
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options :
```
- n_phi -> number_of_philosophers
- t_die -> time_to_die
- t_eat -> time_to_eat
- t_slp -> time_to_sleep
- n_eat -> [number_of_times_each_philosopher_must_eat]
```
**thread :**
- parts of a process that performs code simultaneously
- thread are light-weight-process (LWP) that happens inside a process (observe with command `ps -eLf`)
- a process can be single-threaded or multi-threaded
- different process have a different PID and different LWP, different thread in the same process have the same PID and different LWP
- thread vs process :
*process :*
- process is isolated, it doesn't share memory with any other process
- process is less efficient in communication, it takes more times to create or terminate or switch
- process speed is not impacted by speed of other process (untill it reach the limit of cpu)
*thread :*
- thread are not isolated, they share memory with the other threads
- thread is more efficient in communication, it takes less times to create or terminate or switch
- thread can become slow if the process does many concurrent tasks
- ressources :
- https://www.baeldung.com/linux/process-vs-thread
**mutex :**
- mutual exclusion
- to prevent a part of the code to be performed simultaneously by threads
- the section of code wraped by a mutex can be access by only one thread at a time
- the section starts by unlocking a mutex, and end by locking it
**external function :**
- `memset` : fill memory with a constant byte
- `printf` : format and print data
- `malloc` : allocate dynamic memory
- `free` : free dynamic memory
- `write` : write to a file descriptor
- `usleep` : suspend execution for microseconds intervals
- `gettimeofday`: get time
- `pthread_create` : create a new thread
- `pthread_join` : wait for a thread to finish,
- `pthread_detach` : when a thread is detached it cannot be join, you cannot wait for it to teminate, it will release its ressources on its own when it has finish
- `pthread_mutex_init` : initialize a mutex
- `pthread_mutex_destroy`: destroy a mutex
- `pthread_mutex_unlock` : unlock a mutex
- `pthread_mutex_lock` : lock a mutex

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