59 lines
2.0 KiB
ReStructuredText
59 lines
2.0 KiB
ReStructuredText
.. _cmsis_rtos_v2-sample:
|
|
|
|
Dining Philosophers (CMSI RTOS V2 APIs)
|
|
#######################################
|
|
|
|
Overview
|
|
********
|
|
This sample implements a solution to the `Dining Philosophers problem
|
|
<https://en.wikipedia.org/wiki/Dining_philosophers_problem>`_ (a classic
|
|
multi-thread synchronization problem) using CMSIS RTOS V2 APIs. This particular
|
|
implementation demonstrates the usage of multiple preemptible and cooperative
|
|
threads of differing priorities, as well as mutex/semaphore and thread sleeping
|
|
which uses CMSIS RTOS V2 API implementation in Zephyr.
|
|
|
|
The philosopher always tries to get the lowest fork first (f1 then f2). When
|
|
done, he will give back the forks in the reverse order (f2 then f1). If he
|
|
gets two forks, he is EATING. Otherwise, he is THINKING. Transitional states
|
|
are shown as well, such as STARVING when the philosopher is hungry but the
|
|
forks are not available, and HOLDING ONE FORK when a philosopher is waiting
|
|
for the second fork to be available.
|
|
|
|
Each Philosopher will randomly alternate between the EATING and THINKING state.
|
|
|
|
|
|
Building and Running
|
|
********************
|
|
|
|
This project outputs to the console. It can be built and executed
|
|
on QEMU as follows:
|
|
|
|
.. zephyr-app-commands::
|
|
:zephyr-app: samples/philosophers
|
|
:host-os: unix
|
|
:board: qemu_x86
|
|
:goals: run
|
|
:compact:
|
|
|
|
Sample Output
|
|
=============
|
|
|
|
.. code-block:: console
|
|
|
|
Philosopher 0 [P: 8] HOLDING ONE FORK
|
|
Philosopher 1 [P: 9] HOLDING ONE FORK
|
|
Philosopher 2 [P: 10] EATING [ 575 ms ]
|
|
Philosopher 3 [P: 11] THINKING [ 225 ms ]
|
|
Philosopher 4 [P: 12] THINKING [ 425 ms ]
|
|
Philosopher 5 [P: 13] THINKING [ 325 ms ]
|
|
|
|
Demo Description
|
|
----------------
|
|
An implementation of a solution to the Dining Philosophers
|
|
problem (a classic multi-thread synchronization problem) using
|
|
CMSIS RTOS V2 APIs. This particular implementation demonstrates the
|
|
usage of multiple preemptible threads of differing
|
|
priorities, as well as semaphores and thread sleeping.
|
|
|
|
Exit QEMU by pressing :kbd:`CTRL+A` :kbd:`x`.
|