doc: samples: philosophers: reformat line length

Overview

********

An implementation of a solution to the Dining Philosophers problem (a classic

multi-thread synchronization problem).  This particular implementation

demonstrates the usage of multiple preemptible and cooperative threads of

differing priorities, as well as dynamic mutexes and thread sleeping.

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.

An implementation of a solution to the Dining Philosophers problem (a classic multi-thread

synchronization problem).  This particular implementation demonstrates the usage of multiple

preemptible and cooperative threads of differing priorities, as well as dynamic mutexes and thread

sleeping.

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.

It is possible to run the demo in coop-only or preempt-only mode. To achieve

this, set these values for CONFIG_NUM_COOP_PRIORITIES and

CONFIG_NUM_PREEMPT_PRIORITIES in prj.conf:

It is possible to run the demo in coop-only or preempt-only mode. To achieve this, set these values

for CONFIG_NUM_COOP_PRIORITIES and CONFIG_NUM_PREEMPT_PRIORITIES in prj.conf:

preempt-only:

  CONFIG_NUM_PREEMPT_PRIORITIES 0

  CONFIG_NUM_COOP_PRIORITIES 6

In these cases, the philosopher threads will run with priorities 0 to 5

(preempt-only) and -7 to -2 (coop-only).

In these cases, the philosopher threads will run with priorities 0 to 5 (preempt-only) and -7 to -2

(coop-only).

Building and Running

********************

This project outputs to the console.  It can be built and executed

on QEMU as follows:

This project outputs to the console.  It can be built and executed on QEMU as follows:

.. zephyr-app-commands::

   :zephyr-app: samples/philosophers

Debug Threads

*************

The philosophers sample by default enables :kconfig:option:`CONFIG_DEBUG_THREAD_INFO`.

This allows tools like OpenOCD and J-link to inspect thread data using

``info threads``.

The philosophers sample by default enables :kconfig:option:`CONFIG_DEBUG_THREAD_INFO`. This allows

tools like OpenOCD and J-link to inspect thread data using ``info threads``.

.. zephyr-app-commands::

   :zephyr-app: samples/philosophers