Re: [PATCH v6 05/16] Documentation/rv: Add documentation about hybrid automata

[Juri Lelli <juri.lelli@redhat.com>]

Hello,

On 25/02/26 10:51, Gabriele Monaco wrote:
> Describe theory and implementation of hybrid automata in the dedicated
> page hybrid_automata.rst
> Include a section on how to integrate a hybrid automaton in
> monitor_synthesis.rst
> Also remove a hanging $ in deterministic_automata.rst
> 
> Reviewed-by: Nam Cao <namcao@linutronix.de>
> Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
> ---

...

> diff --git a/Documentation/trace/rv/hybrid_automata.rst b/Documentation/trace/rv/hybrid_automata.rst
> new file mode 100644
> index 000000000000..39c037a71b89
> --- /dev/null
> +++ b/Documentation/trace/rv/hybrid_automata.rst
> @@ -0,0 +1,341 @@
> +Hybrid Automata
> +===============

...

> +Stall model with invariants (iteration 2)
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +The first iteration isn't exactly what was intended, we can change the model as:
> +
> +- *X* = { ``dequeued``, ``enqueued``, ``running``}
> +- *E* = { ``enqueue``, ``dequeue``, ``switch_in``}
> +- *V* = { ``clk`` }
> +- x\ :subscript:`0` = ``dequeue``
> +- X\ :subscript:`m` = {``dequeue``}
> +- *f* =
> +   - *f*\ (``enqueued``, ``switch_in``) = ``running``
> +   - *f*\ (``running``, ``dequeue``) = ``dequeued``
> +   - *f*\ (``dequeued``, ``enqueue``, ``reset(clk)``) = ``enqueued``
                              ^^^

> +- *i* =
> +   - *i*\ (``enqueued``) = ``clk < threshold``
> +
> +Graphically::
> +
> +    |
> +    |
> +    v
> +  #=========================#
> +  H        dequeued         H <+
> +  #=========================#  |
> +    |                          |
> +    | enqueue; reset(clk)      |
> +    v                          |
> +  +-------------------------+  |
> +  |        enqueued         |  |
> +  |    clk < threshold      |  | dequeue
> +  +-------------------------+  |
> +    |                          |
> +    | switch_in                |
> +    v                          |
> +  +-------------------------+  |
> +  |         running         | -+
> +  +-------------------------+

...

> +  static bool verify_constraint(enum states curr_state, enum events event,
> +                                enum states next_state)
> +  {
> +	bool res = true;
> +
> +	/* Validate guards as part of f */
> +	if (curr_state == enqueued && event == sched_switch_in)
> +		res = get_env(clk) < threshold;
> +	else if (curr_state == dequeued && event == sched_wakeup)
> +		reset_env(clk);

Considering the spec above, does the 'event' need to be 'enqueue'
instead of 'sched_wakeup' (or the other way around)? Or maybe it's
equivalent?

Thanks,
Juri