Re: [RFC PATCH] sched/deadline: Avoid dl_server boosting with expired deadline
From: Gabriele Monaco
Date: Fri Oct 31 2025 - 11:52:05 EST
On Fri, 2025-10-31 at 16:44 +0100, Peter Zijlstra wrote:
> On Fri, Oct 31, 2025 at 04:41:22PM +0100, Gabriele Monaco wrote:
>
> > > Humm, let me noodle a bit more on this. Also, I should see if I can get
> > > graphviz to draw ascii art state diagrams :-)
> >
> > Dot doesn't do it but graph-easy does reasonably well.
>
> yep, just found that. Seems to work well:
>
Nice! This can become also a model by the way. But I'd need a few more
tracepoints ;)
>
> +----------------------+
> | A:init | <+
> +----------------------+ |
> | |
> | 1:dl_server_start | 4:pick_task_dl
> v |
> 2:update_curr_dl_se +----------------------+ |
> +---------------------- | | |
> | | B:zero_laxity-wait | |
> +---------------------> | | <+------------------+
> +----------------------+ | |
> | | |
> | 3:dl_server_timer | |
> v | |
> +----------------------+ | |
> +---------------------> | C:running | -+ |
> 2:update_curr_dl_se
> | +----------------------+ |
> | | |
> | 6:dl_server_timer | 5:update_curr_dl_se |
> | v |
> | +----------------------+ |
> +---------------------- | D:replenish | --------------------+
> +----------------------+
>
> Anyway, back to noodling on how to make it stop on idle :-)