Re: task_non_contending() for fair_server leads to timer retries

[Juri Lelli]

Hi,

On 15/07/25 16:39, markus.stockhausen@xxxxxx wrote:
> Hi Peter,
> 
> I'm currently investigating issues with the timer-rtl-otto driver in 
> 6.12 longterm on the Realtek MIPS switch platform (Chris is working
> hard to upstream this). While doing so I observed that timer retries 
> continually increase (~6/second) according to /proc/timer_list. The 
> system is otherwise totally idle. 6.6 longterm does not show that issue.
> I'm unsure if this is related but documentation reads like "that's bad". 
> 
> To be sure about this one I nailed it down to the fair server.

Apologies for interjecting before Peter had a chance to reply, but I had
a first look and I wonder if this recent patch from Peter (on
tip/sched/core atm) can already help with the issue, as it should
reduce the number of dl-server dequeues:

cccb45d7c4295 ("sched/deadline: Less agressive dl_server handling")

Can you please check what you see with it?

Thanks!
Juri