Re: [PATCH v2 0/7] sched: RT throttling cleanup and a bit of documentation

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

Hello,

On 10/11/26 11:56, Paul E. McKenney wrote:
> On Tue, Nov 10, 2026 at 06:34:42PM +0100, Sebastian Andrzej Siewior wrote:
> > People used to disable the RT throttling mechanism by writing -1 to
> > /proc/sys/kernel/sched_rt_runtime_us. Since v6.12 they can still do this
> > but they don't disable RT throttling anymore. Instead this throttling
> > mechanism has been taken over by the fair_server which can be configured
> > via debugfs.
> > This is not really documented by a hint appeared a few cycles later in
> > Documentation/scheduler/sched-rt-group.rst. This can be found once you
> > know what you are looking for because this document describes the RT
> > group scheduling (CONFIG_RT_GROUP_SCHED). The fair_server is used even
> > without it.
> > The then there is global DL resource control which also shares this
> > file proc file (which is stuck if CONFIG_RT_GROUP_SCHED is enabled).
> 
> Nice, thank you!
> 
> Unfortunately but unsurprisingly, this gets the same divide-by-zero
> issue reported (belatedly) on the earlier series:
> 
> https://lore.kernel.org/all/e58e48c3-ac62-40cd-b5d3-2de87db12496@paulmck-laptop/
> 

I wonder if this fixes is

https://lore.kernel.org/lkml/20261108185406.1549770-6-mathieu.desnoyers@efficios.com/

Thanks,
Juri