Re: [RFC 2/3] tick-sched: Keep tick on if hrtimer is due imminently

[Christian Loehle]

On 11/8/24 17:48, Joel Fernandes (Google) wrote:
> In highres mode, the kernel only considers timer wheel events when
> considering whether to keep the tick on (via get_next_interrupt()).
> 
> This seems odd because it consider several other reasons to keep the
> tick on. Further, turning off the tick does not help because once idle
> exit happens due to that imminent hrtimer interrupt, the tick hrtimer
> interrupt is requeued. That means more hrtimer rbtree operations for not
> much benefit.
> 
> Ideally we should not have to do anything because the cpuidle governor
> should not try to the stop the tick because it knows about this
> situation, but apparently it still does try to stop the tick.

Any details on this? Which governor?