Re: [PATCH v5] cpuidle: menu: Handle stopped tick more aggressively

[Peter Zijlstra]

On Tue, Aug 14, 2018 at 11:44:41PM +0800, leo.yan@xxxxxxxxxx wrote:
> I agree this patch can resolve the issue you mentioned in the commit
> log, but this patch will be fragile for below case, so it will select
> state1 but not state2, how about you think for this case?
> 
> Idle_state0::
> target_residency   TICK_USEC   Prediction
>     |                 |       /
>     V                 V      /
> -----------------------------------------------------> Time length
>                                 ^                 ^
>                                 |                 |
>                             Idle_state1:       Idle_state2:
>                             target_residency   target_residency

If someone can demonstate this is an actual problem; then we need to fix
it I suppose. But it would be very good to have a real world
need/reproducer for it first.