Re: [PATCH v4] sched/fair: Replace random newidle_balance with Bresenham accumulator

[Peter Zijlstra]

On Fri, Oct 30, 2026 at 03:16:13PM +0530, K Prateek Nayak wrote:
> Hello Qing,
> 
> On 10/30/2026 2:49 PM, Qing Wang wrote:
> > diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
> > index 919d0fb00bd9..79c477b47510 100644
> > --- a/kernel/sched/topology.c
> > +++ b/kernel/sched/topology.c
> > @@ -2002,6 +2002,7 @@ sd_init(struct sched_domain_topology_level *tl,
> >  		.newidle_call		= 512,
> >  		.newidle_success	= 256,
> >  		.newidle_ratio		= 512,
> > +		.newidle_window_pos	= 0,
> 
> nit.
> 
> I think this value should start in a way that allows newidle balance to run at
> first attempt and then stabilize. Maybe '512; is a good number if not higher?

Funnily enough, treating this as an independent variable and using a
random number works and 'fixes' the slope change problems.