Re: [PATCH v3 1/2] sched: Create architecture specific sched domain distances

[Tim Chen <tim.c.chen@linux.intel.com>]

On Mon, 2025-09-15 at 10:13 -0700, Tim Chen wrote:
> On Mon, 2025-09-15 at 14:37 +0200, Peter Zijlstra wrote:
> > On Thu, Sep 11, 2025 at 11:30:56AM -0700, Tim Chen wrote:

<snip>

> > > +
> > > +	if (sched_record_numa_dist(offline_node, numa_node_dist, &distances,
> > > +				   &nr_node_levels))
> > > +		return;
> > > +
> > > +	WRITE_ONCE(sched_avg_remote_numa_distance,
> > > +		   avg_remote_numa_distance(offline_node));
> > 
> > What is the point of all this? sched_avg_remote_numa_distance isn't
> > actually used anywhere. I'm thinking it doesn't want to be in this patch
> > at the very least.
> 
> sched_avg_remote_numa_distance actually could change when we offline/online a
> node.  I think arch_sched_node_distance(i, j) needs to be changed to
> arch_sched_node_distance(i, j, offline_node) so it knows not to include
> offline_node in its avg distance computation.  I will do that then.
> 

On second thought, GNR and CWF topology only need a remote average
distance.  Whether the offline node is entered into the computation
does not change the resulting sched domain topology.  So paasing
offline node is not necessary and I will update the code as such
and move the average distance computation to x86 specific file.

Tim