Re: [PATCH v2 3/4] sched/fair: Consider SMT in ASYM_PACKING load balance

[Peter Zijlstra]

On Tue, Apr 13, 2021 at 07:04:35PM -0700, Ricardo Neri wrote:
> @@ -8507,6 +8616,18 @@ static bool update_sd_pick_busiest(struct lb_env *env,
>  	if (!sgs->sum_h_nr_running)
>  		return false;
>  
> +	/*
> +	 * @sg may have been tentatively classified as group_asym_packing.
> +	 * Now that we have sufficient information about @sds.local, reassess
> +	 * if asym packing migration can be done. Reclassify @sg. The only
> +	 * possible results are group_has_spare and group_fully_busy.
> +	 */
> +	if (sgs->group_type == group_asym_packing &&
> +	    !asym_can_pull_tasks(env->dst_cpu, sds, sgs, sg)) {
> +		sgs->group_asym_packing = 0;
> +		sgs->group_type = group_classify(env->sd->imbalance_pct, sg, sgs);
> +	}

So if this really is all about not having sds.local in
update_sd_lb_stats(), then that seems fixable. Let me haz a try.