Subject: [PATCH v5 08/12] sched: move cfs task on a CPU with higher capacity

From: [email-masked] (Peter Zijlstra)
Date: Thu, 11 Sep 2014 12:07:21 +0200

On Tue, Aug 26, 2014 at 01:06:51PM +0200, Vincent Guittot wrote:

> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 18db43e..60ae1ce 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -6049,6 +6049,14 @@ static bool update_sd_pick_busiest(struct lb_env *env,
>  			return true;
>  	}
>  
> +	/*
> +	 * The group capacity is reduced probably because of activity from other
> +	 * sched class or interrupts which use part of the available capacity
> +	 */
> +	if ((sg->sgc->capacity_orig * 100) > (sgs->group_capacity *
> +				env->sd->imbalance_pct))
> +		return true;
> +
>  	return false;
>  }

This is unlikely to have worked as intended. You will never reach this,
except on PowerPC >= 7. All other machines will have bailed at the
!ASYM_PACKING check above this.