On Thu, Sep 11, 2014 at 07:26:48PM +0200, Vincent Guittot wrote:

On 11 September 2014 18:15, Peter Zijlstra [off-list ref] wrote:

quoted

On Tue, Aug 26, 2014 at 01:06:54PM +0200, Vincent Guittot wrote:

quoted

+static inline int group_has_free_capacity(struct sg_lb_stats *sgs,
+                     struct lb_env *env)
 {
+     if ((sgs->group_capacity_orig * 100) >
+                     (sgs->group_utilization * env->sd->imbalance_pct))
+             return 1;
+
+     if (sgs->sum_nr_running < sgs->group_weight)
+             return 1;

+     return 0;
+}

+static inline int group_is_overloaded(struct sg_lb_stats *sgs,
+                     struct lb_env *env)
+{
+     if (sgs->sum_nr_running <= sgs->group_weight)
+             return 0;

+     if ((sgs->group_capacity_orig * 100) <
+                     (sgs->group_utilization * env->sd->imbalance_pct))
+             return 1;

+     return 0;
 }

I'm confused about the utilization vs capacity_orig. I see how we should

1st point is that I should compare utilization vs capacity and not
capacity_orig.
I should have replaced capacity_orig by capacity in the functions
above when i move the utilization statistic from
rq->avg.runnable_avg_sum to cfs.usage_load_avg.
rq->avg.runnable_avg_sum was measuring all activity on the cpu whereas
cfs.usage_load_avg integrates only cfs tasks

With this change, we don't need sgs->group_capacity_orig anymore but
only sgs->group_capacity. So sgs->group_capacity_orig can be removed
as it's no more used in the code as sg_capacity_factor has been
removed

Yes, but.. so I suppose we need to add DVFS accounting and remove
cpufreq from the capacity thing. Otherwise I don't see it make sense.