On 14/09/14 12:41, Peter Zijlstra wrote:
On Thu, Sep 11, 2014 at 07:26:48PM +0200, Vincent Guittot wrote:
On 11 September 2014 18:15, Peter Zijlstra <[email protected]> wrote:
On Tue, Aug 26, 2014 at 01:06:54PM +0200, Vincent Guittot wrote:
+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.
My understanding is that uArch scaling of capacacity_orig (therefore of
capacity too) is done by calling arch_scale_cpu_capacity and frequency
scaling for capacity is done by calling arch_scale_freq_capacity in
update_cpu_capacity. I understand that this patch-set does not provide
an implementation of arch_scale_freq_capacity though.
The uArch and frequency scaling of load & utilization will be added
later. I know that Morten is currently working on a 'uArch and frequency
invariant load & utilization tracking' patch-set.
Although I don't know exactly what you mean by DVFS accounting and
remove cpufreq from the capacity here.
-- Dietmar
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