Re: [PATCH v2 08/11] sched: get CPU's activity statistic

From: Dietmar Eggemann
Date: Fri May 30 2014 - 05:50:44 EST


On 23/05/14 16:53, Vincent Guittot wrote:
> Monitor the activity level of each group of each sched_domain level. The
> activity is the amount of cpu_power that is currently used on a CPU or group
> of CPUs. We use the runnable_avg_sum and _period to evaluate this activity
> level. In the special use case where the CPU is fully loaded by more than 1
> task, the activity level is set above the cpu_power in order to reflect the
> overload of the CPU
>
> Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>

[...]

> /*
> * select_task_rq_fair: Select target runqueue for the waking task in domains
> * that have the 'sd_flag' flag set. In practice, this is SD_BALANCE_WAKE,
> @@ -5518,6 +5535,7 @@ struct sg_lb_stats {
> unsigned long sum_weighted_load; /* Weighted load of group's tasks */
> unsigned long load_per_task;
> unsigned long group_power;
> + unsigned long group_activity; /* Total activity of the group */
> unsigned int sum_nr_running; /* Nr tasks running in the group */
> unsigned int group_capacity;
> unsigned int idle_cpus;
> @@ -5538,6 +5556,7 @@ struct sd_lb_stats {
> struct sched_group *busiest; /* Busiest group in this sd */
> struct sched_group *local; /* Local group in this sd */
> unsigned long total_load; /* Total load of all groups in sd */
> + unsigned long total_activity; /* Total activity of all groups in sd */
> unsigned long total_pwr; /* Total power of all groups in sd */
> unsigned long avg_load; /* Average load across all groups in sd */
>
> @@ -5557,6 +5576,7 @@ static inline void init_sd_lb_stats(struct sd_lb_stats *sds)
> .busiest = NULL,
> .local = NULL,
> .total_load = 0UL,
> + .total_activity = 0UL,

AFAICS, total_activity is not used right now. Do you intend to use it to
calculate something like avg_activity later (like total_load/avg_load)?

> .total_pwr = 0UL,
> .busiest_stat = {
> .avg_load = 0UL,

[...]

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