Re: [RFCv3 PATCH 30/48] sched: Calculate energy consumption of sched_group

From: Sai Gurrappadi
Date: Fri Mar 20 2015 - 14:46:24 EST


On 02/04/2015 10:31 AM, Morten Rasmussen wrote:
> +/*
> + * sched_group_energy(): Returns absolute energy consumption of cpus belonging
> + * to the sched_group including shared resources shared only by members of the
> + * group. Iterates over all cpus in the hierarchy below the sched_group starting
> + * from the bottom working it's way up before going to the next cpu until all
> + * cpus are covered at all levels. The current implementation is likely to
> + * gather the same usage statistics multiple times. This can probably be done in
> + * a faster but more complex way.
> + */
> +static unsigned int sched_group_energy(struct sched_group *sg_top)
> +{
> + struct sched_domain *sd;
> + int cpu, total_energy = 0;
> + struct cpumask visit_cpus;
> + struct sched_group *sg;
> +
> + WARN_ON(!sg_top->sge);
> +
> + cpumask_copy(&visit_cpus, sched_group_cpus(sg_top));
> +
> + while (!cpumask_empty(&visit_cpus)) {
> + struct sched_group *sg_shared_cap = NULL;
> +
> + cpu = cpumask_first(&visit_cpus);
> +
> + /*
> + * Is the group utilization affected by cpus outside this
> + * sched_group?
> + */
> + sd = highest_flag_domain(cpu, SD_SHARE_CAP_STATES);
> + if (sd && sd->parent)
> + sg_shared_cap = sd->parent->groups;
> +
> + for_each_domain(cpu, sd) {
> + sg = sd->groups;
> +
> + /* Has this sched_domain already been visited? */
> + if (sd->child && cpumask_first(sched_group_cpus(sg)) != cpu)
> + break;
> +
> + do {
> + struct sched_group *sg_cap_util;
> + unsigned group_util;
> + int sg_busy_energy, sg_idle_energy;
> + int cap_idx;
> +
> + if (sg_shared_cap && sg_shared_cap->group_weight >= sg->group_weight)
> + sg_cap_util = sg_shared_cap;
> + else
> + sg_cap_util = sg;
> +
> + cap_idx = find_new_capacity(sg_cap_util, sg->sge);
> + group_util = group_norm_usage(sg);
> + sg_busy_energy = (group_util * sg->sge->cap_states[cap_idx].power)
> + >> SCHED_CAPACITY_SHIFT;
> + sg_idle_energy = ((SCHED_LOAD_SCALE-group_util) * sg->sge->idle_states[0].power)
> + >> SCHED_CAPACITY_SHIFT;
> +
> + total_energy += sg_busy_energy + sg_idle_energy;

Should normalize group_util with the newly found capacity instead of
capacity_curr.

-Sai
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