diff options
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 45691a2b7861..91bbbe4938ec 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4318,6 +4318,149 @@ static inline bool energy_aware(void) return sched_feat(ENERGY_AWARE); } +/* + * cpu_norm_usage() returns the cpu usage relative to it's current capacity, + * i.e. it's busy ratio, in the range [0..SCHED_LOAD_SCALE] which is useful for + * energy calculations. Using the scale-invariant usage returned by + * get_cpu_usage() and approximating scale-invariant usage by: + * + * usage ~ (curr_freq/max_freq)*1024 * capacity_orig/1024 * running_time/time + * + * the normalized usage can be found using capacity_curr. + * + * capacity_curr = capacity_orig * curr_freq/max_freq + * + * norm_usage = running_time/time ~ usage/capacity_curr + */ +static inline unsigned long cpu_norm_usage(int cpu) +{ + unsigned long capacity_curr = capacity_curr_of(cpu); + + return (get_cpu_usage(cpu) << SCHED_CAPACITY_SHIFT)/capacity_curr; +} + +static unsigned group_max_usage(struct sched_group *sg) +{ + int i; + int max_usage = 0; + + for_each_cpu(i, sched_group_cpus(sg)) + max_usage = max(max_usage, get_cpu_usage(i)); + + return max_usage; +} + +/* + * group_norm_usage() returns the approximated group usage relative to it's + * current capacity (busy ratio) in the range [0..SCHED_LOAD_SCALE] for use in + * energy calculations. Since task executions may or may not overlap in time in + * the group the true normalized usage is between max(cpu_norm_usage(i)) and + * sum(cpu_norm_usage(i)) when iterating over all cpus in the group, i. The + * latter is used as the estimate as it leads to a more pessimistic energy + * estimate (more busy). + */ +static unsigned group_norm_usage(struct sched_group *sg) +{ + int i; + unsigned long usage_sum = 0; + + for_each_cpu(i, sched_group_cpus(sg)) + usage_sum += cpu_norm_usage(i); + + if (usage_sum > SCHED_CAPACITY_SCALE) + return SCHED_CAPACITY_SCALE; + return usage_sum; +} + +static int find_new_capacity(struct sched_group *sg, + struct sched_group_energy *sge) +{ + int idx; + unsigned long util = group_max_usage(sg); + + for (idx = 0; idx < sge->nr_cap_states; idx++) { + if (sge->cap_states[idx].cap >= util) + return idx; + } + + return idx; +} + +/* + * 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; + + if (!sd->child) + cpumask_xor(&visit_cpus, &visit_cpus, sched_group_cpus(sg)); + + if (cpumask_equal(sched_group_cpus(sg), sched_group_cpus(sg_top))) + goto next_cpu; + + } while (sg = sg->next, sg != sd->groups); + } +next_cpu: + continue; + } + + return total_energy; +} + static int wake_wide(struct task_struct *p) { int factor = this_cpu_read(sd_llc_size); |