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. 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@linaro.org --- kernel/sched/fair.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index db9b871..7e26f65 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -179,6 +179,11 @@ void sched_init_granularity(void) }
#ifdef CONFIG_SMP +static unsigned long available_of(int cpu) +{ + return cpu_rq(cpu)->cpu_available; +} + #ifdef CONFIG_SCHED_PACKING_TASKS /* * Save the id of the optimal CPU that should be used to pack small tasks @@ -3549,6 +3554,22 @@ done: return target; }
+static int get_cpu_activity(int cpu) +{ + struct rq *rq = cpu_rq(cpu); + u32 sum = rq->avg.runnable_avg_sum; + u32 period = rq->avg.runnable_avg_period; + + sum = min(sum, period); + + if (sum == period) { + u32 overload = rq->nr_running > 1 ? 1 : 0; + return available_of(cpu) + overload; + } + + return (sum * available_of(cpu)) / period; +} + /* * sched_balance_self: balance the current task (running on cpu) in domains * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and @@ -4430,6 +4451,7 @@ 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; @@ -4446,6 +4468,7 @@ 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 */
@@ -4465,6 +4488,7 @@ static inline void init_sd_lb_stats(struct sd_lb_stats *sds) .busiest = NULL, .local = NULL, .total_load = 0UL, + .total_activity = 0UL, .total_pwr = 0UL, .busiest_stat = { .avg_load = 0UL, @@ -4771,6 +4795,7 @@ static inline void update_sg_lb_stats(struct lb_env *env, }
sgs->group_load += load; + sgs->group_activity += get_cpu_activity(i); sgs->sum_nr_running += nr_running; sgs->sum_weighted_load += weighted_cpuload(i); if (idle_cpu(i)) @@ -4894,6 +4919,7 @@ static inline void update_sd_lb_stats(struct lb_env *env,
/* Now, start updating sd_lb_stats */ sds->total_load += sgs->group_load; + sds->total_activity += sgs->group_activity; sds->total_pwr += sgs->group_power;
if (!local_group && update_sd_pick_busiest(env, sds, sg, sgs)) {