sched: Update the cpu_power sum during load-balance

In order to prepare for a more dynamic cpu_power, update the
group sum while walking the sched domains during load-balance.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Acked-by: Gautham R Shenoy <ego@in.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
LKML-Reference: <20090901083825.985050292@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched.c b/kernel/sched.c
index 9d64cec..ecb4a47 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3699,6 +3699,28 @@ static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
 }
 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
 
+static void update_sched_power(struct sched_domain *sd)
+{
+       struct sched_domain *child = sd->child;
+       struct sched_group *group, *sdg = sd->groups;
+       unsigned long power = sdg->__cpu_power;
+
+       if (!child) {
+               /* compute cpu power for this cpu */
+               return;
+       }
+
+       sdg->__cpu_power = 0;
+
+       group = child->groups;
+       do {
+               sdg->__cpu_power += group->__cpu_power;
+               group = group->next;
+       } while (group != child->groups);
+
+       if (power != sdg->__cpu_power)
+               sdg->reciprocal_cpu_power = reciprocal_value(sdg->__cpu_power);
+}
 
 /**
  * update_sg_lb_stats - Update sched_group's statistics for load balancing.
@@ -3712,7 +3734,8 @@ static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
  * @balance: Should we balance.
  * @sgs: variable to hold the statistics for this group.
  */
-static inline void update_sg_lb_stats(struct sched_group *group, int this_cpu,
+static inline void update_sg_lb_stats(struct sched_domain *sd,
+                       struct sched_group *group, int this_cpu,
                        enum cpu_idle_type idle, int load_idx, int *sd_idle,
                        int local_group, const struct cpumask *cpus,
                        int *balance, struct sg_lb_stats *sgs)
@@ -3723,8 +3746,11 @@ static inline void update_sg_lb_stats(struct sched_group *group, int this_cpu,
        unsigned long sum_avg_load_per_task;
        unsigned long avg_load_per_task;
 
-       if (local_group)
+       if (local_group) {
                balance_cpu = group_first_cpu(group);
+               if (balance_cpu == this_cpu)
+                       update_sched_power(sd);
+       }
 
        /* Tally up the load of all CPUs in the group */
        sum_avg_load_per_task = avg_load_per_task = 0;
@@ -3828,7 +3854,7 @@ static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
                local_group = cpumask_test_cpu(this_cpu,
                                               sched_group_cpus(group));
                memset(&sgs, 0, sizeof(sgs));
-               update_sg_lb_stats(group, this_cpu, idle, load_idx, sd_idle,
+               update_sg_lb_stats(sd, group, this_cpu, idle, load_idx, sd_idle,
                                local_group, cpus, balance, &sgs);
 
                if (local_group && balance && !(*balance))
@@ -3863,7 +3889,6 @@ static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
                update_sd_power_savings_stats(group, sds, local_group, &sgs);
                group = group->next;
        } while (group != sd->groups);
-
 }
 
 /**