Merge branch 'linux-linaro-lsk-v4.4' into linux-linaro-lsk-v4.4-android
[firefly-linux-kernel-4.4.55.git] / kernel / sched / tune.c
index 540b945a01ce4c8cb834c7a14ddafa35bccaefa0..505d7b35b0e1fd27fb29cb7aa6b039c6ddc7e886 100644 (file)
 #include <linux/cgroup.h>
 #include <linux/err.h>
+#include <linux/kernel.h>
 #include <linux/percpu.h>
 #include <linux/printk.h>
 #include <linux/rcupdate.h>
 #include <linux/slab.h>
 
+#include <trace/events/sched.h>
+
 #include "sched.h"
+#include "tune.h"
+
+#ifdef CONFIG_CGROUP_SCHEDTUNE
+static bool schedtune_initialized = false;
+#endif
 
 unsigned int sysctl_sched_cfs_boost __read_mostly;
 
+extern struct target_nrg schedtune_target_nrg;
+
+/* Performance Boost region (B) threshold params */
+static int perf_boost_idx;
+
+/* Performance Constraint region (C) threshold params */
+static int perf_constrain_idx;
+
+/**
+ * Performance-Energy (P-E) Space thresholds constants
+ */
+struct threshold_params {
+       int nrg_gain;
+       int cap_gain;
+};
+
+/*
+ * System specific P-E space thresholds constants
+ */
+static struct threshold_params
+threshold_gains[] = {
+       { 0, 5 }, /*   < 10% */
+       { 1, 5 }, /*   < 20% */
+       { 2, 5 }, /*   < 30% */
+       { 3, 5 }, /*   < 40% */
+       { 4, 5 }, /*   < 50% */
+       { 5, 4 }, /*   < 60% */
+       { 5, 3 }, /*   < 70% */
+       { 5, 2 }, /*   < 80% */
+       { 5, 1 }, /*   < 90% */
+       { 5, 0 }  /* <= 100% */
+};
+
+static int
+__schedtune_accept_deltas(int nrg_delta, int cap_delta,
+                         int perf_boost_idx, int perf_constrain_idx)
+{
+       int payoff = -INT_MAX;
+       int gain_idx = -1;
+
+       /* Performance Boost (B) region */
+       if (nrg_delta >= 0 && cap_delta > 0)
+               gain_idx = perf_boost_idx;
+       /* Performance Constraint (C) region */
+       else if (nrg_delta < 0 && cap_delta <= 0)
+               gain_idx = perf_constrain_idx;
+
+       /* Default: reject schedule candidate */
+       if (gain_idx == -1)
+               return payoff;
+
+       /*
+        * Evaluate "Performance Boost" vs "Energy Increase"
+        *
+        * - Performance Boost (B) region
+        *
+        *   Condition: nrg_delta > 0 && cap_delta > 0
+        *   Payoff criteria:
+        *     cap_gain / nrg_gain  < cap_delta / nrg_delta =
+        *     cap_gain * nrg_delta < cap_delta * nrg_gain
+        *   Note that since both nrg_gain and nrg_delta are positive, the
+        *   inequality does not change. Thus:
+        *
+        *     payoff = (cap_delta * nrg_gain) - (cap_gain * nrg_delta)
+        *
+        * - Performance Constraint (C) region
+        *
+        *   Condition: nrg_delta < 0 && cap_delta < 0
+        *   payoff criteria:
+        *     cap_gain / nrg_gain  > cap_delta / nrg_delta =
+        *     cap_gain * nrg_delta < cap_delta * nrg_gain
+        *   Note that since nrg_gain > 0 while nrg_delta < 0, the
+        *   inequality change. Thus:
+        *
+        *     payoff = (cap_delta * nrg_gain) - (cap_gain * nrg_delta)
+        *
+        * This means that, in case of same positive defined {cap,nrg}_gain
+        * for both the B and C regions, we can use the same payoff formula
+        * where a positive value represents the accept condition.
+        */
+       payoff  = cap_delta * threshold_gains[gain_idx].nrg_gain;
+       payoff -= nrg_delta * threshold_gains[gain_idx].cap_gain;
+
+       return payoff;
+}
+
 #ifdef CONFIG_CGROUP_SCHEDTUNE
 
 /*
@@ -26,6 +120,15 @@ struct schedtune {
        /* Boost value for tasks on that SchedTune CGroup */
        int boost;
 
+       /* Performance Boost (B) region threshold params */
+       int perf_boost_idx;
+
+       /* Performance Constraint (C) region threshold params */
+       int perf_constrain_idx;
+
+       /* Hint to bias scheduling of tasks on that SchedTune CGroup
+        * towards idle CPUs */
+       int prefer_idle;
 };
 
 static inline struct schedtune *css_st(struct cgroup_subsys_state *css)
@@ -55,8 +158,42 @@ static inline struct schedtune *parent_st(struct schedtune *st)
 static struct schedtune
 root_schedtune = {
        .boost  = 0,
+       .perf_boost_idx = 0,
+       .perf_constrain_idx = 0,
+       .prefer_idle = 0,
 };
 
+int
+schedtune_accept_deltas(int nrg_delta, int cap_delta,
+                       struct task_struct *task)
+{
+       struct schedtune *ct;
+       int perf_boost_idx;
+       int perf_constrain_idx;
+
+       /* Optimal (O) region */
+       if (nrg_delta < 0 && cap_delta > 0) {
+               trace_sched_tune_filter(nrg_delta, cap_delta, 0, 0, 1, 0);
+               return INT_MAX;
+       }
+
+       /* Suboptimal (S) region */
+       if (nrg_delta > 0 && cap_delta < 0) {
+               trace_sched_tune_filter(nrg_delta, cap_delta, 0, 0, -1, 5);
+               return -INT_MAX;
+       }
+
+       /* Get task specific perf Boost/Constraints indexes */
+       rcu_read_lock();
+       ct = task_schedtune(task);
+       perf_boost_idx = ct->perf_boost_idx;
+       perf_constrain_idx = ct->perf_constrain_idx;
+       rcu_read_unlock();
+
+       return __schedtune_accept_deltas(nrg_delta, cap_delta,
+                       perf_boost_idx, perf_constrain_idx);
+}
+
 /*
  * Maximum number of boost groups to support
  * When per-task boosting is used we still allow only limited number of
@@ -86,13 +223,16 @@ static struct schedtune *allocated_group[BOOSTGROUPS_COUNT] = {
  */
 struct boost_groups {
        /* Maximum boost value for all RUNNABLE tasks on a CPU */
-       unsigned boost_max;
+       bool idle;
+       int boost_max;
        struct {
                /* The boost for tasks on that boost group */
-               unsigned boost;
+               int boost;
                /* Count of RUNNABLE tasks on that boost group */
                unsigned tasks;
        } group[BOOSTGROUPS_COUNT];
+       /* CPU's boost group locking */
+       raw_spinlock_t lock;
 };
 
 /* Boost groups affecting each CPU in the system */
@@ -102,7 +242,7 @@ static void
 schedtune_cpu_update(int cpu)
 {
        struct boost_groups *bg;
-       unsigned boost_max;
+       int boost_max;
        int idx;
 
        bg = &per_cpu(cpu_boost_groups, cpu);
@@ -116,9 +256,13 @@ schedtune_cpu_update(int cpu)
                 */
                if (bg->group[idx].tasks == 0)
                        continue;
+
                boost_max = max(boost_max, bg->group[idx].boost);
        }
-
+       /* Ensures boost_max is non-negative when all cgroup boost values
+        * are neagtive. Avoids under-accounting of cpu capacity which may cause
+        * task stacking and frequency spikes.*/
+       boost_max = max(boost_max, 0);
        bg->boost_max = boost_max;
 }
 
@@ -148,33 +292,39 @@ schedtune_boostgroup_update(int idx, int boost)
                /* Check if this update increase current max */
                if (boost > cur_boost_max && bg->group[idx].tasks) {
                        bg->boost_max = boost;
+                       trace_sched_tune_boostgroup_update(cpu, 1, bg->boost_max);
                        continue;
                }
 
                /* Check if this update has decreased current max */
-               if (cur_boost_max == old_boost && old_boost > boost)
+               if (cur_boost_max == old_boost && old_boost > boost) {
                        schedtune_cpu_update(cpu);
+                       trace_sched_tune_boostgroup_update(cpu, -1, bg->boost_max);
+                       continue;
+               }
+
+               trace_sched_tune_boostgroup_update(cpu, 0, bg->boost_max);
        }
 
        return 0;
 }
 
+#define ENQUEUE_TASK  1
+#define DEQUEUE_TASK -1
+
 static inline void
 schedtune_tasks_update(struct task_struct *p, int cpu, int idx, int task_count)
 {
-       struct boost_groups *bg;
-       int tasks;
-
-       bg = &per_cpu(cpu_boost_groups, cpu);
+       struct boost_groups *bg = &per_cpu(cpu_boost_groups, cpu);
+       int tasks = bg->group[idx].tasks + task_count;
 
        /* Update boosted tasks count while avoiding to make it negative */
-       if (task_count < 0 && bg->group[idx].tasks <= -task_count)
-               bg->group[idx].tasks = 0;
-       else
-               bg->group[idx].tasks += task_count;
+       bg->group[idx].tasks = max(0, tasks);
+
+       trace_sched_tune_tasks_update(p, cpu, tasks, idx,
+                       bg->group[idx].boost, bg->boost_max);
 
        /* Boost group activation or deactivation on that RQ */
-       tasks = bg->group[idx].tasks;
        if (tasks == 1 || tasks == 0)
                schedtune_cpu_update(cpu);
 }
@@ -184,9 +334,14 @@ schedtune_tasks_update(struct task_struct *p, int cpu, int idx, int task_count)
  */
 void schedtune_enqueue_task(struct task_struct *p, int cpu)
 {
+       struct boost_groups *bg = &per_cpu(cpu_boost_groups, cpu);
+       unsigned long irq_flags;
        struct schedtune *st;
        int idx;
 
+       if (!unlikely(schedtune_initialized))
+               return;
+
        /*
         * When a task is marked PF_EXITING by do_exit() it's going to be
         * dequeued and enqueued multiple times in the exit path.
@@ -196,13 +351,109 @@ void schedtune_enqueue_task(struct task_struct *p, int cpu)
        if (p->flags & PF_EXITING)
                return;
 
-       /* Get task boost group */
+       /*
+        * Boost group accouting is protected by a per-cpu lock and requires
+        * interrupt to be disabled to avoid race conditions for example on
+        * do_exit()::cgroup_exit() and task migration.
+        */
+       raw_spin_lock_irqsave(&bg->lock, irq_flags);
        rcu_read_lock();
+
        st = task_schedtune(p);
        idx = st->idx;
+
+       schedtune_tasks_update(p, cpu, idx, ENQUEUE_TASK);
+
        rcu_read_unlock();
+       raw_spin_unlock_irqrestore(&bg->lock, irq_flags);
+}
 
-       schedtune_tasks_update(p, cpu, idx, 1);
+int schedtune_allow_attach(struct cgroup_taskset *tset)
+{
+       /* We always allows tasks to be moved between existing CGroups */
+       return 0;
+}
+
+int schedtune_can_attach(struct cgroup_taskset *tset)
+{
+       struct task_struct *task;
+       struct cgroup_subsys_state *css;
+       struct boost_groups *bg;
+       unsigned long irq_flags;
+       unsigned int cpu;
+       struct rq *rq;
+       int src_bg; /* Source boost group index */
+       int dst_bg; /* Destination boost group index */
+       int tasks;
+
+       if (!unlikely(schedtune_initialized))
+               return 0;
+
+
+       cgroup_taskset_for_each(task, css, tset) {
+
+               /*
+                * Lock the CPU's RQ the task is enqueued to avoid race
+                * conditions with migration code while the task is being
+                * accounted
+                */
+               rq = lock_rq_of(task, &irq_flags);
+
+               if (!task->on_rq) {
+                       unlock_rq_of(rq, task, &irq_flags);
+                       continue;
+               }
+
+               /*
+                * Boost group accouting is protected by a per-cpu lock and requires
+                * interrupt to be disabled to avoid race conditions on...
+                */
+               cpu = cpu_of(rq);
+               bg = &per_cpu(cpu_boost_groups, cpu);
+               raw_spin_lock(&bg->lock);
+
+               dst_bg = css_st(css)->idx;
+               src_bg = task_schedtune(task)->idx;
+
+               /*
+                * Current task is not changing boostgroup, which can
+                * happen when the new hierarchy is in use.
+                */
+               if (unlikely(dst_bg == src_bg)) {
+                       raw_spin_unlock(&bg->lock);
+                       unlock_rq_of(rq, task, &irq_flags);
+                       continue;
+               }
+
+               /*
+                * This is the case of a RUNNABLE task which is switching its
+                * current boost group.
+                */
+
+               /* Move task from src to dst boost group */
+               tasks = bg->group[src_bg].tasks - 1;
+               bg->group[src_bg].tasks = max(0, tasks);
+               bg->group[dst_bg].tasks += 1;
+
+               raw_spin_unlock(&bg->lock);
+               unlock_rq_of(rq, task, &irq_flags);
+
+               /* Update CPU boost group */
+               if (bg->group[src_bg].tasks == 0 || bg->group[dst_bg].tasks == 1)
+                       schedtune_cpu_update(task_cpu(task));
+
+       }
+
+       return 0;
+}
+
+void schedtune_cancel_attach(struct cgroup_taskset *tset)
+{
+       /* This can happen only if SchedTune controller is mounted with
+        * other hierarchies ane one of them fails. Since usually SchedTune is
+        * mouted on its own hierarcy, for the time being we do not implement
+        * a proper rollback mechanism */
+       WARN(1, "SchedTune cancel attach not implemented");
 }
 
 /*
@@ -210,26 +461,62 @@ void schedtune_enqueue_task(struct task_struct *p, int cpu)
  */
 void schedtune_dequeue_task(struct task_struct *p, int cpu)
 {
+       struct boost_groups *bg = &per_cpu(cpu_boost_groups, cpu);
+       unsigned long irq_flags;
        struct schedtune *st;
        int idx;
 
+       if (!unlikely(schedtune_initialized))
+               return;
+
        /*
         * When a task is marked PF_EXITING by do_exit() it's going to be
         * dequeued and enqueued multiple times in the exit path.
         * Thus we avoid any further update, since we do not want to change
         * CPU boosting while the task is exiting.
-        * The last dequeue will be done by cgroup exit() callback.
+        * The last dequeue is already enforce by the do_exit() code path
+        * via schedtune_exit_task().
         */
        if (p->flags & PF_EXITING)
                return;
 
-       /* Get task boost group */
+       /*
+        * Boost group accouting is protected by a per-cpu lock and requires
+        * interrupt to be disabled to avoid race conditions on...
+        */
+       raw_spin_lock_irqsave(&bg->lock, irq_flags);
        rcu_read_lock();
+
        st = task_schedtune(p);
        idx = st->idx;
+
+       schedtune_tasks_update(p, cpu, idx, DEQUEUE_TASK);
+
        rcu_read_unlock();
+       raw_spin_unlock_irqrestore(&bg->lock, irq_flags);
+}
+
+void schedtune_exit_task(struct task_struct *tsk)
+{
+       struct schedtune *st;
+       unsigned long irq_flags;
+       unsigned int cpu;
+       struct rq *rq;
+       int idx;
+
+       if (!unlikely(schedtune_initialized))
+               return;
+
+       rq = lock_rq_of(tsk, &irq_flags);
+       rcu_read_lock();
 
-       schedtune_tasks_update(p, cpu, idx, -1);
+       cpu = cpu_of(rq);
+       st = task_schedtune(tsk);
+       idx = st->idx;
+       schedtune_tasks_update(tsk, cpu, idx, DEQUEUE_TASK);
+
+       rcu_read_unlock();
+       unlock_rq_of(rq, tsk, &irq_flags);
 }
 
 int schedtune_cpu_boost(int cpu)
@@ -240,7 +527,53 @@ int schedtune_cpu_boost(int cpu)
        return bg->boost_max;
 }
 
+int schedtune_task_boost(struct task_struct *p)
+{
+       struct schedtune *st;
+       int task_boost;
+
+       /* Get task boost value */
+       rcu_read_lock();
+       st = task_schedtune(p);
+       task_boost = st->boost;
+       rcu_read_unlock();
+
+       return task_boost;
+}
+
+int schedtune_prefer_idle(struct task_struct *p)
+{
+       struct schedtune *st;
+       int prefer_idle;
+
+       /* Get prefer_idle value */
+       rcu_read_lock();
+       st = task_schedtune(p);
+       prefer_idle = st->prefer_idle;
+       rcu_read_unlock();
+
+       return prefer_idle;
+}
+
 static u64
+prefer_idle_read(struct cgroup_subsys_state *css, struct cftype *cft)
+{
+       struct schedtune *st = css_st(css);
+
+       return st->prefer_idle;
+}
+
+static int
+prefer_idle_write(struct cgroup_subsys_state *css, struct cftype *cft,
+           u64 prefer_idle)
+{
+       struct schedtune *st = css_st(css);
+       st->prefer_idle = prefer_idle;
+
+       return 0;
+}
+
+static s64
 boost_read(struct cgroup_subsys_state *css, struct cftype *cft)
 {
        struct schedtune *st = css_st(css);
@@ -250,28 +583,51 @@ boost_read(struct cgroup_subsys_state *css, struct cftype *cft)
 
 static int
 boost_write(struct cgroup_subsys_state *css, struct cftype *cft,
-           u64 boost)
+           s64 boost)
 {
        struct schedtune *st = css_st(css);
+       unsigned threshold_idx;
+       int boost_pct;
 
-       if (boost < 0 || boost > 100)
+       if (boost < -100 || boost > 100)
                return -EINVAL;
+       boost_pct = boost;
+
+       /*
+        * Update threshold params for Performance Boost (B)
+        * and Performance Constraint (C) regions.
+        * The current implementatio uses the same cuts for both
+        * B and C regions.
+        */
+       threshold_idx = clamp(boost_pct, 0, 99) / 10;
+       st->perf_boost_idx = threshold_idx;
+       st->perf_constrain_idx = threshold_idx;
 
        st->boost = boost;
-       if (css == &root_schedtune.css)
+       if (css == &root_schedtune.css) {
                sysctl_sched_cfs_boost = boost;
+               perf_boost_idx  = threshold_idx;
+               perf_constrain_idx  = threshold_idx;
+       }
 
        /* Update CPU boost */
        schedtune_boostgroup_update(st->idx, st->boost);
 
+       trace_sched_tune_config(st->boost);
+
        return 0;
 }
 
 static struct cftype files[] = {
        {
                .name = "boost",
-               .read_u64 = boost_read,
-               .write_u64 = boost_write,
+               .read_s64 = boost_read,
+               .write_s64 = boost_write,
+       },
+       {
+               .name = "prefer_idle",
+               .read_u64 = prefer_idle_read,
+               .write_u64 = prefer_idle_write,
        },
        { }     /* terminate */
 };
@@ -295,33 +651,14 @@ schedtune_boostgroup_init(struct schedtune *st)
        return 0;
 }
 
-static int
-schedtune_init(void)
-{
-       struct boost_groups *bg;
-       int cpu;
-
-       /* Initialize the per CPU boost groups */
-       for_each_possible_cpu(cpu) {
-               bg = &per_cpu(cpu_boost_groups, cpu);
-               memset(bg, 0, sizeof(struct boost_groups));
-       }
-
-       pr_info("  schedtune configured to support %d boost groups\n",
-               BOOSTGROUPS_COUNT);
-       return 0;
-}
-
 static struct cgroup_subsys_state *
 schedtune_css_alloc(struct cgroup_subsys_state *parent_css)
 {
        struct schedtune *st;
        int idx;
 
-       if (!parent_css) {
-               schedtune_init();
+       if (!parent_css)
                return &root_schedtune.css;
-       }
 
        /* Allow only single level hierachies */
        if (parent_css != &root_schedtune.css) {
@@ -378,10 +715,53 @@ schedtune_css_free(struct cgroup_subsys_state *css)
 struct cgroup_subsys schedtune_cgrp_subsys = {
        .css_alloc      = schedtune_css_alloc,
        .css_free       = schedtune_css_free,
+       .allow_attach   = schedtune_allow_attach,
+       .can_attach     = schedtune_can_attach,
+       .cancel_attach  = schedtune_cancel_attach,
        .legacy_cftypes = files,
        .early_init     = 1,
 };
 
+static inline void
+schedtune_init_cgroups(void)
+{
+       struct boost_groups *bg;
+       int cpu;
+
+       /* Initialize the per CPU boost groups */
+       for_each_possible_cpu(cpu) {
+               bg = &per_cpu(cpu_boost_groups, cpu);
+               memset(bg, 0, sizeof(struct boost_groups));
+       }
+
+       pr_info("schedtune: configured to support %d boost groups\n",
+               BOOSTGROUPS_COUNT);
+
+       schedtune_initialized = true;
+}
+
+#else /* CONFIG_CGROUP_SCHEDTUNE */
+
+int
+schedtune_accept_deltas(int nrg_delta, int cap_delta,
+                       struct task_struct *task)
+{
+       /* Optimal (O) region */
+       if (nrg_delta < 0 && cap_delta > 0) {
+               trace_sched_tune_filter(nrg_delta, cap_delta, 0, 0, 1, 0);
+               return INT_MAX;
+       }
+
+       /* Suboptimal (S) region */
+       if (nrg_delta > 0 && cap_delta < 0) {
+               trace_sched_tune_filter(nrg_delta, cap_delta, 0, 0, -1, 5);
+               return -INT_MAX;
+       }
+
+       return __schedtune_accept_deltas(nrg_delta, cap_delta,
+                       perf_boost_idx, perf_constrain_idx);
+}
+
 #endif /* CONFIG_CGROUP_SCHEDTUNE */
 
 int
@@ -390,9 +770,182 @@ sysctl_sched_cfs_boost_handler(struct ctl_table *table, int write,
                               loff_t *ppos)
 {
        int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+       unsigned threshold_idx;
+       int boost_pct;
 
        if (ret || !write)
                return ret;
 
+       if (sysctl_sched_cfs_boost < -100 || sysctl_sched_cfs_boost > 100)
+               return -EINVAL;
+       boost_pct = sysctl_sched_cfs_boost;
+
+       /*
+        * Update threshold params for Performance Boost (B)
+        * and Performance Constraint (C) regions.
+        * The current implementatio uses the same cuts for both
+        * B and C regions.
+        */
+       threshold_idx = clamp(boost_pct, 0, 99) / 10;
+       perf_boost_idx = threshold_idx;
+       perf_constrain_idx = threshold_idx;
+
+       return 0;
+}
+
+#ifdef CONFIG_SCHED_DEBUG
+static void
+schedtune_test_nrg(unsigned long delta_pwr)
+{
+       unsigned long test_delta_pwr;
+       unsigned long test_norm_pwr;
+       int idx;
+
+       /*
+        * Check normalization constants using some constant system
+        * energy values
+        */
+       pr_info("schedtune: verify normalization constants...\n");
+       for (idx = 0; idx < 6; ++idx) {
+               test_delta_pwr = delta_pwr >> idx;
+
+               /* Normalize on max energy for target platform */
+               test_norm_pwr = reciprocal_divide(
+                                       test_delta_pwr << SCHED_LOAD_SHIFT,
+                                       schedtune_target_nrg.rdiv);
+
+               pr_info("schedtune: max_pwr/2^%d: %4lu => norm_pwr: %5lu\n",
+                       idx, test_delta_pwr, test_norm_pwr);
+       }
+}
+#else
+#define schedtune_test_nrg(delta_pwr)
+#endif
+
+/*
+ * Compute the min/max power consumption of a cluster and all its CPUs
+ */
+static void
+schedtune_add_cluster_nrg(
+               struct sched_domain *sd,
+               struct sched_group *sg,
+               struct target_nrg *ste)
+{
+       struct sched_domain *sd2;
+       struct sched_group *sg2;
+
+       struct cpumask *cluster_cpus;
+       char str[32];
+
+       unsigned long min_pwr;
+       unsigned long max_pwr;
+       int cpu;
+
+       /* Get Cluster energy using EM data for the first CPU */
+       cluster_cpus = sched_group_cpus(sg);
+       snprintf(str, 32, "CLUSTER[%*pbl]",
+                cpumask_pr_args(cluster_cpus));
+
+       min_pwr = sg->sge->idle_states[sg->sge->nr_idle_states - 1].power;
+       max_pwr = sg->sge->cap_states[sg->sge->nr_cap_states - 1].power;
+       pr_info("schedtune: %-17s min_pwr: %5lu max_pwr: %5lu\n",
+               str, min_pwr, max_pwr);
+
+       /*
+        * Keep track of this cluster's energy in the computation of the
+        * overall system energy
+        */
+       ste->min_power += min_pwr;
+       ste->max_power += max_pwr;
+
+       /* Get CPU energy using EM data for each CPU in the group */
+       for_each_cpu(cpu, cluster_cpus) {
+               /* Get a SD view for the specific CPU */
+               for_each_domain(cpu, sd2) {
+                       /* Get the CPU group */
+                       sg2 = sd2->groups;
+                       min_pwr = sg2->sge->idle_states[sg2->sge->nr_idle_states - 1].power;
+                       max_pwr = sg2->sge->cap_states[sg2->sge->nr_cap_states - 1].power;
+
+                       ste->min_power += min_pwr;
+                       ste->max_power += max_pwr;
+
+                       snprintf(str, 32, "CPU[%d]", cpu);
+                       pr_info("schedtune: %-17s min_pwr: %5lu max_pwr: %5lu\n",
+                               str, min_pwr, max_pwr);
+
+                       /*
+                        * Assume we have EM data only at the CPU and
+                        * the upper CLUSTER level
+                        */
+                       BUG_ON(!cpumask_equal(
+                               sched_group_cpus(sg),
+                               sched_group_cpus(sd2->parent->groups)
+                               ));
+                       break;
+               }
+       }
+}
+
+/*
+ * Initialize the constants required to compute normalized energy.
+ * The values of these constants depends on the EM data for the specific
+ * target system and topology.
+ * Thus, this function is expected to be called by the code
+ * that bind the EM to the topology information.
+ */
+static int
+schedtune_init(void)
+{
+       struct target_nrg *ste = &schedtune_target_nrg;
+       unsigned long delta_pwr = 0;
+       struct sched_domain *sd;
+       struct sched_group *sg;
+
+       pr_info("schedtune: init normalization constants...\n");
+       ste->max_power = 0;
+       ste->min_power = 0;
+
+       rcu_read_lock();
+
+       /*
+        * When EAS is in use, we always have a pointer to the highest SD
+        * which provides EM data.
+        */
+       sd = rcu_dereference(per_cpu(sd_ea, cpumask_first(cpu_online_mask)));
+       if (!sd) {
+               pr_info("schedtune: no energy model data\n");
+               goto nodata;
+       }
+
+       sg = sd->groups;
+       do {
+               schedtune_add_cluster_nrg(sd, sg, ste);
+       } while (sg = sg->next, sg != sd->groups);
+
+       rcu_read_unlock();
+
+       pr_info("schedtune: %-17s min_pwr: %5lu max_pwr: %5lu\n",
+               "SYSTEM", ste->min_power, ste->max_power);
+
+       /* Compute normalization constants */
+       delta_pwr = ste->max_power - ste->min_power;
+       ste->rdiv = reciprocal_value(delta_pwr);
+       pr_info("schedtune: using normalization constants mul: %u sh1: %u sh2: %u\n",
+               ste->rdiv.m, ste->rdiv.sh1, ste->rdiv.sh2);
+
+       schedtune_test_nrg(delta_pwr);
+
+#ifdef CONFIG_CGROUP_SCHEDTUNE
+       schedtune_init_cgroups();
+#else
+       pr_info("schedtune: configured to support global boosting only\n");
+#endif
+
        return 0;
+
+nodata:
+       rcu_read_unlock();
+       return -EINVAL;
 }
+postcore_initcall(schedtune_init);