blob: 78b99bb840108f36d9b0bbfe3841ee11d03b5468 [file] [log] [blame]
#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
bool schedtune_initialized = false;
#endif
unsigned int sysctl_sched_cfs_boost __read_mostly;
extern struct reciprocal_value schedtune_spc_rdiv;
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
/*
* EAS scheduler tunables for task groups.
*
* When CGroup support is enabled, we have to synchronize two different
* paths:
* - slow path: where CGroups are created/updated/removed
* - fast path: where tasks in a CGroups are accounted
*
* The slow path tracks (a limited number of) CGroups and maps each on a
* "boost_group" index. The fastpath accounts tasks currently RUNNABLE on each
* "boost_group".
*
* Once a new CGroup is created, a boost group idx is assigned and the
* corresponding "boost_group" marked as valid on each CPU.
* Once a CGroup is release, the corresponding "boost_group" is marked as
* invalid on each CPU. The CPU boost value (boost_max) is aggregated by
* considering only valid boost_groups with a non null tasks counter.
*
* .:: Locking strategy
*
* The fast path uses a spin lock for each CPU boost_group which protects the
* tasks counter.
*
* The "valid" and "boost" values of each CPU boost_group is instead
* protected by the RCU lock provided by the CGroups callbacks. Thus, only the
* slow path can access and modify the boost_group attribtues of each CPU.
* The fast path will catch up the most updated values at the next scheduling
* event (i.e. enqueue/dequeue).
*
* |
* SLOW PATH | FAST PATH
* CGroup add/update/remove | Scheduler enqueue/dequeue events
* |
* |
* | DEFINE_PER_CPU(struct boost_groups)
* | +--------------+----+---+----+----+
* | | idle | | | | |
* | | boost_max | | | | |
* | +---->lock | | | | |
* struct schedtune allocated_groups | | | group[ ] | | | | |
* +------------------------------+ +-------+ | | +--+---------+-+----+---+----+----+
* | idx | | | | | | valid |
* | boots / prefer_idle | | | | | | boost |
* | perf_{boost/constraints}_idx | <---------+(*) | | | | tasks | <------------+
* | css | +-------+ | | +---------+ |
* +-+----------------------------+ | | | | | | |
* ^ | | | | | | |
* | +-------+ | | +---------+ |
* | | | | | | | |
* | | | | | | | |
* | +-------+ | | +---------+ |
* | zmalloc | | | | | | |
* | | | | | | | |
* | +-------+ | | +---------+ |
* + BOOSTGROUPS_COUNT | | BOOSTGROUPS_COUNT |
* schedtune_boostgroup_init() | + |
* | schedtune_{en,de}queue_task() |
* | +
* | schedtune_tasks_update()
* |
*/
/* SchdTune tunables for a group of tasks */
struct schedtune {
/* SchedTune CGroup subsystem */
struct cgroup_subsys_state css;
/* Boost group allocated ID */
int idx;
/* 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)
{
return css ? container_of(css, struct schedtune, css) : NULL;
}
static inline struct schedtune *task_schedtune(struct task_struct *tsk)
{
return css_st(task_css(tsk, schedtune_cgrp_id));
}
static inline struct schedtune *parent_st(struct schedtune *st)
{
return css_st(st->css.parent);
}
/*
* SchedTune root control group
* The root control group is used to defined a system-wide boosting tuning,
* which is applied to all tasks in the system.
* Task specific boost tuning could be specified by creating and
* configuring a child control group under the root one.
* By default, system-wide boosting is disabled, i.e. no boosting is applied
* to tasks which are not into a child control group.
*/
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
* boost groups for two main reasons:
* 1. on a real system we usually have only few classes of workloads which
* make sense to boost with different values (e.g. background vs foreground
* tasks, interactive vs low-priority tasks)
* 2. a limited number allows for a simpler and more memory/time efficient
* implementation especially for the computation of the per-CPU boost
* value
*/
#define BOOSTGROUPS_COUNT 5
/* Array of configured boostgroups */
static struct schedtune *allocated_group[BOOSTGROUPS_COUNT] = {
&root_schedtune,
NULL,
};
/* SchedTune boost groups
* Keep track of all the boost groups which impact on CPU, for example when a
* CPU has two RUNNABLE tasks belonging to two different boost groups and thus
* likely with different boost values.
* Since on each system we expect only a limited number of boost groups, here
* we use a simple array to keep track of the metrics required to compute the
* maximum per-CPU boosting value.
*/
struct boost_groups {
/* Maximum boost value for all RUNNABLE tasks on a CPU */
int boost_max;
struct {
/* True when this boost group maps an actual cgroup */
bool valid;
/* The boost for tasks on that boost group */
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 */
DEFINE_PER_CPU(struct boost_groups, cpu_boost_groups);
static void
schedtune_cpu_update(int cpu)
{
struct boost_groups *bg;
int boost_max;
int idx;
bg = &per_cpu(cpu_boost_groups, cpu);
/* The root boost group is always active */
boost_max = bg->group[0].boost;
for (idx = 1; idx < BOOSTGROUPS_COUNT; ++idx) {
/* Ignore non boostgroups not mapping a cgroup */
if (!bg->group[idx].valid)
continue;
/*
* A boost group affects a CPU only if it has
* RUNNABLE tasks on that 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;
}
static int
schedtune_boostgroup_update(int idx, int boost)
{
struct boost_groups *bg;
int cur_boost_max;
int old_boost;
int cpu;
/* Update per CPU boost groups */
for_each_possible_cpu(cpu) {
bg = &per_cpu(cpu_boost_groups, cpu);
/* CGroups are never associated to non active cgroups */
BUG_ON(!bg->group[idx].valid);
/*
* Keep track of current boost values to compute the per CPU
* maximum only when it has been affected by the new value of
* the updated boost group
*/
cur_boost_max = bg->boost_max;
old_boost = bg->group[idx].boost;
/* Update the boost value of this boost group */
bg->group[idx].boost = 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) {
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 = &per_cpu(cpu_boost_groups, cpu);
int tasks = bg->group[idx].tasks + task_count;
/* Update boosted tasks count while avoiding to make it negative */
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 */
if (tasks == 1 || tasks == 0)
schedtune_cpu_update(cpu);
}
/*
* NOTE: This function must be called while holding the lock on the CPU RQ
*/
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.
* Thus we avoid any further update, since we do not want to change
* CPU boosting while the task is exiting.
*/
if (p->flags & PF_EXITING)
return;
/*
* 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);
}
int schedtune_can_attach(struct cgroup_taskset *tset)
{
struct task_struct *task;
struct cgroup_subsys_state *css;
struct boost_groups *bg;
struct rq_flags 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");
}
/*
* NOTE: This function must be called while holding the lock on the CPU RQ
*/
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 is already enforce by the do_exit() code path
* via schedtune_exit_task().
*/
if (p->flags & PF_EXITING)
return;
/*
* 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;
struct rq_flags 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();
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)
{
struct boost_groups *bg;
bg = &per_cpu(cpu_boost_groups, cpu);
return bg->boost_max;
}
int schedtune_task_boost(struct task_struct *p)
{
struct schedtune *st;
int task_boost;
if (!unlikely(schedtune_initialized))
return 0;
/* 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;
if (!unlikely(schedtune_initialized))
return 0;
/* 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);
return st->boost;
}
static int
boost_write(struct cgroup_subsys_state *css, struct cftype *cft,
s64 boost)
{
struct schedtune *st = css_st(css);
unsigned threshold_idx;
int boost_pct;
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) {
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_s64 = boost_read,
.write_s64 = boost_write,
},
{
.name = "prefer_idle",
.read_u64 = prefer_idle_read,
.write_u64 = prefer_idle_write,
},
{ } /* terminate */
};
static void
schedtune_boostgroup_init(struct schedtune *st, int idx)
{
struct boost_groups *bg;
int cpu;
/* Initialize per CPUs boost group support */
for_each_possible_cpu(cpu) {
bg = &per_cpu(cpu_boost_groups, cpu);
bg->group[idx].boost = 0;
bg->group[idx].valid = true;
}
/* Keep track of allocated boost groups */
allocated_group[idx] = st;
st->idx = idx;
}
static struct cgroup_subsys_state *
schedtune_css_alloc(struct cgroup_subsys_state *parent_css)
{
struct schedtune *st;
int idx;
if (!parent_css)
return &root_schedtune.css;
/* Allow only single level hierachies */
if (parent_css != &root_schedtune.css) {
pr_err("Nested SchedTune boosting groups not allowed\n");
return ERR_PTR(-ENOMEM);
}
/* Allow only a limited number of boosting groups */
for (idx = 1; idx < BOOSTGROUPS_COUNT; ++idx)
if (!allocated_group[idx])
break;
if (idx == BOOSTGROUPS_COUNT) {
pr_err("Trying to create more than %d SchedTune boosting groups\n",
BOOSTGROUPS_COUNT);
return ERR_PTR(-ENOSPC);
}
st = kzalloc(sizeof(*st), GFP_KERNEL);
if (!st)
goto out;
/* Initialize per CPUs boost group support */
schedtune_boostgroup_init(st, idx);
return &st->css;
out:
return ERR_PTR(-ENOMEM);
}
static void
schedtune_boostgroup_release(struct schedtune *st)
{
struct boost_groups *bg;
int cpu;
/* Reset per CPUs boost group support */
for_each_possible_cpu(cpu) {
bg = &per_cpu(cpu_boost_groups, cpu);
bg->group[st->idx].valid = false;
bg->group[st->idx].boost = 0;
}
/* Keep track of allocated boost groups */
allocated_group[st->idx] = NULL;
}
static void
schedtune_css_free(struct cgroup_subsys_state *css)
{
struct schedtune *st = css_st(css);
/* Release per CPUs boost group support */
schedtune_boostgroup_release(st);
kfree(st);
}
struct cgroup_subsys schedtune_cgrp_subsys = {
.css_alloc = schedtune_css_alloc,
.css_free = schedtune_css_free,
.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));
bg->group[0].valid = true;
raw_spin_lock_init(&bg->lock);
}
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
sysctl_sched_cfs_boost_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
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_CAPACITY_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
schedtune_spc_rdiv = reciprocal_value(100);
return 0;
nodata:
pr_warning("schedtune: disabled!\n");
rcu_read_unlock();
return -EINVAL;
}
postcore_initcall(schedtune_init);