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PM / EM: add support for other devices than CPUs in Energy Model

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Add support for other devices than CPUs. The registration function
does not require a valid cpumask pointer and is ready to handle new
devices. Some of the internal structures has been reorganized in order to
keep consistent view (like removing per_cpu pd pointers).

Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Lukasz Luba 2020-06-10 11:12:23 +01:00 committed by Rafael J. Wysocki
parent d0351cc3b0
commit 1bc138c622
3 changed files with 199 additions and 89 deletions
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5
include/linux/device.h
View File

@ -13,6 +13,7 @@
#define _DEVICE_H_
#include <linux/dev_printk.h>
#include <linux/energy_model.h>
#include <linux/ioport.h>
#include <linux/kobject.h>
#include <linux/klist.h>
@ -559,6 +560,10 @@ struct device {
struct dev_pm_info power;
struct dev_pm_domain *pm_domain;
#ifdef CONFIG_ENERGY_MODEL
struct em_perf_domain *em_pd;
#endif
#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
struct irq_domain *msi_domain;
#endif

29
include/linux/energy_model.h
View File

@ -12,8 +12,10 @@
/**
* em_perf_state - Performance state of a performance domain
* @frequency: The CPU frequency in KHz, for consistency with CPUFreq
* @power: The power consumed by 1 CPU at this level, in milli-watts
* @frequency: The frequency in KHz, for consistency with CPUFreq
* @power: The power consumed at this level, in milli-watts (by 1 CPU or
by a registered device). It can be a total power: static and
dynamic.
* @cost: The cost coefficient associated with this level, used during
* energy calculation. Equal to: power * max_frequency / frequency
*/
@ -27,12 +29,16 @@ struct em_perf_state {
* em_perf_domain - Performance domain
* @table: List of performance states, in ascending order
* @nr_perf_states: Number of performance states
* @cpus: Cpumask covering the CPUs of the domain
* @cpus: Cpumask covering the CPUs of the domain. It's here
* for performance reasons to avoid potential cache
* misses during energy calculations in the scheduler
* and simplifies allocating/freeing that memory region.
*
* A "performance domain" represents a group of CPUs whose performance is
* scaled together. All CPUs of a performance domain must have the same
* micro-architecture. Performance domains often have a 1-to-1 mapping with
* CPUFreq policies.
* In case of CPU device, a "performance domain" represents a group of CPUs
* whose performance is scaled together. All CPUs of a performance domain
* must have the same micro-architecture. Performance domains often have
* a 1-to-1 mapping with CPUFreq policies. In case of other devices the @cpus
* field is unused.
*/
struct em_perf_domain {
struct em_perf_state *table;
@ -71,10 +77,12 @@ struct em_data_callback {
#define EM_DATA_CB(_active_power_cb) { .active_power = &_active_power_cb }
struct em_perf_domain *em_cpu_get(int cpu);
struct em_perf_domain *em_pd_get(struct device *dev);
int em_register_perf_domain(cpumask_t *span, unsigned int nr_states,
struct em_data_callback *cb);
int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
struct em_data_callback *cb, cpumask_t *span);
void em_dev_unregister_perf_domain(struct device *dev);
/**
* em_pd_energy() - Estimates the energy consumed by the CPUs of a perf. domain
@ -184,10 +192,17 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
{
return -EINVAL;
}
static inline void em_dev_unregister_perf_domain(struct device *dev)
{
}
static inline struct em_perf_domain *em_cpu_get(int cpu)
{
return NULL;
}
static inline struct em_perf_domain *em_pd_get(struct device *dev)
{
return NULL;
}
static inline unsigned long em_pd_energy(struct em_perf_domain *pd,
unsigned long max_util, unsigned long sum_util)
{

254
kernel/power/energy_model.c
View File

@ -1,9 +1,10 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Energy Model of CPUs
* Energy Model of devices
*
* Copyright (c) 2018, Arm ltd.
* Copyright (c) 2018-2020, Arm ltd.
* Written by: Quentin Perret, Arm ltd.
* Improvements provided by: Lukasz Luba, Arm ltd.
*/
#define pr_fmt(fmt) "energy_model: " fmt
@ -15,15 +16,17 @@
#include <linux/sched/topology.h>
#include <linux/slab.h>
/* Mapping of each CPU to the performance domain to which it belongs. */
static DEFINE_PER_CPU(struct em_perf_domain *, em_data);
/*
* Mutex serializing the registrations of performance domains and letting
* callbacks defined by drivers sleep.
*/
static DEFINE_MUTEX(em_pd_mutex);
static bool _is_cpu_device(struct device *dev)
{
return (dev->bus == &cpu_subsys);
}
#ifdef CONFIG_DEBUG_FS
static struct dentry *rootdir;
@ -49,22 +52,30 @@ static int em_debug_cpus_show(struct seq_file *s, void *unused)
}
DEFINE_SHOW_ATTRIBUTE(em_debug_cpus);
static void em_debug_create_pd(struct em_perf_domain *pd, int cpu)
static void em_debug_create_pd(struct device *dev)
{
struct dentry *d;
char name[8];
int i;
snprintf(name, sizeof(name), "pd%d", cpu);
/* Create the directory of the performance domain */
d = debugfs_create_dir(name, rootdir);
d = debugfs_create_dir(dev_name(dev), rootdir);
debugfs_create_file("cpus", 0444, d, pd->cpus, &em_debug_cpus_fops);
if (_is_cpu_device(dev))
debugfs_create_file("cpus", 0444, d, dev->em_pd->cpus,
&em_debug_cpus_fops);
/* Create a sub-directory for each performance state */
for (i = 0; i < pd->nr_perf_states; i++)
em_debug_create_ps(&pd->table[i], d);
for (i = 0; i < dev->em_pd->nr_perf_states; i++)
em_debug_create_ps(&dev->em_pd->table[i], d);
}
static void em_debug_remove_pd(struct device *dev)
{
struct dentry *debug_dir;
debug_dir = debugfs_lookup(dev_name(dev), rootdir);
debugfs_remove_recursive(debug_dir);
}
static int __init em_debug_init(void)
@ -76,40 +87,34 @@ static int __init em_debug_init(void)
}
core_initcall(em_debug_init);
#else /* CONFIG_DEBUG_FS */
static void em_debug_create_pd(struct em_perf_domain *pd, int cpu) {}
static void em_debug_create_pd(struct device *dev) {}
static void em_debug_remove_pd(struct device *dev) {}
#endif
static struct em_perf_domain *
em_create_pd(struct device *dev, int nr_states, struct em_data_callback *cb,
cpumask_t *span)
static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd,
int nr_states, struct em_data_callback *cb)
{
unsigned long opp_eff, prev_opp_eff = ULONG_MAX;
unsigned long power, freq, prev_freq = 0;
int i, ret, cpu = cpumask_first(span);
struct em_perf_state *table;
struct em_perf_domain *pd;
int i, ret;
u64 fmax;
if (!cb->active_power)
return NULL;
pd = kzalloc(sizeof(*pd) + cpumask_size(), GFP_KERNEL);
if (!pd)
return NULL;
table = kcalloc(nr_states, sizeof(*table), GFP_KERNEL);
if (!table)
goto free_pd;
return -ENOMEM;
/* Build the list of performance states for this performance domain */
for (i = 0, freq = 0; i < nr_states; i++, freq++) {
/*
* active_power() is a driver callback which ceils 'freq' to
* lowest performance state of 'cpu' above 'freq' and updates
* lowest performance state of 'dev' above 'freq' and updates
* 'power' and 'freq' accordingly.
*/
ret = cb->active_power(&power, &freq, dev);
if (ret) {
pr_err("pd%d: invalid perf. state: %d\n", cpu, ret);
dev_err(dev, "EM: invalid perf. state: %d\n",
ret);
goto free_ps_table;
}
@ -118,7 +123,8 @@ em_create_pd(struct device *dev, int nr_states, struct em_data_callback *cb,
* higher performance states.
*/
if (freq <= prev_freq) {
pr_err("pd%d: non-increasing freq: %lu\n", cpu, freq);
dev_err(dev, "EM: non-increasing freq: %lu\n",
freq);
goto free_ps_table;
}
@ -127,7 +133,8 @@ em_create_pd(struct device *dev, int nr_states, struct em_data_callback *cb,
* positive, in milli-watts and to fit into 16 bits.
*/
if (!power || power > EM_MAX_POWER) {
pr_err("pd%d: invalid power: %lu\n", cpu, power);
dev_err(dev, "EM: invalid power: %lu\n",
power);
goto free_ps_table;
}
@ -142,8 +149,8 @@ em_create_pd(struct device *dev, int nr_states, struct em_data_callback *cb,
*/
opp_eff = freq / power;
if (opp_eff >= prev_opp_eff)
pr_warn("pd%d: hertz/watts ratio non-monotonically decreasing: em_perf_state %d >= em_perf_state%d\n",
cpu, i, i - 1);
dev_dbg(dev, "EM: hertz/watts ratio non-monotonically decreasing: em_perf_state %d >= em_perf_state%d\n",
i, i - 1);
prev_opp_eff = opp_eff;
}
@ -156,30 +163,82 @@ em_create_pd(struct device *dev, int nr_states, struct em_data_callback *cb,
pd->table = table;
pd->nr_perf_states = nr_states;
cpumask_copy(to_cpumask(pd->cpus), span);
em_debug_create_pd(pd, cpu);
return pd;
return 0;
free_ps_table:
kfree(table);
free_pd:
kfree(pd);
return NULL;
return -EINVAL;
}
static int em_create_pd(struct device *dev, int nr_states,
struct em_data_callback *cb, cpumask_t *cpus)
{
struct em_perf_domain *pd;
struct device *cpu_dev;
int cpu, ret;
if (_is_cpu_device(dev)) {
pd = kzalloc(sizeof(*pd) + cpumask_size(), GFP_KERNEL);
if (!pd)
return -ENOMEM;
cpumask_copy(em_span_cpus(pd), cpus);
} else {
pd = kzalloc(sizeof(*pd), GFP_KERNEL);
if (!pd)
return -ENOMEM;
}
ret = em_create_perf_table(dev, pd, nr_states, cb);
if (ret) {
kfree(pd);
return ret;
}
if (_is_cpu_device(dev))
for_each_cpu(cpu, cpus) {
cpu_dev = get_cpu_device(cpu);
cpu_dev->em_pd = pd;
}
dev->em_pd = pd;
return 0;
}
/**
* em_pd_get() - Return the performance domain for a device
* @dev : Device to find the performance domain for
*
* Returns the performance domain to which @dev belongs, or NULL if it doesn't
* exist.
*/
struct em_perf_domain *em_pd_get(struct device *dev)
{
if (IS_ERR_OR_NULL(dev))
return NULL;
return dev->em_pd;
}
EXPORT_SYMBOL_GPL(em_pd_get);
/**
* em_cpu_get() - Return the performance domain for a CPU
* @cpu : CPU to find the performance domain for
*
* Return: the performance domain to which 'cpu' belongs, or NULL if it doesn't
* Returns the performance domain to which @cpu belongs, or NULL if it doesn't
* exist.
*/
struct em_perf_domain *em_cpu_get(int cpu)
{
return READ_ONCE(per_cpu(em_data, cpu));
struct device *cpu_dev;
cpu_dev = get_cpu_device(cpu);
if (!cpu_dev)
return NULL;
return em_pd_get(cpu_dev);
}
EXPORT_SYMBOL_GPL(em_cpu_get);
@ -188,7 +247,7 @@ EXPORT_SYMBOL_GPL(em_cpu_get);
* @dev : Device for which the EM is to register
* @nr_states : Number of performance states to register
* @cb : Callback functions providing the data of the Energy Model
* @span : Pointer to cpumask_t, which in case of a CPU device is
* @cpus : Pointer to cpumask_t, which in case of a CPU device is
* obligatory. It can be taken from i.e. 'policy->cpus'. For other
* type of devices this should be set to NULL.
*
@ -201,13 +260,12 @@ EXPORT_SYMBOL_GPL(em_cpu_get);
* Return 0 on success
*/
int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
struct em_data_callback *cb, cpumask_t *span)
struct em_data_callback *cb, cpumask_t *cpus)
{
unsigned long cap, prev_cap = 0;
struct em_perf_domain *pd;
int cpu, ret = 0;
int cpu, ret;
if (!dev || !span || !nr_states || !cb)
if (!dev || !nr_states || !cb)
return -EINVAL;
/*
@ -216,47 +274,50 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
*/
mutex_lock(&em_pd_mutex);
for_each_cpu(cpu, span) {
/* Make sure we don't register again an existing domain. */
if (READ_ONCE(per_cpu(em_data, cpu))) {
ret = -EEXIST;
goto unlock;
}
/*
* All CPUs of a domain must have the same micro-architecture
* since they all share the same table.
*/
cap = arch_scale_cpu_capacity(cpu);
if (prev_cap && prev_cap != cap) {
pr_err("CPUs of %*pbl must have the same capacity\n",
cpumask_pr_args(span));
ret = -EINVAL;
goto unlock;
}
prev_cap = cap;
}
/* Create the performance domain and add it to the Energy Model. */
pd = em_create_pd(dev, nr_states, cb, span);
if (!pd) {
ret = -EINVAL;
if (dev->em_pd) {
ret = -EEXIST;
goto unlock;
}
for_each_cpu(cpu, span) {
/*
* The per-cpu array can be read concurrently from em_cpu_get().
* The barrier enforces the ordering needed to make sure readers
* can only access well formed em_perf_domain structs.
*/
smp_store_release(per_cpu_ptr(&em_data, cpu), pd);
if (_is_cpu_device(dev)) {
if (!cpus) {
dev_err(dev, "EM: invalid CPU mask\n");
ret = -EINVAL;
goto unlock;
}
for_each_cpu(cpu, cpus) {
if (em_cpu_get(cpu)) {
dev_err(dev, "EM: exists for CPU%d\n", cpu);
ret = -EEXIST;
goto unlock;
}
/*
* All CPUs of a domain must have the same
* micro-architecture since they all share the same
* table.
*/
cap = arch_scale_cpu_capacity(cpu);
if (prev_cap && prev_cap != cap) {
dev_err(dev, "EM: CPUs of %*pbl must have the same capacity\n",
cpumask_pr_args(cpus));
ret = -EINVAL;
goto unlock;
}
prev_cap = cap;
}
}
pr_debug("Created perf domain %*pbl\n", cpumask_pr_args(span));
ret = em_create_pd(dev, nr_states, cb, cpus);
if (ret)
goto unlock;
em_debug_create_pd(dev);
dev_info(dev, "EM: created perf domain\n");
unlock:
mutex_unlock(&em_pd_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(em_dev_register_perf_domain);
@ -285,3 +346,32 @@ int em_register_perf_domain(cpumask_t *span, unsigned int nr_states,
return em_dev_register_perf_domain(cpu_dev, nr_states, cb, span);
}
EXPORT_SYMBOL_GPL(em_register_perf_domain);
/**
* em_dev_unregister_perf_domain() - Unregister Energy Model (EM) for a device
* @dev : Device for which the EM is registered
*
* Unregister the EM for the specified @dev (but not a CPU device).
*/
void em_dev_unregister_perf_domain(struct device *dev)
{
if (IS_ERR_OR_NULL(dev) || !dev->em_pd)
return;
if (_is_cpu_device(dev))
return;
/*
* The mutex separates all register/unregister requests and protects
* from potential clean-up/setup issues in the debugfs directories.
* The debugfs directory name is the same as device's name.
*/
mutex_lock(&em_pd_mutex);
em_debug_remove_pd(dev);
kfree(dev->em_pd->table);
kfree(dev->em_pd);
dev->em_pd = NULL;
mutex_unlock(&em_pd_mutex);
}
EXPORT_SYMBOL_GPL(em_dev_unregister_perf_domain);