[linux-2.6-block.git] / include / linux / energy_model.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_ENERGY_MODEL_H
#define _LINUX_ENERGY_MODEL_H
#include <linux/cpumask.h>
#include <linux/device.h>
#include <linux/jump_label.h>
#include <linux/kobject.h>
#include <linux/kref.h>
#include <linux/rcupdate.h>
#include <linux/sched/cpufreq.h>
#include <linux/sched/topology.h>
#include <linux/types.h>

/**
 * struct em_perf_state - Performance state of a performance domain
 * @performance:	CPU performance (capacity) at a given frequency
 * @frequency:	The frequency in KHz, for consistency with CPUFreq
 * @power:	The power consumed at this level (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
 * @flags:	see "em_perf_state flags" description below.
 */
struct em_perf_state {
	unsigned long performance;
	unsigned long frequency;
	unsigned long power;
	unsigned long cost;
	unsigned long flags;
};

/*
 * em_perf_state flags:
 *
 * EM_PERF_STATE_INEFFICIENT: The performance state is inefficient. There is
 * in this em_perf_domain, another performance state with a higher frequency
 * but a lower or equal power cost. Such inefficient states are ignored when
 * using em_pd_get_efficient_*() functions.
 */
#define EM_PERF_STATE_INEFFICIENT BIT(0)

/**
 * struct em_perf_table - Performance states table
 * @rcu:	RCU used for safe access and destruction
 * @kref:	Reference counter to track the users
 * @state:	List of performance states, in ascending order
 */
struct em_perf_table {
	struct rcu_head rcu;
	struct kref kref;
	struct em_perf_state state[];
};

/**
 * struct em_perf_domain - Performance domain
 * @em_table:		Pointer to the runtime modifiable em_perf_table
 * @nr_perf_states:	Number of performance states
 * @flags:		See "em_perf_domain flags"
 * @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.
 *
 * 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_table __rcu *em_table;
	int nr_perf_states;
	unsigned long flags;
	unsigned long cpus[];
};

/*
 *  em_perf_domain flags:
 *
 *  EM_PERF_DOMAIN_MICROWATTS: The power values are in micro-Watts or some
 *  other scale.
 *
 *  EM_PERF_DOMAIN_SKIP_INEFFICIENCIES: Skip inefficient states when estimating
 *  energy consumption.
 *
 *  EM_PERF_DOMAIN_ARTIFICIAL: The power values are artificial and might be
 *  created by platform missing real power information
 */
#define EM_PERF_DOMAIN_MICROWATTS BIT(0)
#define EM_PERF_DOMAIN_SKIP_INEFFICIENCIES BIT(1)
#define EM_PERF_DOMAIN_ARTIFICIAL BIT(2)

#define em_span_cpus(em) (to_cpumask((em)->cpus))
#define em_is_artificial(em) ((em)->flags & EM_PERF_DOMAIN_ARTIFICIAL)

#ifdef CONFIG_ENERGY_MODEL
/*
 * The max power value in micro-Watts. The limit of 64 Watts is set as
 * a safety net to not overflow multiplications on 32bit platforms. The
 * 32bit value limit for total Perf Domain power implies a limit of
 * maximum CPUs in such domain to 64.
 */
#define EM_MAX_POWER (64000000) /* 64 Watts */

/*
 * To avoid possible energy estimation overflow on 32bit machines add
 * limits to number of CPUs in the Perf. Domain.
 * We are safe on 64bit machine, thus some big number.
 */
#ifdef CONFIG_64BIT
#define EM_MAX_NUM_CPUS 4096
#else
#define EM_MAX_NUM_CPUS 16
#endif

struct em_data_callback {
	/**
	 * active_power() - Provide power at the next performance state of
	 *		a device
	 * @dev		: Device for which we do this operation (can be a CPU)
	 * @power	: Active power at the performance state
	 *		(modified)
	 * @freq	: Frequency at the performance state in kHz
	 *		(modified)
	 *
	 * active_power() must find the lowest performance state of 'dev' above
	 * 'freq' and update 'power' and 'freq' to the matching active power
	 * and frequency.
	 *
	 * In case of CPUs, the power is the one of a single CPU in the domain,
	 * expressed in micro-Watts or an abstract scale. It is expected to
	 * fit in the [0, EM_MAX_POWER] range.
	 *
	 * Return 0 on success.
	 */
	int (*active_power)(struct device *dev, unsigned long *power,
			    unsigned long *freq);

	/**
	 * get_cost() - Provide the cost at the given performance state of
	 *		a device
	 * @dev		: Device for which we do this operation (can be a CPU)
	 * @freq	: Frequency at the performance state in kHz
	 * @cost	: The cost value for the performance state
	 *		(modified)
	 *
	 * In case of CPUs, the cost is the one of a single CPU in the domain.
	 * It is expected to fit in the [0, EM_MAX_POWER] range due to internal
	 * usage in EAS calculation.
	 *
	 * Return 0 on success, or appropriate error value in case of failure.
	 */
	int (*get_cost)(struct device *dev, unsigned long freq,
			unsigned long *cost);
};
#define EM_SET_ACTIVE_POWER_CB(em_cb, cb) ((em_cb).active_power = cb)
#define EM_ADV_DATA_CB(_active_power_cb, _cost_cb)	\
	{ .active_power = _active_power_cb,		\
	  .get_cost = _cost_cb }
#define EM_DATA_CB(_active_power_cb)			\
		EM_ADV_DATA_CB(_active_power_cb, NULL)

struct em_perf_domain *em_cpu_get(int cpu);
struct em_perf_domain *em_pd_get(struct device *dev);
int em_dev_update_perf_domain(struct device *dev,
			      struct em_perf_table __rcu *new_table);
int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
				struct em_data_callback *cb, cpumask_t *span,
				bool microwatts);
void em_dev_unregister_perf_domain(struct device *dev);
struct em_perf_table __rcu *em_table_alloc(struct em_perf_domain *pd);
void em_table_free(struct em_perf_table __rcu *table);
int em_dev_compute_costs(struct device *dev, struct em_perf_state *table,
			 int nr_states);

/**
 * em_pd_get_efficient_state() - Get an efficient performance state from the EM
 * @table:		List of performance states, in ascending order
 * @nr_perf_states:	Number of performance states
 * @max_util:		Max utilization to map with the EM
 * @pd_flags:		Performance Domain flags
 *
 * It is called from the scheduler code quite frequently and as a consequence
 * doesn't implement any check.
 *
 * Return: An efficient performance state id, high enough to meet @max_util
 * requirement.
 */
static inline int
em_pd_get_efficient_state(struct em_perf_state *table, int nr_perf_states,
			  unsigned long max_util, unsigned long pd_flags)
{
	struct em_perf_state *ps;
	int i;

	for (i = 0; i < nr_perf_states; i++) {
		ps = &table[i];
		if (ps->performance >= max_util) {
			if (pd_flags & EM_PERF_DOMAIN_SKIP_INEFFICIENCIES &&
			    ps->flags & EM_PERF_STATE_INEFFICIENT)
				continue;
			return i;
		}
	}

	return nr_perf_states - 1;
}

/**
 * em_cpu_energy() - Estimates the energy consumed by the CPUs of a
 *		performance domain
 * @pd		: performance domain for which energy has to be estimated
 * @max_util	: highest utilization among CPUs of the domain
 * @sum_util	: sum of the utilization of all CPUs in the domain
 * @allowed_cpu_cap	: maximum allowed CPU capacity for the @pd, which
 *			  might reflect reduced frequency (due to thermal)
 *
 * This function must be used only for CPU devices. There is no validation,
 * i.e. if the EM is a CPU type and has cpumask allocated. It is called from
 * the scheduler code quite frequently and that is why there is not checks.
 *
 * Return: the sum of the energy consumed by the CPUs of the domain assuming
 * a capacity state satisfying the max utilization of the domain.
 */
static inline unsigned long em_cpu_energy(struct em_perf_domain *pd,
				unsigned long max_util, unsigned long sum_util,
				unsigned long allowed_cpu_cap)
{
	struct em_perf_table *em_table;
	struct em_perf_state *ps;
	int i;

#ifdef CONFIG_SCHED_DEBUG
	WARN_ONCE(!rcu_read_lock_held(), "EM: rcu read lock needed\n");
#endif

	if (!sum_util)
		return 0;

	/*
	 * In order to predict the performance state, map the utilization of
	 * the most utilized CPU of the performance domain to a requested
	 * performance, like schedutil. Take also into account that the real
	 * performance might be set lower (due to thermal capping). Thus, clamp
	 * max utilization to the allowed CPU capacity before calculating
	 * effective performance.
	 */
	max_util = map_util_perf(max_util);
	max_util = min(max_util, allowed_cpu_cap);

	/*
	 * Find the lowest performance state of the Energy Model above the
	 * requested performance.
	 */
	em_table = rcu_dereference(pd->em_table);
	i = em_pd_get_efficient_state(em_table->state, pd->nr_perf_states,
				      max_util, pd->flags);
	ps = &em_table->state[i];

	/*
	 * The performance (capacity) of a CPU in the domain at the performance
	 * state (ps) can be computed as:
	 *
	 *                     ps->freq * scale_cpu
	 *   ps->performance = --------------------                  (1)
	 *                         cpu_max_freq
	 *
	 * So, ignoring the costs of idle states (which are not available in
	 * the EM), the energy consumed by this CPU at that performance state
	 * is estimated as:
	 *
	 *             ps->power * cpu_util
	 *   cpu_nrg = --------------------                          (2)
	 *               ps->performance
	 *
	 * since 'cpu_util / ps->performance' represents its percentage of busy
	 * time.
	 *
	 *   NOTE: Although the result of this computation actually is in
	 *         units of power, it can be manipulated as an energy value
	 *         over a scheduling period, since it is assumed to be
	 *         constant during that interval.
	 *
	 * By injecting (1) in (2), 'cpu_nrg' can be re-expressed as a product
	 * of two terms:
	 *
	 *             ps->power * cpu_max_freq
	 *   cpu_nrg = ------------------------ * cpu_util           (3)
	 *               ps->freq * scale_cpu
	 *
	 * The first term is static, and is stored in the em_perf_state struct
	 * as 'ps->cost'.
	 *
	 * Since all CPUs of the domain have the same micro-architecture, they
	 * share the same 'ps->cost', and the same CPU capacity. Hence, the
	 * total energy of the domain (which is the simple sum of the energy of
	 * all of its CPUs) can be factorized as:
	 *
	 *   pd_nrg = ps->cost * \Sum cpu_util                       (4)
	 */
	return ps->cost * sum_util;
}

/**
 * em_pd_nr_perf_states() - Get the number of performance states of a perf.
 *				domain
 * @pd		: performance domain for which this must be done
 *
 * Return: the number of performance states in the performance domain table
 */
static inline int em_pd_nr_perf_states(struct em_perf_domain *pd)
{
	return pd->nr_perf_states;
}

/**
 * em_perf_state_from_pd() - Get the performance states table of perf.
 *				domain
 * @pd		: performance domain for which this must be done
 *
 * To use this function the rcu_read_lock() should be hold. After the usage
 * of the performance states table is finished, the rcu_read_unlock() should
 * be called.
 *
 * Return: the pointer to performance states table of the performance domain
 */
static inline
struct em_perf_state *em_perf_state_from_pd(struct em_perf_domain *pd)
{
	return rcu_dereference(pd->em_table)->state;
}

#else
struct em_data_callback {};
#define EM_ADV_DATA_CB(_active_power_cb, _cost_cb) { }
#define EM_DATA_CB(_active_power_cb) { }
#define EM_SET_ACTIVE_POWER_CB(em_cb, cb) do { } while (0)

static inline
int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
				struct em_data_callback *cb, cpumask_t *span,
				bool microwatts)
{
	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_cpu_energy(struct em_perf_domain *pd,
			unsigned long max_util, unsigned long sum_util,
			unsigned long allowed_cpu_cap)
{
	return 0;
}
static inline int em_pd_nr_perf_states(struct em_perf_domain *pd)
{
	return 0;
}
static inline
struct em_perf_table __rcu *em_table_alloc(struct em_perf_domain *pd)
{
	return NULL;
}
static inline void em_table_free(struct em_perf_table __rcu *table) {}
static inline
int em_dev_update_perf_domain(struct device *dev,
			      struct em_perf_table __rcu *new_table)
{
	return -EINVAL;
}
static inline
struct em_perf_state *em_perf_state_from_pd(struct em_perf_domain *pd)
{
	return NULL;
}
static inline
int em_dev_compute_costs(struct device *dev, struct em_perf_state *table,
			 int nr_states)
{
	return -EINVAL;
}
#endif

#endif
Commit	Line	Data
27871f7a QP	1	/* SPDX-License-Identifier: GPL-2.0 */
	2	#ifndef _LINUX_ENERGY_MODEL_H
	3	#define _LINUX_ENERGY_MODEL_H
	4	#include <linux/cpumask.h>
7d9895c7	5	#include <linux/device.h>
27871f7a QP	6	#include <linux/jump_label.h>
27871f7a QP	7	#include <linux/kobject.h>
ffcf9bce	8	#include <linux/kref.h>
27871f7a QP	9	#include <linux/rcupdate.h>
	10	#include <linux/sched/cpufreq.h>
	11	#include <linux/sched/topology.h>
	12	#include <linux/types.h>
	13
27871f7a	14	/**
ca67408a	15	* struct em_perf_state - Performance state of a performance domain
5a367f7b	16	* @performance: CPU performance (capacity) at a given frequency
1bc138c6	17	* @frequency: The frequency in KHz, for consistency with CPUFreq
f2c90b12 LL	18	* @power: The power consumed at this level (by 1 CPU or by a registered
f2c90b12 LL	19	* device). It can be a total power: static and dynamic.
27871f7a QP	20	* @cost: The cost coefficient associated with this level, used during
27871f7a QP	21	* energy calculation. Equal to: power * max_frequency / frequency
c8ed9953	22	* @flags: see "em_perf_state flags" description below.
27871f7a	23	*/
521b512b	24	struct em_perf_state {
5a367f7b	25	unsigned long performance;
27871f7a QP	26	unsigned long frequency;
	27	unsigned long power;
	28	unsigned long cost;
c8ed9953	29	unsigned long flags;
27871f7a QP	30	};
27871f7a QP	31
c8ed9953 VD	32	/*
	33	* em_perf_state flags:
	34	*
	35	* EM_PERF_STATE_INEFFICIENT: The performance state is inefficient. There is
	36	* in this em_perf_domain, another performance state with a higher frequency
	37	* but a lower or equal power cost. Such inefficient states are ignored when
	38	* using em_pd_get_efficient_*() functions.
	39	*/
	40	#define EM_PERF_STATE_INEFFICIENT BIT(0)
	41
ca0fc871 LL	42	/**
	43	* struct em_perf_table - Performance states table
	44	* @rcu: RCU used for safe access and destruction
ffcf9bce	45	* @kref: Reference counter to track the users
ca0fc871 LL	46	* @state: List of performance states, in ascending order
	47	*/
	48	struct em_perf_table {
	49	struct rcu_head rcu;
ffcf9bce	50	struct kref kref;
ca0fc871 LL	51	struct em_perf_state state[];
	52	};
	53
27871f7a	54	/**
ca67408a	55	* struct em_perf_domain - Performance domain
ca0fc871	56	* @em_table: Pointer to the runtime modifiable em_perf_table
521b512b	57	* @nr_perf_states: Number of performance states
88f7a895	58	* @flags: See "em_perf_domain flags"
1bc138c6 LL	59	* @cpus: Cpumask covering the CPUs of the domain. It's here
	60	* for performance reasons to avoid potential cache
	61	* misses during energy calculations in the scheduler
	62	* and simplifies allocating/freeing that memory region.
27871f7a	63	*
1bc138c6 LL	64	* In case of CPU device, a "performance domain" represents a group of CPUs
	65	* whose performance is scaled together. All CPUs of a performance domain
	66	* must have the same micro-architecture. Performance domains often have
	67	* a 1-to-1 mapping with CPUFreq policies. In case of other devices the @cpus
	68	* field is unused.
27871f7a QP	69	*/
27871f7a QP	70	struct em_perf_domain {
ca0fc871	71	struct em_perf_table __rcu *em_table;
521b512b	72	int nr_perf_states;
88f7a895	73	unsigned long flags;
beb69f15	74	unsigned long cpus[];
27871f7a QP	75	};
27871f7a QP	76
88f7a895 VD	77	/*
	78	* em_perf_domain flags:
	79	*
ae6ccaa6	80	* EM_PERF_DOMAIN_MICROWATTS: The power values are in micro-Watts or some
88f7a895	81	* other scale.
8354eb9e VD	82	*
	83	* EM_PERF_DOMAIN_SKIP_INEFFICIENCIES: Skip inefficient states when estimating
	84	* energy consumption.
fc3a9a98 PG	85	*
	86	* EM_PERF_DOMAIN_ARTIFICIAL: The power values are artificial and might be
	87	* created by platform missing real power information
88f7a895	88	*/
ae6ccaa6	89	#define EM_PERF_DOMAIN_MICROWATTS BIT(0)
8354eb9e	90	#define EM_PERF_DOMAIN_SKIP_INEFFICIENCIES BIT(1)
fc3a9a98	91	#define EM_PERF_DOMAIN_ARTIFICIAL BIT(2)
88f7a895	92
521b512b	93	#define em_span_cpus(em) (to_cpumask((em)->cpus))
fc3a9a98	94	#define em_is_artificial(em) ((em)->flags & EM_PERF_DOMAIN_ARTIFICIAL)
521b512b	95
27a47e42	96	#ifdef CONFIG_ENERGY_MODEL
ae6ccaa6 LL	97	/*
	98	* The max power value in micro-Watts. The limit of 64 Watts is set as
	99	* a safety net to not overflow multiplications on 32bit platforms. The
	100	* 32bit value limit for total Perf Domain power implies a limit of
	101	* maximum CPUs in such domain to 64.
	102	*/
	103	#define EM_MAX_POWER (64000000) /* 64 Watts */
	104
	105	/*
	106	* To avoid possible energy estimation overflow on 32bit machines add
	107	* limits to number of CPUs in the Perf. Domain.
	108	* We are safe on 64bit machine, thus some big number.
	109	*/
	110	#ifdef CONFIG_64BIT
	111	#define EM_MAX_NUM_CPUS 4096
	112	#else
	113	#define EM_MAX_NUM_CPUS 16
	114	#endif
27871f7a QP	115
	116	struct em_data_callback {
	117	/**
521b512b	118	* active_power() - Provide power at the next performance state of
d0351cc3	119	* a device
75a3a99a	120	* @dev : Device for which we do this operation (can be a CPU)
f2c90b12	121	* @power : Active power at the performance state
521b512b LL	122	* (modified)
	123	* @freq : Frequency at the performance state in kHz
	124	* (modified)
27871f7a	125	*
d0351cc3	126	* active_power() must find the lowest performance state of 'dev' above
27871f7a QP	127	* 'freq' and update 'power' and 'freq' to the matching active power
	128	* and frequency.
	129	*
d0351cc3	130	* In case of CPUs, the power is the one of a single CPU in the domain,
ae6ccaa6	131	* expressed in micro-Watts or an abstract scale. It is expected to
f2c90b12	132	* fit in the [0, EM_MAX_POWER] range.
27871f7a QP	133	*
	134	* Return 0 on success.
	135	*/
75a3a99a LL	136	int (active_power)(struct device dev, unsigned long *power,
75a3a99a LL	137	unsigned long *freq);
bdc21a4d LL	138
	139	/**
	140	* get_cost() - Provide the cost at the given performance state of
	141	* a device
	142	* @dev : Device for which we do this operation (can be a CPU)
	143	* @freq : Frequency at the performance state in kHz
	144	* @cost : The cost value for the performance state
	145	* (modified)
	146	*
	147	* In case of CPUs, the cost is the one of a single CPU in the domain.
	148	* It is expected to fit in the [0, EM_MAX_POWER] range due to internal
	149	* usage in EAS calculation.
	150	*
	151	* Return 0 on success, or appropriate error value in case of failure.
	152	*/
	153	int (get_cost)(struct device dev, unsigned long freq,
	154	unsigned long *cost);
27871f7a	155	};
caeea9e6	156	#define EM_SET_ACTIVE_POWER_CB(em_cb, cb) ((em_cb).active_power = cb)
bdc21a4d LL	157	#define EM_ADV_DATA_CB(_active_power_cb, _cost_cb) \
	158	{ .active_power = _active_power_cb, \
	159	.get_cost = _cost_cb }
	160	#define EM_DATA_CB(_active_power_cb) \
	161	EM_ADV_DATA_CB(_active_power_cb, NULL)
27871f7a QP	162
27871f7a QP	163	struct em_perf_domain *em_cpu_get(int cpu);
1bc138c6	164	struct em_perf_domain em_pd_get(struct device dev);
977230d5 LL	165	int em_dev_update_perf_domain(struct device *dev,
977230d5 LL	166	struct em_perf_table __rcu *new_table);
7d9895c7	167	int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
c250d50f	168	struct em_data_callback cb, cpumask_t span,
ae6ccaa6	169	bool microwatts);
1bc138c6	170	void em_dev_unregister_perf_domain(struct device *dev);
ffcf9bce LL	171	struct em_perf_table __rcu em_table_alloc(struct em_perf_domain pd);
ffcf9bce LL	172	void em_table_free(struct em_perf_table __rcu *table);
22ea0284 LL	173	int em_dev_compute_costs(struct device dev, struct em_perf_state table,
22ea0284 LL	174	int nr_states);
27871f7a	175
8354eb9e VD	176	/**
8354eb9e VD	177	* em_pd_get_efficient_state() - Get an efficient performance state from the EM
a3c78778 LL	178	* @table: List of performance states, in ascending order
a3c78778 LL	179	* @nr_perf_states: Number of performance states
5a367f7b	180	* @max_util: Max utilization to map with the EM
a3c78778	181	* @pd_flags: Performance Domain flags
8354eb9e VD	182	*
	183	* It is called from the scheduler code quite frequently and as a consequence
	184	* doesn't implement any check.
	185	*
5a367f7b	186	* Return: An efficient performance state id, high enough to meet @max_util
8354eb9e VD	187	* requirement.
8354eb9e VD	188	*/
a3c78778 LL	189	static inline int
a3c78778 LL	190	em_pd_get_efficient_state(struct em_perf_state *table, int nr_perf_states,
5a367f7b	191	unsigned long max_util, unsigned long pd_flags)
8354eb9e VD	192	{
	193	struct em_perf_state *ps;
	194	int i;
	195
a3c78778 LL	196	for (i = 0; i < nr_perf_states; i++) {
a3c78778 LL	197	ps = &table[i];
5a367f7b	198	if (ps->performance >= max_util) {
a3c78778	199	if (pd_flags & EM_PERF_DOMAIN_SKIP_INEFFICIENCIES &&
8354eb9e VD	200	ps->flags & EM_PERF_STATE_INEFFICIENT)
8354eb9e VD	201	continue;
a3c78778	202	return i;
8354eb9e VD	203	}
	204	}
	205
a3c78778	206	return nr_perf_states - 1;
8354eb9e VD	207	}
8354eb9e VD	208
27871f7a	209	/**
f0b56947	210	* em_cpu_energy() - Estimates the energy consumed by the CPUs of a
ca67408a	211	* performance domain
27871f7a QP	212	* @pd : performance domain for which energy has to be estimated
	213	* @max_util : highest utilization among CPUs of the domain
	214	* @sum_util : sum of the utilization of all CPUs in the domain
8f1b971b	215	* @allowed_cpu_cap : maximum allowed CPU capacity for the @pd, which
ca67408a	216	* might reflect reduced frequency (due to thermal)
27871f7a	217	*
f0b56947 LL	218	* This function must be used only for CPU devices. There is no validation,
	219	* i.e. if the EM is a CPU type and has cpumask allocated. It is called from
	220	* the scheduler code quite frequently and that is why there is not checks.
	221	*
27871f7a QP	222	* Return: the sum of the energy consumed by the CPUs of the domain assuming
	223	* a capacity state satisfying the max utilization of the domain.
	224	*/
f0b56947	225	static inline unsigned long em_cpu_energy(struct em_perf_domain *pd,
8f1b971b LL	226	unsigned long max_util, unsigned long sum_util,
8f1b971b LL	227	unsigned long allowed_cpu_cap)
27871f7a	228	{
aa11a7eb	229	struct em_perf_table *em_table;
521b512b	230	struct em_perf_state *ps;
1b600da5	231	int i;
27871f7a	232
aa11a7eb LL	233	#ifdef CONFIG_SCHED_DEBUG
	234	WARN_ONCE(!rcu_read_lock_held(), "EM: rcu read lock needed\n");
	235	#endif
	236
10803995 PK	237	if (!sum_util)
	238	return 0;
	239
27871f7a	240	/*
521b512b LL	241	* In order to predict the performance state, map the utilization of
521b512b LL	242	* the most utilized CPU of the performance domain to a requested
5a367f7b LL	243	* performance, like schedutil. Take also into account that the real
5a367f7b LL	244	* performance might be set lower (due to thermal capping). Thus, clamp
8f1b971b	245	* max utilization to the allowed CPU capacity before calculating
5a367f7b	246	* effective performance.
27871f7a	247	*/
1b600da5	248	max_util = map_util_perf(max_util);
8f1b971b	249	max_util = min(max_util, allowed_cpu_cap);
27871f7a QP	250
27871f7a QP	251	/*
521b512b	252	* Find the lowest performance state of the Energy Model above the
5a367f7b	253	* requested performance.
27871f7a	254	*/
aa11a7eb LL	255	em_table = rcu_dereference(pd->em_table);
aa11a7eb LL	256	i = em_pd_get_efficient_state(em_table->state, pd->nr_perf_states,
5a367f7b	257	max_util, pd->flags);
aa11a7eb	258	ps = &em_table->state[i];
27871f7a QP	259
27871f7a QP	260	/*
1b600da5 LL	261	* The performance (capacity) of a CPU in the domain at the performance
1b600da5 LL	262	* state (ps) can be computed as:
27871f7a	263	*
1b600da5 LL	264	* ps->freq * scale_cpu
	265	* ps->performance = -------------------- (1)
	266	* cpu_max_freq
27871f7a QP	267	*
27871f7a QP	268	* So, ignoring the costs of idle states (which are not available in
521b512b LL	269	* the EM), the energy consumed by this CPU at that performance state
521b512b LL	270	* is estimated as:
27871f7a	271	*
521b512b	272	* ps->power * cpu_util
27871f7a	273	* cpu_nrg = -------------------- (2)
1b600da5	274	* ps->performance
27871f7a	275	*
1b600da5 LL	276	* since 'cpu_util / ps->performance' represents its percentage of busy
1b600da5 LL	277	* time.
27871f7a QP	278	*
	279	* NOTE: Although the result of this computation actually is in
	280	* units of power, it can be manipulated as an energy value
	281	* over a scheduling period, since it is assumed to be
	282	* constant during that interval.
	283	*
	284	* By injecting (1) in (2), 'cpu_nrg' can be re-expressed as a product
	285	* of two terms:
	286	*
1b600da5 LL	287	* ps->power * cpu_max_freq
	288	* cpu_nrg = ------------------------ * cpu_util (3)
	289	* ps->freq * scale_cpu
27871f7a	290	*
521b512b LL	291	* The first term is static, and is stored in the em_perf_state struct
521b512b LL	292	* as 'ps->cost'.
27871f7a QP	293	*
27871f7a QP	294	* Since all CPUs of the domain have the same micro-architecture, they
521b512b	295	* share the same 'ps->cost', and the same CPU capacity. Hence, the
27871f7a QP	296	* total energy of the domain (which is the simple sum of the energy of
	297	* all of its CPUs) can be factorized as:
	298	*
1b600da5	299	* pd_nrg = ps->cost * \Sum cpu_util (4)
27871f7a	300	*/
1b600da5	301	return ps->cost * sum_util;
27871f7a QP	302	}
	303
	304	/**
521b512b LL	305	* em_pd_nr_perf_states() - Get the number of performance states of a perf.
521b512b LL	306	* domain
27871f7a QP	307	* @pd : performance domain for which this must be done
27871f7a QP	308	*
521b512b	309	* Return: the number of performance states in the performance domain table
27871f7a	310	*/
521b512b	311	static inline int em_pd_nr_perf_states(struct em_perf_domain *pd)
27871f7a	312	{
521b512b	313	return pd->nr_perf_states;
27871f7a QP	314	}
27871f7a QP	315
ee1a1987 LL	316	/**
	317	* em_perf_state_from_pd() - Get the performance states table of perf.
	318	* domain
	319	* @pd : performance domain for which this must be done
	320	*
	321	* To use this function the rcu_read_lock() should be hold. After the usage
	322	* of the performance states table is finished, the rcu_read_unlock() should
	323	* be called.
	324	*
	325	* Return: the pointer to performance states table of the performance domain
	326	*/
	327	static inline
	328	struct em_perf_state em_perf_state_from_pd(struct em_perf_domain pd)
	329	{
	330	return rcu_dereference(pd->em_table)->state;
	331	}
	332
27871f7a	333	#else
27871f7a	334	struct em_data_callback {};
bdc21a4d	335	#define EM_ADV_DATA_CB(_active_power_cb, _cost_cb) { }
27871f7a	336	#define EM_DATA_CB(_active_power_cb) { }
caeea9e6	337	#define EM_SET_ACTIVE_POWER_CB(em_cb, cb) do { } while (0)
27871f7a	338
7d9895c7 LL	339	static inline
7d9895c7 LL	340	int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
c250d50f	341	struct em_data_callback cb, cpumask_t span,
ae6ccaa6	342	bool microwatts)
7d9895c7 LL	343	{
	344	return -EINVAL;
	345	}
1bc138c6 LL	346	static inline void em_dev_unregister_perf_domain(struct device *dev)
	347	{
	348	}
27871f7a QP	349	static inline struct em_perf_domain *em_cpu_get(int cpu)
	350	{
	351	return NULL;
	352	}
1bc138c6 LL	353	static inline struct em_perf_domain em_pd_get(struct device dev)
	354	{
	355	return NULL;
	356	}
f0b56947	357	static inline unsigned long em_cpu_energy(struct em_perf_domain *pd,
8f1b971b LL	358	unsigned long max_util, unsigned long sum_util,
8f1b971b LL	359	unsigned long allowed_cpu_cap)
27871f7a QP	360	{
	361	return 0;
	362	}
521b512b	363	static inline int em_pd_nr_perf_states(struct em_perf_domain *pd)
27871f7a QP	364	{
	365	return 0;
	366	}
ffcf9bce LL	367	static inline
	368	struct em_perf_table __rcu em_table_alloc(struct em_perf_domain pd)
	369	{
	370	return NULL;
	371	}
	372	static inline void em_table_free(struct em_perf_table __rcu *table) {}
977230d5 LL	373	static inline
	374	int em_dev_update_perf_domain(struct device *dev,
	375	struct em_perf_table __rcu *new_table)
	376	{
	377	return -EINVAL;
	378	}
ee1a1987 LL	379	static inline
	380	struct em_perf_state em_perf_state_from_pd(struct em_perf_domain pd)
	381	{
	382	return NULL;
	383	}
22ea0284 LL	384	static inline
	385	int em_dev_compute_costs(struct device dev, struct em_perf_state table,
	386	int nr_states)
	387	{
	388	return -EINVAL;
	389	}
27871f7a QP	390	#endif
	391
	392	#endif