1 /* SPDX-License-Identifier: GPL-2.0 */
14  * struct em_perf_state - Performance state of a performance domain
16  * @power:	The power consumed at this level (by 1 CPU or by a registered
17  *		device). It can be a total power: static and dynamic.
19  *		energy calculation. Equal to: power * max_frequency / frequency
24 	unsigned long power;  member
34  * but a lower or equal power cost. Such inefficient states are ignored when
40  * struct em_perf_domain - Performance domain
44  * @cpus:		Cpumask covering the CPUs of the domain. It's here
49  * In case of CPU device, a "performance domain" represents a group of CPUs
50  * whose performance is scaled together. All CPUs of a performance domain
51  * must have the same micro-architecture. Performance domains often have
52  * a 1-to-1 mapping with CPUFreq policies. In case of other devices the @cpus
65  *  EM_PERF_DOMAIN_MICROWATTS: The power values are in micro-Watts or some
71  *  EM_PERF_DOMAIN_ARTIFICIAL: The power values are artificial and might be
72  *  created by platform missing real power information
78 #define em_span_cpus(em) (to_cpumask((em)->cpus))
79 #define em_is_artificial(em) ((em)->flags & EM_PERF_DOMAIN_ARTIFICIAL)
83  * The max power value in micro-Watts. The limit of 64 Watts is set as
85  * 32bit value limit for total Perf Domain power implies a limit of
86  * maximum CPUs in such domain to 64.
92  * limits to number of CPUs in the Perf. Domain.
106  * e.g. power ~1.3 Watt at max freq, so the 'cost' value > 1mln micro-Watts.
107  * In such scenario, where there are 4 CPUs in the Perf. Domain the 'sum_util'
124 	 * active_power() - Provide power at the next performance state of
127 	 * @power	: Active power at the performance state
133 	 * 'freq' and update 'power' and 'freq' to the matching active power
136 	 * In case of CPUs, the power is the one of a single CPU in the domain,
137 	 * expressed in micro-Watts or an abstract scale. It is expected to
142 	int (*active_power)(struct device *dev, unsigned long *power,
146 	 * get_cost() - Provide the cost at the given performance state of
153 	 * In case of CPUs, the cost is the one of a single CPU in the domain.
177  * em_pd_get_efficient_state() - Get an efficient performance state from the EM
178  * @pd   : Performance domain for which we want an efficient frequency
194 	for (i = 0; i < pd->nr_perf_states; i++) {  in em_pd_get_efficient_state()
195 		ps = &pd->table[i];  in em_pd_get_efficient_state()
196 		if (ps->frequency >= freq) {  in em_pd_get_efficient_state()
197 			if (pd->flags & EM_PERF_DOMAIN_SKIP_INEFFICIENCIES &&  in em_pd_get_efficient_state()
198 			    ps->flags & EM_PERF_STATE_INEFFICIENT)  in em_pd_get_efficient_state()
208  * em_cpu_energy() - Estimates the energy consumed by the CPUs of a
209  *		performance domain
210  * @pd		: performance domain for which energy has to be estimated
211  * @max_util	: highest utilization among CPUs of the domain
212  * @sum_util	: sum of the utilization of all CPUs in the domain
220  * Return: the sum of the energy consumed by the CPUs of the domain assuming
221  * a capacity state satisfying the max utilization of the domain.
236 	 * the most utilized CPU of the performance domain to a requested  in em_cpu_energy()
242 	cpu = cpumask_first(to_cpumask(pd->cpus));  in em_cpu_energy()
244 	ps = &pd->table[pd->nr_perf_states - 1];  in em_cpu_energy()
248 	freq = map_util_freq(max_util, ps->frequency, scale_cpu);  in em_cpu_energy()
257 	 * The capacity of a CPU in the domain at the performance state (ps)  in em_cpu_energy()
260 	 *             ps->freq * scale_cpu  in em_cpu_energy()
261 	 *   ps->cap = --------------------                          (1)  in em_cpu_energy()
268 	 *             ps->power * cpu_util  in em_cpu_energy()
269 	 *   cpu_nrg = --------------------                          (2)  in em_cpu_energy()
270 	 *                   ps->cap  in em_cpu_energy()
272 	 * since 'cpu_util / ps->cap' represents its percentage of busy time.  in em_cpu_energy()
275 	 *         units of power, it can be manipulated as an energy value  in em_cpu_energy()
279 	 * By injecting (1) in (2), 'cpu_nrg' can be re-expressed as a product  in em_cpu_energy()
282 	 *             ps->power * cpu_max_freq   cpu_util  in em_cpu_energy()
283 	 *   cpu_nrg = ------------------------ * ---------          (3)  in em_cpu_energy()
284 	 *                    ps->freq            scale_cpu  in em_cpu_energy()
287 	 * as 'ps->cost'.  in em_cpu_energy()
289 	 * Since all CPUs of the domain have the same micro-architecture, they  in em_cpu_energy()
290 	 * share the same 'ps->cost', and the same CPU capacity. Hence, the  in em_cpu_energy()
291 	 * total energy of the domain (which is the simple sum of the energy of  in em_cpu_energy()
294 	 *            ps->cost * \Sum cpu_util  in em_cpu_energy()
295 	 *   pd_nrg = ------------------------                       (4)  in em_cpu_energy()
298 	return em_estimate_energy(ps->cost, sum_util, scale_cpu);  in em_cpu_energy()
302  * em_pd_nr_perf_states() - Get the number of performance states of a perf.
303  *				domain
304  * @pd		: performance domain for which this must be done
306  * Return: the number of performance states in the performance domain table
310 	return pd->nr_perf_states;  in em_pd_nr_perf_states()
324 	return -EINVAL;  in em_dev_register_perf_domain()