linux-kernel - [PATCH 4/7 v2] energy model: Remove unused em_cpu

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Message-ID: <20241217160720.2397239-5-vincent.guittot@linaro.org>
Date: Tue, 17 Dec 2024 17:07:17 +0100
From: Vincent Guittot <vincent.guittot@...aro.org>
To: mingo@...hat.com,
	peterz@...radead.org,
	juri.lelli@...hat.com,
	dietmar.eggemann@....com,
	rostedt@...dmis.org,
	bsegall@...gle.com,
	mgorman@...e.de,
	vschneid@...hat.com,
	lukasz.luba@....com,
	rafael.j.wysocki@...el.com,
	linux-kernel@...r.kernel.org
Cc: qyousef@...alina.io,
	hongyan.xia2@....com,
	pierre.gondois@....com,
	christian.loehle@....com,
	qperret@...gle.com,
	Vincent Guittot <vincent.guittot@...aro.org>
Subject: [PATCH 4/7 v2] energy model: Remove unused em_cpu_energy()

Remove the unused function em_cpu_energy()

Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
---
 include/linux/energy_model.h | 99 ------------------------------------
 1 file changed, 99 deletions(-)

diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
index 26d0ff72feac..c766642dc541 100644
--- a/include/linux/energy_model.h
+++ b/include/linux/energy_model.h
@@ -235,99 +235,6 @@ em_pd_get_previous_state(struct em_perf_state *table,
 	return -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 = 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, max_util);
-	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
@@ -394,12 +301,6 @@ em_pd_get_previous_state(struct em_perf_state *table, int nr_perf_states,
 {
 	return -1;
 }
-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;
-- 
2.43.0