[PATCH 2/7 v6] energy model: Add a get previous state function

From: Vincent Guittot
Date: Fri Mar 14 2025 - 12:36:41 EST


Instead of parsing the entire EM table everytime, add a function to get the
previous state.

Will be used in the scheduler feec() function.

Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
---
include/linux/energy_model.h | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)

diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
index 78318d49276d..551e243b9c43 100644
--- a/include/linux/energy_model.h
+++ b/include/linux/energy_model.h
@@ -216,6 +216,26 @@ em_pd_get_efficient_state(struct em_perf_state *table,
return max_ps;
}

+static inline int
+em_pd_get_previous_state(struct em_perf_state *table,
+ struct em_perf_domain *pd, int idx)
+{
+ unsigned long pd_flags = pd->flags;
+ int min_ps = pd->min_perf_state;
+ struct em_perf_state *ps;
+ int i;
+
+ for (i = idx - 1; i >= min_ps; i--) {
+ ps = &table[i];
+ if (pd_flags & EM_PERF_DOMAIN_SKIP_INEFFICIENCIES &&
+ ps->flags & EM_PERF_STATE_INEFFICIENT)
+ continue;
+ return i;
+ }
+
+ return -1;
+}
+
/**
* em_cpu_energy() - Estimates the energy consumed by the CPUs of a
* performance domain
@@ -362,6 +382,18 @@ static inline struct em_perf_domain *em_pd_get(struct device *dev)
{
return NULL;
}
+static inline int
+em_pd_get_efficient_state(struct em_perf_state *table,
+ struct em_perf_domain *pd, unsigned long max_util)
+{
+ return 0;
+}
+static inline int
+em_pd_get_previous_state(struct em_perf_state *table,
+ struct em_perf_domain *pd, int idx)
+{
+ 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)
--
2.43.0