Thread (29 messages) 29 messages, 7 authors, 2023-09-25

Re: [PATCH 4/4] energy_model: use a fixed reference frequency

From: Dietmar Eggemann <dietmar.eggemann@arm.com>
Date: 2023-09-14 21:07:31
Also in: linux-pm, linux-riscv, lkml

On 01/09/2023 15:03, Vincent Guittot wrote:

[...]
quoted hunk ↗ jump to hunk
diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
index b9caa01dfac4..7ee07be6928e 100644
--- a/include/linux/energy_model.h
+++ b/include/linux/energy_model.h
@@ -204,6 +204,20 @@ struct em_perf_state *em_pd_get_efficient_state(struct em_perf_domain *pd,
 	return ps;
 }
 
+#ifdef arch_scale_freq_ref
+static __always_inline
+unsigned long  arch_scale_freq_ref_em(int cpu, struct em_perf_domain *pd)
Why is this function named with the arch prefix?

So far we have 5 arch functions (arch_scale_freq_tick() <->
arch_scale_freq_ref()) and e.g. Arm/Arm64 defines them with there
topology_foo implementations.

Isn't arch_scale_freq_ref_em() (as well as arch_scale_freq_ref_policy())
different in this sense and so a proper EM function which should
manifest in its name?
+{
+	return arch_scale_freq_ref(cpu);
+}
+#else
+static __always_inline
+unsigned long  arch_scale_freq_ref_em(int cpu, struct em_perf_domain *pd)
+{
+	return pd->table[pd->nr_perf_states - 1].frequency;
+}
+#endif
[...]
quoted hunk ↗ jump to hunk
@@ -241,11 +255,11 @@ static inline unsigned long em_cpu_energy(struct em_perf_domain *pd,
 	 */
 	cpu = cpumask_first(to_cpumask(pd->cpus));
 	scale_cpu = arch_scale_cpu_capacity(cpu);
-	ps = &pd->table[pd->nr_perf_states - 1];
+	ref_freq = arch_scale_freq_ref_em(cpu, pd);
Why not using existing `unsigned long freq` here like in schedutil's
get_next_freq()?
 
 	max_util = map_util_perf(max_util);
[...]


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