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-arm-kernel, 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);
[...]