From: Vincent Guittot vincent.guittot@linaro.org
The last item of a performance domain is not always the performance point that has been used to compute CPU's capacity. This can lead to different target frequency compared with other part of the system like schedutil and would result in wrong energy estimation.
A new arch_scale_freq_ref() is available to return a fixed and coherent frequency reference that can be used when computing the CPU's frequency for an level of utilization. Use this function to get this reference frequency.
Energy model is never used without defining arch_scale_freq_ref() but can be compiled. Define a default arch_scale_freq_ref() returning 0 in such case.
Signed-off-by: Vincent Guittot vincent.guittot@linaro.org Signed-off-by: Ingo Molnar mingo@kernel.org Tested-by: Lukasz Luba lukasz.luba@arm.com Reviewed-by: Lukasz Luba lukasz.luba@arm.com Link: https://lore.kernel.org/r/20231211104855.558096-5-vincent.guittot@linaro.org (cherry picked from commit 15cbbd1d317e07b4e5c6aca5d4c5579539a82784) Stable-dep-of: e37617c8e53a ("sched/fair: Fix frequency selection for non-invariant case") Signed-off-by: Wentao Guan guanwentao@uniontech.com --- include/linux/energy_model.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h index adec808b371a..88d91e087471 100644 --- a/include/linux/energy_model.h +++ b/include/linux/energy_model.h @@ -224,7 +224,7 @@ 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) { - unsigned long freq, scale_cpu; + unsigned long freq, ref_freq, scale_cpu; struct em_perf_state *ps; int cpu;
@@ -241,10 +241,10 @@ 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(cpu);
max_util = min(max_util, allowed_cpu_cap); - freq = map_util_freq(max_util, ps->frequency, scale_cpu); + freq = map_util_freq(max_util, ref_freq, scale_cpu);
/* * Find the lowest performance state of the Energy Model above the