| Message ID | 20231009103621.374412-6-vincent.guittot@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | consolidate and cleanup CPU capacity | expand |
Hi Vincent, On 10/9/23 11:36, Vincent Guittot wrote: > 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> > --- > include/linux/energy_model.h | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > LGTM, taking into account the patch 2/6 that we don't include any boost freq (so no changes w.r.t. current EAS situation) Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h index b9caa01dfac4..1b0c8490d4bd 100644 --- a/include/linux/energy_model.h +++ b/include/linux/energy_model.h @@ -204,6 +204,14 @@ struct em_perf_state *em_pd_get_efficient_state(struct em_perf_domain *pd, return ps; } +#ifndef arch_scale_freq_ref +static __always_inline +unsigned int arch_scale_freq_ref(int cpu) +{ + return 0; +} +#endif + /** * em_cpu_energy() - Estimates the energy consumed by the CPUs of a * performance domain @@ -224,7 +232,7 @@ 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; @@ -241,11 +249,11 @@ 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(cpu); max_util = map_util_perf(max_util); 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
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> --- include/linux/energy_model.h | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)