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Message-ID: <ba1e8112-c82e-458d-b7f7-9a308295d260@arm.com>
Date: Mon, 29 Jan 2024 19:13:57 +0100
From: Dietmar Eggemann <dietmar.eggemann@....com>
To: Lukasz Luba <lukasz.luba@....com>, linux-kernel@...r.kernel.org,
linux-pm@...r.kernel.org, rafael@...nel.org
Cc: rui.zhang@...el.com, amit.kucheria@...durent.com, amit.kachhap@...il.com,
daniel.lezcano@...aro.org, viresh.kumar@...aro.org, len.brown@...el.com,
pavel@....cz, mhiramat@...nel.org, qyousef@...alina.io, wvw@...gle.com,
xuewen.yan94@...il.com
Subject: Re: [PATCH v7 13/23] PM: EM: Add performance field to struct
em_perf_state and optimize
On 17/01/2024 09:57, Lukasz Luba wrote:
[...]
> include/linux/energy_model.h | 24 ++++++++++++------------
> kernel/power/energy_model.c | 27 +++++++++++++++++++++++++++
> 2 files changed, 39 insertions(+), 12 deletions(-)
>
> diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
> index 5ebe9dbec8e1..689d71f6b56f 100644
> --- a/include/linux/energy_model.h
> +++ b/include/linux/energy_model.h
> @@ -13,6 +13,7 @@
>
> /**
> * struct em_perf_state - Performance state of a performance domain
> + * @performance: CPU performance (capacity) at a given frequency
I guess this is what we called the 'current CPU capacity' in older
Android versions.
[...]
> @@ -260,26 +262,24 @@ static inline unsigned long em_cpu_energy(struct em_perf_domain *pd,
> /*
> * In order to predict the performance state, map the utilization of
> * the most utilized CPU of the performance domain to a requested
> - * frequency, like schedutil. Take also into account that the real
> - * frequency might be set lower (due to thermal capping). Thus, clamp
> + * performance, like schedutil. Take also into account that the real
> + * performance might be set lower (due to thermal capping). Thus, clamp
> * max utilization to the allowed CPU capacity before calculating
> - * effective frequency.
> + * effective performance.
> */
> cpu = cpumask_first(to_cpumask(pd->cpus));
> scale_cpu = arch_scale_cpu_capacity(cpu);
> - ref_freq = arch_scale_freq_ref(cpu);
>
> max_util = map_util_perf(max_util);
Didn't apply cleanly on tip sched/code for me.
Looks like it's missing:
9c0b4bb7f630 - sched/cpufreq: Rework schedutil governor performance
estimation (2023-11-23 Vincent Guittot)
> max_util = min(max_util, allowed_cpu_cap);
> - freq = map_util_freq(max_util, ref_freq, scale_cpu);
Since you're removing this here, shouldn't you also remove
* In order to predict the performance state, map the utilization of
* the most utilized CPU of the performance domain to a requested
Looks like with 9c0b4bb7f630 there is no mapping anymore?
[...]
> static int em_compute_costs(struct device *dev, struct em_perf_state *table,
> struct em_data_callback *cb, int nr_states,
> unsigned long flags)
> @@ -318,6 +343,8 @@ static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd,
> table[i].frequency = prev_freq = freq;
> }
>
> + em_init_performance(dev, pd, table, nr_states);
Looks like pd already has 'pd->nr_perf_states' initialized. so just
passing pd seems to be sufficient. Like for em_table_alloc() and
em_create_perf_table().
[...]
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