linux-kernel - Re: [PATCH v3 12/21] cpufreq: amd: add amd-pstate performance attributes

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Message-ID: <d0418254-37c2-347c-52e5-a9de72bc08d5@amd.com>
Date:   Fri, 5 Nov 2021 13:50:49 -0500
From:   Nathan Fontenot <nafonten@....com>
To:     Huang Rui <ray.huang@....com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Shuah Khan <skhan@...uxfoundation.org>,
        Borislav Petkov <bp@...e.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Giovanni Gherdovich <ggherdovich@...e.cz>,
        linux-pm@...r.kernel.org
Cc:     Deepak Sharma <deepak.sharma@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Mario Limonciello <mario.limonciello@....com>,
        Steven Noonan <steven@...vesoftware.com>,
        Nathan Fontenot <nathan.fontenot@....com>,
        Jinzhou Su <Jinzhou.Su@....com>,
        Xiaojian Du <Xiaojian.Du@....com>,
        linux-kernel@...r.kernel.org, x86@...nel.org
Subject: Re: [PATCH v3 12/21] cpufreq: amd: add amd-pstate performance
 attributes

On 10/29/21 8:02 AM, Huang Rui wrote:
> Introduce sysfs attributes to get the different level amd-pstate
> performances.

Can you explain why we need to provide duplicate sysfs entries for
these values?

Each one of these are already created by the drivers/acpi code and exist
in sysfs (see /sys/devices/system/cpu/cpuX/acpi_cppc).

-Nathan

> 
> Signed-off-by: Huang Rui <ray.huang@....com>
> ---
>  drivers/cpufreq/amd-pstate.c | 53 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 8cf1e80f44e0..58ee50bf492b 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -536,14 +536,67 @@ static ssize_t show_amd_pstate_lowest_nonlinear_freq(struct cpufreq_policy *poli
>  	return sprintf(&buf[0], "%u\n", freq);
>  }
>  
> +static ssize_t show_amd_pstate_highest_perf(struct cpufreq_policy *policy,
> +					    char *buf)
> +{
> +	u32 perf;
> +	struct amd_cpudata *cpudata = policy->driver_data;
> +
> +	perf = READ_ONCE(cpudata->highest_perf);
> +
> +	return sprintf(&buf[0], "%u\n", perf);
> +}
> +
> +static ssize_t show_amd_pstate_nominal_perf(struct cpufreq_policy *policy,
> +					    char *buf)
> +{
> +	u32 perf;
> +	struct amd_cpudata *cpudata = policy->driver_data;
> +
> +	perf = READ_ONCE(cpudata->nominal_perf);
> +
> +	return sprintf(&buf[0], "%u\n", perf);
> +}
> +
> +static ssize_t show_amd_pstate_lowest_nonlinear_perf(struct cpufreq_policy *policy,
> +						     char *buf)
> +{
> +	u32 perf;
> +	struct amd_cpudata *cpudata = policy->driver_data;
> +
> +	perf = READ_ONCE(cpudata->lowest_nonlinear_perf);
> +
> +	return sprintf(&buf[0], "%u\n", perf);
> +}
> +
> +static ssize_t show_amd_pstate_lowest_perf(struct cpufreq_policy *policy,
> +					   char *buf)
> +{
> +	u32 perf;
> +	struct amd_cpudata *cpudata = policy->driver_data;
> +
> +	perf = READ_ONCE(cpudata->lowest_perf);
> +
> +	return sprintf(&buf[0], "%u\n", perf);
> +}
> +
>  cpufreq_freq_attr_ro(amd_pstate_max_freq);
>  cpufreq_freq_attr_ro(amd_pstate_nominal_freq);
>  cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
>  
> +cpufreq_freq_attr_ro(amd_pstate_highest_perf);
> +cpufreq_freq_attr_ro(amd_pstate_nominal_perf);
> +cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_perf);
> +cpufreq_freq_attr_ro(amd_pstate_lowest_perf);
> +
>  static struct freq_attr *amd_pstate_attr[] = {
>  	&amd_pstate_max_freq,
>  	&amd_pstate_nominal_freq,
>  	&amd_pstate_lowest_nonlinear_freq,
> +	&amd_pstate_highest_perf,
> +	&amd_pstate_nominal_perf,
> +	&amd_pstate_lowest_nonlinear_perf,
> +	&amd_pstate_lowest_perf,
>  	NULL,
>  };
>  
>