Re: [PATCH 16/19] cpupower: enable boost state support for amd-pstate module

From: Shuah Khan <skhan@linuxfoundation.org>
To: Huang Rui <ray.huang@amd.com>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Borislav Petkov <bp@suse.de>, Ingo Molnar <mingo@kernel.org>,
	linux-pm@vger.kernel.org
Cc: Deepak Sharma <deepak.sharma@amd.com>,
	Alex Deucher <alexander.deucher@amd.com>,
	Mario Limonciello <mario.limonciello@amd.com>,
	Nathan Fontenot <nathan.fontenot@amd.com>,
	Jinzhou Su <Jinzhou.Su@amd.com>,
	Xiaojian Du <Xiaojian.Du@amd.com>,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	Shuah Khan <skhan@linuxfoundation.org>
Subject: Re: [PATCH 16/19] cpupower: enable boost state support for amd-pstate module
Date: Thu, 9 Sep 2021 16:42:42 -0600	[thread overview]
Message-ID: <ed2906aa-d898-9d3a-ed04-7ad0ecc51f96@linuxfoundation.org> (raw)
In-Reply-To: <20210908150001.3702552-17-ray.huang@amd.com>

On 9/8/21 8:59 AM, Huang Rui wrote:
> The AMD P-state boost API is different from ACPI hardware P-states, so
> implement the support for amd-pstate kernel module.
> 

This commit log doesn't make sense. If these sysfs entries are used
for amd-pstate kernel module, why are they defined here.

Describe how these are used and the relationship between these defines
and the amd-pstate kernel module

> Signed-off-by: Huang Rui <ray.huang@amd.com>
> ---
>   tools/power/cpupower/lib/cpufreq.c        | 20 ++++++++++++++++++++
>   tools/power/cpupower/lib/cpufreq.h        |  3 +++
>   tools/power/cpupower/utils/helpers/misc.c |  7 +++++++
>   3 files changed, 30 insertions(+)
> 
> diff --git a/tools/power/cpupower/lib/cpufreq.c b/tools/power/cpupower/lib/cpufreq.c
> index 3f92ddadaad2..37da87bdcfb1 100644
> --- a/tools/power/cpupower/lib/cpufreq.c
> +++ b/tools/power/cpupower/lib/cpufreq.c
> @@ -790,3 +790,23 @@ unsigned long cpufreq_get_transitions(unsigned int cpu)
>   {
>   	return sysfs_cpufreq_get_one_value(cpu, STATS_NUM_TRANSITIONS);
>   }
> +
> +int amd_pstate_boost_support(unsigned int cpu)
> +{
> +	unsigned int highest_perf, nominal_perf;
> +
> +	highest_perf = sysfs_cpufreq_get_one_value(cpu, AMD_PSTATE_HIGHEST_PERF);
> +	nominal_perf = sysfs_cpufreq_get_one_value(cpu, AMD_PSTATE_NOMINAL_PERF);
> +
> +	return highest_perf > nominal_perf ? 1 : 0;
> +}
> +
> +int amd_pstate_boost_enabled(unsigned int cpu)
> +{
> +	unsigned int cpuinfo_max, amd_pstate_max;
> +
> +	cpuinfo_max = sysfs_cpufreq_get_one_value(cpu, CPUINFO_MAX_FREQ);
> +	amd_pstate_max = sysfs_cpufreq_get_one_value(cpu, AMD_PSTATE_MAX_FREQ);
> +
> +	return cpuinfo_max == amd_pstate_max ? 1 : 0;
> +}

Why are these amd specific routines added to common file.
Why not add them to tools/power/cpupower/utils/helpers/amd.c?

> diff --git a/tools/power/cpupower/lib/cpufreq.h b/tools/power/cpupower/lib/cpufreq.h
> index 95f4fd9e2656..d54d02a7a4f4 100644
> --- a/tools/power/cpupower/lib/cpufreq.h
> +++ b/tools/power/cpupower/lib/cpufreq.h
> @@ -203,6 +203,9 @@ int cpufreq_modify_policy_governor(unsigned int cpu, char *governor);
>   int cpufreq_set_frequency(unsigned int cpu,
>   				unsigned long target_frequency);
>   
> +int amd_pstate_boost_support(unsigned int cpu);
> +int amd_pstate_boost_enabled(unsigned int cpu);
> +
>   #ifdef __cplusplus
>   }
>   #endif
> diff --git a/tools/power/cpupower/utils/helpers/misc.c b/tools/power/cpupower/utils/helpers/misc.c
> index 07d80775fb68..aba979320760 100644
> --- a/tools/power/cpupower/utils/helpers/misc.c
> +++ b/tools/power/cpupower/utils/helpers/misc.c
> @@ -10,6 +10,7 @@
>   #if defined(__i386__) || defined(__x86_64__)
>   
>   #include "cpupower_intern.h"
> +#include "cpufreq.h"
>   
>   #define MSR_AMD_HWCR	0xc0010015
>   
> @@ -39,6 +40,12 @@ int cpufreq_has_boost_support(unsigned int cpu, int *support, int *active,
>   	

This logic here calls amd_pci_get_num_boost_states() ---
There is another routine called decode_pstates() in
tools/power/cpupower/utils/helpers/amd.c

		if (ret)
>   				return ret;
>   		}
> +	} if ((cpupower_cpu_info.caps & CPUPOWER_CAP_AMD_PSTATE) &&
> +	      amd_pstate_boost_support(cpu)) {

Coupled with the above routines, the naming amd_pstate_boost_support()
is rather confusing.

Also why is this amd_pstate_boost_support() added to
> +		*support = 1;
> +
> +		if (amd_pstate_boost_enabled(cpu))
> +			*active = 1;
>   	} else if (cpupower_cpu_info.caps & CPUPOWER_CAP_INTEL_IDA)
>   		*support = *active = 1;
>   	return 0;
> 

thanks,
-- Shuah