linux-kernel - Re: [PATCH 15/19] cpupower: add amd-pstate sysfs entries into libcpufreq

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Date:   Thu, 16 Sep 2021 16:47:04 +0800
From:   Huang Rui <ray.huang@....com>
To:     Shuah Khan <skhan@...uxfoundation.org>
CC:     "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Borislav Petkov <bp@...e.de>, Ingo Molnar <mingo@...nel.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "Sharma, Deepak" <Deepak.Sharma@....com>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        "Limonciello, Mario" <Mario.Limonciello@....com>,
        "Fontenot, Nathan" <Nathan.Fontenot@....com>,
        "Su, Jinzhou (Joe)" <Jinzhou.Su@....com>,
        "Du, Xiaojian" <Xiaojian.Du@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>
Subject: Re: [PATCH 15/19] cpupower: add amd-pstate sysfs entries into
 libcpufreq

On Fri, Sep 10, 2021 at 06:26:06AM +0800, Shuah Khan wrote:
> On 9/8/21 8:59 AM, Huang Rui wrote:
> > These amd-pstate sysfs entries will be used on cpupower 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@....com>
> > ---
> >   tools/power/cpupower/lib/cpufreq.c | 18 +++++++++++++++++-
> >   1 file changed, 17 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tools/power/cpupower/lib/cpufreq.c b/tools/power/cpupower/lib/cpufreq.c
> > index c3b56db8b921..3f92ddadaad2 100644
> > --- a/tools/power/cpupower/lib/cpufreq.c
> > +++ b/tools/power/cpupower/lib/cpufreq.c
> > @@ -69,6 +69,14 @@ enum cpufreq_value {
> >   	SCALING_MIN_FREQ,
> >   	SCALING_MAX_FREQ,
> >   	STATS_NUM_TRANSITIONS,
> > +	AMD_PSTATE_HIGHEST_PERF,
> > +	AMD_PSTATE_NOMINAL_PERF,
> > +	AMD_PSTATE_LOWEST_NONLINEAR_PERF,
> > +	AMD_PSTATE_LOWEST_PERF,
> > +	AMD_PSTATE_MAX_FREQ,
> > +	AMD_PSTATE_NOMINAL_FREQ,
> > +	AMD_PSTATE_LOWEST_NONLINEAR_FREQ,
> > +	AMD_PSTATE_MIN_FREQ,
> >   	MAX_CPUFREQ_VALUE_READ_FILES
> >   };
> >   
> 
> These are AMD specific values being added to a common code.
> 
> > @@ -80,7 +88,15 @@ static const char *cpufreq_value_files[MAX_CPUFREQ_VALUE_READ_FILES] = {
> >   	[SCALING_CUR_FREQ] = "scaling_cur_freq",
> >   	[SCALING_MIN_FREQ] = "scaling_min_freq",
> >   	[SCALING_MAX_FREQ] = "scaling_max_freq",
> > -	[STATS_NUM_TRANSITIONS] = "stats/total_trans"
> > +	[STATS_NUM_TRANSITIONS] = "stats/total_trans",
> > +	[AMD_PSTATE_HIGHEST_PERF] = "amd_pstate_highest_perf",
> > +	[AMD_PSTATE_NOMINAL_PERF] = "amd_pstate_nominal_perf",
> > +	[AMD_PSTATE_LOWEST_NONLINEAR_PERF] = "amd_pstate_lowest_nonlinear_perf",
> > +	[AMD_PSTATE_LOWEST_PERF] = "amd_pstate_lowest_perf",
> > +	[AMD_PSTATE_MAX_FREQ] = "amd_pstate_max_freq",
> > +	[AMD_PSTATE_NOMINAL_FREQ] = "amd_pstate_nominal_freq",
> > +	[AMD_PSTATE_LOWEST_NONLINEAR_FREQ] = "amd_pstate_lowest_nonlinear_freq",
> > +	[AMD_PSTATE_MIN_FREQ] = "amd_pstate_min_freq"
> >   };
> >   
> >   
> > 
> 
> These are AMD specific values being added to a common code.
> It doesn't sound right. What happens if there is a conflict
> between AMD values and another vendor values?
> 
> This doesn't seem a good place to add these.
> 

Shuah, thanks for your suggestion, I went through the cpupower patches
again. And yes, we should not combine the amd specific and common things
together.

Could I expose a simliar sysfs_cpufreq_get_one_value in cpupower_intern.h
header, and move amd_pstate_* function implementation into
utils/helpers/amd.c? It can keep the lib/cpufreq still general.

Thanks,
Ray