Messages in this thread | | | From | "Yuan, Perry" <> | Subject | RE: [PATCH v9 02/13] Documentation: amd-pstate: add EPP profiles introduction | Date | Thu, 5 Jan 2023 03:18:23 +0000 |
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[AMD Official Use Only - General]
Hi Mario.
> -----Original Message----- > From: Limonciello, Mario <Mario.Limonciello@amd.com> > Sent: Wednesday, January 4, 2023 8:29 AM > To: Yuan, Perry <Perry.Yuan@amd.com>; rafael.j.wysocki@intel.com; Huang, > Ray <Ray.Huang@amd.com>; viresh.kumar@linaro.org > Cc: Sharma, Deepak <Deepak.Sharma@amd.com>; Fontenot, Nathan > <Nathan.Fontenot@amd.com>; Deucher, Alexander > <Alexander.Deucher@amd.com>; Huang, Shimmer > <Shimmer.Huang@amd.com>; Du, Xiaojian <Xiaojian.Du@amd.com>; Meng, > Li (Jassmine) <Li.Meng@amd.com>; Karny, Wyes <Wyes.Karny@amd.com>; > linux-pm@vger.kernel.org; linux-kernel@vger.kernel.org > Subject: Re: [PATCH v9 02/13] Documentation: amd-pstate: add EPP profiles > introduction > > On 12/25/2022 10:34, Perry Yuan wrote: > > From: Perry Yuan <Perry.Yuan@amd.com> > > > > The amd-pstate driver supports a feature called energy performance > > preference (EPP). Add information to the documentation to explain how > > users can interact with the sysfs files for this feature. > > > > 1) See all EPP profiles > > $ sudo cat > > > /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_available_pr > ef > > erences default performance balance_performance balance_power power > > > > 2) Check current EPP profile > > $ sudo cat > > /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference > > performance > > > > 3) Set new EPP profile > > $ sudo bash -c "echo power > > /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference" > > > > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com> > > Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> >
I just got back from sick leave, will pick all your R-B flags and send v10 out. Thank you help to review this version.
Perry.
> > --- > > Documentation/admin-guide/pm/amd-pstate.rst | 19 > +++++++++++++++++++ > > 1 file changed, 19 insertions(+) > > > > diff --git a/Documentation/admin-guide/pm/amd-pstate.rst > > b/Documentation/admin-guide/pm/amd-pstate.rst > > index 06e23538f79c..33ab8ec8fc2f 100644 > > --- a/Documentation/admin-guide/pm/amd-pstate.rst > > +++ b/Documentation/admin-guide/pm/amd-pstate.rst > > @@ -262,6 +262,25 @@ lowest non-linear performance in `AMD CPPC > Performance Capability > > <perf_cap_>`_.) > > This attribute is read-only. > > > > +``energy_performance_available_preferences`` > > + > > +A list of all the supported EPP preferences that could be used for > > +``energy_performance_preference`` on this system. > > +These profiles represent different hints that are provided to the > > +low-level firmware about the user's desired energy vs efficiency > > +tradeoff. ``default`` represents the epp value is set by platform > > +firmware. This attribute is read-only. > > + > > +``energy_performance_preference`` > > + > > +The current energy performance preference can be read from this > attribute. > > +and user can change current preference according to energy or > > +performance needs Please get all support profiles list from > > +``energy_performance_available_preferences`` attribute, all the > > +profiles are integer values defined between 0 to 255 when EPP feature > > +is enabled by platform firmware, if EPP feature is disabled, driver > > +will ignore the written value This attribute is read-write. > > + > > Other performance and frequency values can be read back from > > ``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`. > >
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