Messages in this thread | | | From | "Yuan, Perry" <> | Subject | RE: [PATCH v3 2/8] Documentation: amd-pstate: add EPP profiles introduction | Date | Sun, 13 Nov 2022 16:23:37 +0000 |
| |
[AMD Official Use Only - General]
Hi Mario
> -----Original Message----- > From: Limonciello, Mario <Mario.Limonciello@amd.com> > Sent: Tuesday, November 8, 2022 2:34 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>; linux-pm@vger.kernel.org; linux- > kernel@vger.kernel.org > Subject: Re: [PATCH v3 2/8] Documentation: amd-pstate: add EPP profiles > introduction > > On 11/7/2022 11:56, Perry Yuan wrote: > > The patch add AMD pstate EPP feature introduction and what EPP > > preference supported for AMD processors. > > > > User can get supported list from > > energy_performance_available_preferences attribute file, or update > > current profile to energy_performance_preference file > > > > 1) See all EPP profiles > > $ sudo cat > > > /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_available_pref > > 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> > > --- > > 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 8f3d30c5a0d8..78c6525d5a49 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`` > > + > > +All the supported EPP preference could be selected, List of the > > +strings that can be set to the ``energy_performance_preference`` > > +attribute those different profiles represent different energy vs > > +efficiency hints provided to low-level firmware however, the > > +``default`` represents the epp value is set by platform firmware This > > +attribute is read-only. > > My proposal at rewording it. > > 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.
Make sense. Fixed in V4 as you suggested.
> > > > + > > +``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`. > >
| |