Messages in this thread | | | Date | Mon, 7 Nov 2022 12:33:50 -0600 | Subject | Re: [PATCH v3 2/8] Documentation: amd-pstate: add EPP profiles introduction | From | "Limonciello, Mario" <> |
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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_preferences > 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.
> + > +``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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