Messages in this thread | | | From | "Yuan, Perry" <> | Subject | RE: [PATCH v4 9/9] Documentation: amd-pstate: add amd pstate driver mode introduction | Date | Fri, 2 Dec 2022 08:20:31 +0000 |
| |
[AMD Official Use Only - General]
Hi Mario
> -----Original Message----- > From: Limonciello, Mario <Mario.Limonciello@amd.com> > Sent: Tuesday, November 15, 2022 6:29 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 v4 9/9] Documentation: amd-pstate: add amd pstate > driver mode introduction > > Please run this through a spell checker before v5. > > On 11/10/2022 11:58, Perry Yuan wrote: > > Introduce ``amd-pstate`` CPPC has two operation modes: > > * CPPC Autonomous (active) mode > > * CPPC non-autonomous (passive) mode. > > active mode and passive mode can be choosed by whith different kernel > parameters. > > can be chosen by different kernel parameters
Forget to reply this, I have fixed the words typo in the v6. Thanks for your review. Perry.
> > > > > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com> > > --- > > Documentation/admin-guide/pm/amd-pstate.rst | 47 > +++++++++++++++++++-- > > 1 file changed, 43 insertions(+), 4 deletions(-) > > > > diff --git a/Documentation/admin-guide/pm/amd-pstate.rst > > b/Documentation/admin-guide/pm/amd-pstate.rst > > index e7488891b12f..6ba02a658b31 100644 > > --- a/Documentation/admin-guide/pm/amd-pstate.rst > > +++ b/Documentation/admin-guide/pm/amd-pstate.rst > > @@ -302,11 +302,11 @@ efficiency frequency management method on > AMD processors. > > Kernel Module Options for ``amd-pstate`` > > ========================================= > > > > -.. _shared_mem: > > +.. legacy_cppc: > > > > -``shared_mem`` > > -Use a module param (shared_mem) to enable related processors > manually > > with -**amd_pstate.shared_mem=1**. > > +``legacy_cppc`` > > +Use a module param (legacy_cppc) to enable related processors > > +manually with **amd_pstate=legacy_cppc**. > > Due to the performance issue on the processors with `Shared Memory > Support > > <perf_cap_>`_, we disable it presently and will re-enable this by default > > once we address performance issue with this solution. > > @@ -321,6 +321,45 @@ If the CPU flags have ``cppc``, then this processor > supports `Full MSR Support > > <perf_cap_>`_. Otherwise, it supports `Shared Memory Support > <perf_cap_>`_. > > > > > > +AMD Pstae Driver Operation Modes > > Pstate > > > +================================= > > + > > +``amd-pstate`` CPPC has two operation modes: CPPC Autonomous(active) > > +mode and CPPC non-autonomous(passive) mode. > > +active mode and passive mode can be choosed by whith different kernel > parameters. > > can be chosen by different kernel parameters > > > +When in Autonomous mode, CPPC ignores requests done in the Desired > > +Performance Target register and takes into account only the values > > +set to the Minimum requested performance, Maximum requested > > +performance, and Energy Performance Preference registers. When > Autonomous is disabled, it only considers the Desired Performance Target. > > + > > +Active Mode > > +------------ > > + > > +``amd-pstate-epp`` > > + > > +This is the low-level firmware control mode which is implemented by > > +``amd-pstate-epp`` driver with ``amd-pstate=active`` passed to the kernel > in the command line. > > +In this mode, ``amd-pstate-epp`` driver provides a hint to the > > +hardware if software wants to bias toward performance (0x0) or energy > efficiency (0xff) to the CPPC firmware. > > +then CPPC power algorithm will calculate the runtime workload and > > +adjust the realtime cores frequency according to the power supply and > > +thermal, core voltage and some other hardware conditions. > > + > > +Passive Mode > > +------------ > > + > > +``amd-pstate`` > > + > > +It will be enabled if the ``amd_pstate=passive`` is passed to the kernel in > the command line. > > +In this mode, ``amd-pstate``driver software specifies a desired QoS > > +target in the CPPC performance scale as a relative number. This can > > +be expressed as percentage of nominal performance (infrastructure > > +max). Below the nominal sustained performance level, desired > > +performance expresses the average performance level of the processor > > +subject to the Performance Reduction Tolerance register. Above the > > +nominal performance level, processor must provide at least nominal > performance requested and go higher if current operating conditions allow. > > + > > + > > ``cpupower`` tool support for ``amd-pstate`` > > =============================================== > > [unhandled content-type:application/ms-tnef] | |