805 lines
48 KiB
ReStructuredText
805 lines
48 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
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.. include:: <isonum.txt>
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===============================================
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``amd-pstate`` CPU Performance Scaling Driver
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===============================================
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:Copyright: |copy| 2021 Advanced Micro Devices, Inc.
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:Author: Huang Rui <ray.huang@amd.com>
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Introduction
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===================
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``amd-pstate`` is the AMD CPU performance scaling driver that introduces a
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new CPU frequency control mechanism on modern AMD APU and CPU series in
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Linux kernel. The new mechanism is based on Collaborative Processor
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Performance Control (CPPC) which provides finer grain frequency management
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than legacy ACPI hardware P-States. Current AMD CPU/APU platforms are using
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the ACPI P-states driver to manage CPU frequency and clocks with switching
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only in 3 P-states. CPPC replaces the ACPI P-states controls and allows a
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flexible, low-latency interface for the Linux kernel to directly
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communicate the performance hints to hardware.
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``amd-pstate`` leverages the Linux kernel governors such as ``schedutil``,
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``ondemand``, etc. to manage the performance hints which are provided by
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CPPC hardware functionality that internally follows the hardware
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specification (for details refer to AMD64 Architecture Programmer's Manual
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Volume 2: System Programming [1]_). Currently, ``amd-pstate`` supports basic
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frequency control function according to kernel governors on some of the
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Zen2 and Zen3 processors, and we will implement more AMD specific functions
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in future after we verify them on the hardware and SBIOS.
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AMD CPPC Overview
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=======================
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Collaborative Processor Performance Control (CPPC) interface enumerates a
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continuous, abstract, and unit-less performance value in a scale that is
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not tied to a specific performance state / frequency. This is an ACPI
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standard [2]_ which software can specify application performance goals and
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hints as a relative target to the infrastructure limits. AMD processors
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provide the low latency register model (MSR) instead of an AML code
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interpreter for performance adjustments. ``amd-pstate`` will initialize a
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``struct cpufreq_driver`` instance, ``amd_pstate_driver``, with the callbacks
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to manage each performance update behavior. ::
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Highest Perf ------>+-----------------------+ +-----------------------+
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| | Max Perf ---->| |
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Nominal Perf ------>+-----------------------+ +-----------------------+
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| | Desired Perf ---->| |
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Lowest non- | | | |
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linear perf ------>+-----------------------+ +-----------------------+
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| | Lowest perf ---->| |
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Lowest perf ------>+-----------------------+ +-----------------------+
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0 ------>+-----------------------+ +-----------------------+
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AMD P-States Performance Scale
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.. _perf_cap:
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AMD CPPC Performance Capability
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--------------------------------
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Highest Performance (RO)
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.........................
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This is the absolute maximum performance an individual processor may reach,
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assuming ideal conditions. This performance level may not be sustainable
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for long durations and may only be achievable if other platform components
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are in a specific state; for example, it may require other processors to be in
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an idle state. This would be equivalent to the highest frequencies
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supported by the processor.
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Nominal (Guaranteed) Performance (RO)
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......................................
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This is the maximum sustained performance level of the processor, assuming
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ideal operating conditions. In the absence of an external constraint (power,
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thermal, etc.), this is the performance level the processor is expected to
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be able to maintain continuously. All cores/processors are expected to be
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able to sustain their nominal performance state simultaneously.
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Lowest non-linear Performance (RO)
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...................................
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This is the lowest performance level at which nonlinear power savings are
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achieved, for example, due to the combined effects of voltage and frequency
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scaling. Above this threshold, lower performance levels should be generally
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more energy efficient than higher performance levels. This register
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effectively conveys the most efficient performance level to ``amd-pstate``.
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Lowest Performance (RO)
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........................
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This is the absolute lowest performance level of the processor. Selecting a
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performance level lower than the lowest nonlinear performance level may
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cause an efficiency penalty but should reduce the instantaneous power
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consumption of the processor.
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AMD CPPC Performance Control
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------------------------------
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``amd-pstate`` passes performance goals through these registers. The
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register drives the behavior of the desired performance target.
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Minimum requested performance (RW)
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...................................
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``amd-pstate`` specifies the minimum allowed performance level.
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Maximum requested performance (RW)
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...................................
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``amd-pstate`` specifies a limit the maximum performance that is expected
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to be supplied by the hardware.
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Desired performance target (RW)
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...................................
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``amd-pstate`` specifies a desired target in the CPPC performance scale as
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a relative number. This can be expressed as percentage of nominal
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performance (infrastructure max). Below the nominal sustained performance
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level, desired performance expresses the average performance level of the
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processor subject to hardware. Above the nominal performance level,
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the processor must provide at least nominal performance requested and go higher
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if current operating conditions allow.
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Energy Performance Preference (EPP) (RW)
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.........................................
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This attribute provides a hint to the hardware if software wants to bias
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toward performance (0x0) or energy efficiency (0xff).
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Key Governors Support
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=======================
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``amd-pstate`` can be used with all the (generic) scaling governors listed
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by the ``scaling_available_governors`` policy attribute in ``sysfs``. Then,
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it is responsible for the configuration of policy objects corresponding to
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CPUs and provides the ``CPUFreq`` core (and the scaling governors attached
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to the policy objects) with accurate information on the maximum and minimum
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operating frequencies supported by the hardware. Users can check the
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``scaling_cur_freq`` information comes from the ``CPUFreq`` core.
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``amd-pstate`` mainly supports ``schedutil`` and ``ondemand`` for dynamic
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frequency control. It is to fine tune the processor configuration on
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``amd-pstate`` to the ``schedutil`` with CPU CFS scheduler. ``amd-pstate``
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registers the adjust_perf callback to implement performance update behavior
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similar to CPPC. It is initialized by ``sugov_start`` and then populates the
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CPU's update_util_data pointer to assign ``sugov_update_single_perf`` as the
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utilization update callback function in the CPU scheduler. The CPU scheduler
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will call ``cpufreq_update_util`` and assigns the target performance according
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to the ``struct sugov_cpu`` that the utilization update belongs to.
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Then, ``amd-pstate`` updates the desired performance according to the CPU
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scheduler assigned.
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.. _processor_support:
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Processor Support
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=======================
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The ``amd-pstate`` initialization will fail if the ``_CPC`` entry in the ACPI
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SBIOS does not exist in the detected processor. It uses ``acpi_cpc_valid``
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to check the existence of ``_CPC``. All Zen based processors support the legacy
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ACPI hardware P-States function, so when ``amd-pstate`` fails initialization,
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the kernel will fall back to initialize the ``acpi-cpufreq`` driver.
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There are two types of hardware implementations for ``amd-pstate``: one is
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`Full MSR Support <perf_cap_>`_ and another is `Shared Memory Support
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<perf_cap_>`_. It can use the :c:macro:`X86_FEATURE_CPPC` feature flag to
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indicate the different types. (For details, refer to the Processor Programming
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Reference (PPR) for AMD Family 19h Model 51h, Revision A1 Processors [3]_.)
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``amd-pstate`` is to register different ``static_call`` instances for different
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hardware implementations.
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Currently, some of the Zen2 and Zen3 processors support ``amd-pstate``. In the
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future, it will be supported on more and more AMD processors.
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Full MSR Support
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-----------------
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Some new Zen3 processors such as Cezanne provide the MSR registers directly
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while the :c:macro:`X86_FEATURE_CPPC` CPU feature flag is set.
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``amd-pstate`` can handle the MSR register to implement the fast switch
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function in ``CPUFreq`` that can reduce the latency of frequency control in
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interrupt context. The functions with a ``pstate_xxx`` prefix represent the
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operations on MSR registers.
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Shared Memory Support
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----------------------
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If the :c:macro:`X86_FEATURE_CPPC` CPU feature flag is not set, the
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processor supports the shared memory solution. In this case, ``amd-pstate``
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uses the ``cppc_acpi`` helper methods to implement the callback functions
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that are defined on ``static_call``. The functions with the ``cppc_xxx`` prefix
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represent the operations of ACPI CPPC helpers for the shared memory solution.
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AMD P-States and ACPI hardware P-States always can be supported in one
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processor. But AMD P-States has the higher priority and if it is enabled
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with :c:macro:`MSR_AMD_CPPC_ENABLE` or ``cppc_set_enable``, it will respond
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to the request from AMD P-States.
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User Space Interface in ``sysfs`` - Per-policy control
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======================================================
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``amd-pstate`` exposes several global attributes (files) in ``sysfs`` to
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control its functionality at the system level. They are located in the
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``/sys/devices/system/cpu/cpufreq/policyX/`` directory and affect all CPUs. ::
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root@hr-test1:/home/ray# ls /sys/devices/system/cpu/cpufreq/policy0/*amd*
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/sys/devices/system/cpu/cpufreq/policy0/amd_pstate_highest_perf
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/sys/devices/system/cpu/cpufreq/policy0/amd_pstate_lowest_nonlinear_freq
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/sys/devices/system/cpu/cpufreq/policy0/amd_pstate_max_freq
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``amd_pstate_highest_perf / amd_pstate_max_freq``
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Maximum CPPC performance and CPU frequency that the driver is allowed to
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set, in percent of the maximum supported CPPC performance level (the highest
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performance supported in `AMD CPPC Performance Capability <perf_cap_>`_).
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In some ASICs, the highest CPPC performance is not the one in the ``_CPC``
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table, so we need to expose it to sysfs. If boost is not active, but
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still supported, this maximum frequency will be larger than the one in
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``cpuinfo``. On systems that support preferred core, the driver will have
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different values for some cores than others and this will reflect the values
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advertised by the platform at bootup.
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This attribute is read-only.
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``amd_pstate_lowest_nonlinear_freq``
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The lowest non-linear CPPC CPU frequency that the driver is allowed to set,
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in percent of the maximum supported CPPC performance level. (Please see the
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lowest non-linear performance in `AMD CPPC Performance Capability
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<perf_cap_>`_.)
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This attribute is read-only.
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``amd_pstate_hw_prefcore``
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Whether the platform supports the preferred core feature and it has been
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enabled. This attribute is read-only.
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``amd_pstate_prefcore_ranking``
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The performance ranking of the core. This number doesn't have any unit, but
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larger numbers are preferred at the time of reading. This can change at
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runtime based on platform conditions. This attribute is read-only.
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``energy_performance_available_preferences``
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A list of all the supported EPP preferences that could be used for
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``energy_performance_preference`` on this system.
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These profiles represent different hints that are provided
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to the low-level firmware about the user's desired energy vs efficiency
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tradeoff. ``default`` represents the epp value is set by platform
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firmware. This attribute is read-only.
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``energy_performance_preference``
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The current energy performance preference can be read from this attribute.
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and user can change current preference according to energy or performance needs
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Please get all support profiles list from
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``energy_performance_available_preferences`` attribute, all the profiles are
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integer values defined between 0 to 255 when EPP feature is enabled by platform
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firmware, if EPP feature is disabled, driver will ignore the written value
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This attribute is read-write.
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``boost``
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The `boost` sysfs attribute provides control over the CPU core
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performance boost, allowing users to manage the maximum frequency limitation
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of the CPU. This attribute can be used to enable or disable the boost feature
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on individual CPUs.
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When the boost feature is enabled, the CPU can dynamically increase its frequency
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beyond the base frequency, providing enhanced performance for demanding workloads.
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On the other hand, disabling the boost feature restricts the CPU to operate at the
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base frequency, which may be desirable in certain scenarios to prioritize power
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efficiency or manage temperature.
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To manipulate the `boost` attribute, users can write a value of `0` to disable the
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boost or `1` to enable it, for the respective CPU using the sysfs path
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`/sys/devices/system/cpu/cpuX/cpufreq/boost`, where `X` represents the CPU number.
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Other performance and frequency values can be read back from
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``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.
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``amd-pstate`` vs ``acpi-cpufreq``
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======================================
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On the majority of AMD platforms supported by ``acpi-cpufreq``, the ACPI tables
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provided by the platform firmware are used for CPU performance scaling, but
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only provide 3 P-states on AMD processors.
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However, on modern AMD APU and CPU series, hardware provides the Collaborative
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Processor Performance Control according to the ACPI protocol and customizes this
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for AMD platforms. That is, fine-grained and continuous frequency ranges
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instead of the legacy hardware P-states. ``amd-pstate`` is the kernel
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module which supports the new AMD P-States mechanism on most of the future AMD
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platforms. The AMD P-States mechanism is the more performance and energy
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efficiency frequency management method on AMD processors.
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``amd-pstate`` Driver Operation Modes
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======================================
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``amd_pstate`` CPPC has 3 operation modes: autonomous (active) mode,
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non-autonomous (passive) mode and guided autonomous (guided) mode.
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Active/passive/guided mode can be chosen by different kernel parameters.
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- In autonomous mode, platform ignores the desired performance level request
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and takes into account only the values set to the minimum, maximum and energy
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performance preference registers.
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- In non-autonomous mode, platform gets desired performance level
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from OS directly through Desired Performance Register.
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- In guided-autonomous mode, platform sets operating performance level
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autonomously according to the current workload and within the limits set by
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OS through min and max performance registers.
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Active Mode
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------------
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``amd_pstate=active``
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This is the low-level firmware control mode which is implemented by ``amd_pstate_epp``
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driver with ``amd_pstate=active`` passed to the kernel in the command line.
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In this mode, ``amd_pstate_epp`` driver provides a hint to the hardware if software
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wants to bias toward performance (0x0) or energy efficiency (0xff) to the CPPC firmware.
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then CPPC power algorithm will calculate the runtime workload and adjust the realtime
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cores frequency according to the power supply and thermal, core voltage and some other
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hardware conditions.
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Passive Mode
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------------
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``amd_pstate=passive``
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It will be enabled if the ``amd_pstate=passive`` is passed to the kernel in the command line.
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In this mode, ``amd_pstate`` driver software specifies a desired QoS target in the CPPC
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performance scale as a relative number. This can be expressed as percentage of nominal
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performance (infrastructure max). Below the nominal sustained performance level,
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desired performance expresses the average performance level of the processor subject
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to the Performance Reduction Tolerance register. Above the nominal performance level,
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processor must provide at least nominal performance requested and go higher if current
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operating conditions allow.
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Guided Mode
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-----------
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``amd_pstate=guided``
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If ``amd_pstate=guided`` is passed to kernel command line option then this mode
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is activated. In this mode, driver requests minimum and maximum performance
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level and the platform autonomously selects a performance level in this range
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and appropriate to the current workload.
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``amd-pstate`` Preferred Core
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=================================
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The core frequency is subjected to the process variation in semiconductors.
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Not all cores are able to reach the maximum frequency respecting the
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infrastructure limits. Consequently, AMD has redefined the concept of
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maximum frequency of a part. This means that a fraction of cores can reach
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maximum frequency. To find the best process scheduling policy for a given
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scenario, OS needs to know the core ordering informed by the platform through
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highest performance capability register of the CPPC interface.
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``amd-pstate`` preferred core enables the scheduler to prefer scheduling on
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cores that can achieve a higher frequency with lower voltage. The preferred
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core rankings can dynamically change based on the workload, platform conditions,
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thermals and ageing.
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The priority metric will be initialized by the ``amd-pstate`` driver. The ``amd-pstate``
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driver will also determine whether or not ``amd-pstate`` preferred core is
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supported by the platform.
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``amd-pstate`` driver will provide an initial core ordering when the system boots.
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The platform uses the CPPC interfaces to communicate the core ranking to the
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operating system and scheduler to make sure that OS is choosing the cores
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with highest performance firstly for scheduling the process. When ``amd-pstate``
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driver receives a message with the highest performance change, it will
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update the core ranking and set the cpu's priority.
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``amd-pstate`` Preferred Core Switch
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=====================================
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Kernel Parameters
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-----------------
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``amd-pstate`` peferred core`` has two states: enable and disable.
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Enable/disable states can be chosen by different kernel parameters.
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Default enable ``amd-pstate`` preferred core.
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``amd_prefcore=disable``
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For systems that support ``amd-pstate`` preferred core, the core rankings will
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always be advertised by the platform. But OS can choose to ignore that via the
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kernel parameter ``amd_prefcore=disable``.
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User Space Interface in ``sysfs`` - General
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===========================================
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Global Attributes
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-----------------
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``amd-pstate`` exposes several global attributes (files) in ``sysfs`` to
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control its functionality at the system level. They are located in the
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``/sys/devices/system/cpu/amd_pstate/`` directory and affect all CPUs.
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``status``
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Operation mode of the driver: "active", "passive", "guided" or "disable".
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"active"
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The driver is functional and in the ``active mode``
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"passive"
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The driver is functional and in the ``passive mode``
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"guided"
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The driver is functional and in the ``guided mode``
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"disable"
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The driver is unregistered and not functional now.
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This attribute can be written to in order to change the driver's
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operation mode or to unregister it. The string written to it must be
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one of the possible values of it and, if successful, writing one of
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these values to the sysfs file will cause the driver to switch over
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to the operation mode represented by that string - or to be
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unregistered in the "disable" case.
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``prefcore``
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Preferred core state of the driver: "enabled" or "disabled".
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"enabled"
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Enable the ``amd-pstate`` preferred core.
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"disabled"
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Disable the ``amd-pstate`` preferred core
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This attribute is read-only to check the state of preferred core set
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by the kernel parameter.
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``cpupower`` tool support for ``amd-pstate``
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===============================================
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``amd-pstate`` is supported by the ``cpupower`` tool, which can be used to dump
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frequency information. Development is in progress to support more and more
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operations for the new ``amd-pstate`` module with this tool. ::
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root@hr-test1:/home/ray# cpupower frequency-info
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analyzing CPU 0:
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driver: amd-pstate
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CPUs which run at the same hardware frequency: 0
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CPUs which need to have their frequency coordinated by software: 0
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maximum transition latency: 131 us
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hardware limits: 400 MHz - 4.68 GHz
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available cpufreq governors: ondemand conservative powersave userspace performance schedutil
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current policy: frequency should be within 400 MHz and 4.68 GHz.
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The governor "schedutil" may decide which speed to use
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within this range.
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current CPU frequency: Unable to call hardware
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current CPU frequency: 4.02 GHz (asserted by call to kernel)
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boost state support:
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Supported: yes
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Active: yes
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AMD PSTATE Highest Performance: 166. Maximum Frequency: 4.68 GHz.
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AMD PSTATE Nominal Performance: 117. Nominal Frequency: 3.30 GHz.
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AMD PSTATE Lowest Non-linear Performance: 39. Lowest Non-linear Frequency: 1.10 GHz.
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AMD PSTATE Lowest Performance: 15. Lowest Frequency: 400 MHz.
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Diagnostics and Tuning
|
|
=======================
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Trace Events
|
|
--------------
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|
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There are two static trace events that can be used for ``amd-pstate``
|
|
diagnostics. One of them is the ``cpu_frequency`` trace event generally used
|
|
by ``CPUFreq``, and the other one is the ``amd_pstate_perf`` trace event
|
|
specific to ``amd-pstate``. The following sequence of shell commands can
|
|
be used to enable them and see their output (if the kernel is
|
|
configured to support event tracing). ::
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root@hr-test1:/home/ray# cd /sys/kernel/tracing/
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root@hr-test1:/sys/kernel/tracing# echo 1 > events/amd_cpu/enable
|
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root@hr-test1:/sys/kernel/tracing# cat trace
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# tracer: nop
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#
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# entries-in-buffer/entries-written: 47827/42233061 #P:2
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#
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# _-----=> irqs-off
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# / _----=> need-resched
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# | / _---=> hardirq/softirq
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# || / _--=> preempt-depth
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# ||| / delay
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# TASK-PID CPU# |||| TIMESTAMP FUNCTION
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# | | | |||| | |
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<idle>-0 [015] dN... 4995.979886: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=15 changed=false fast_switch=true
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|
<idle>-0 [007] d.h.. 4995.979893: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=7 changed=false fast_switch=true
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|
cat-2161 [000] d.... 4995.980841: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=0 changed=false fast_switch=true
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sshd-2125 [004] d.s.. 4995.980968: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=4 changed=false fast_switch=true
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|
<idle>-0 [007] d.s.. 4995.980968: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=7 changed=false fast_switch=true
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|
<idle>-0 [003] d.s.. 4995.980971: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=3 changed=false fast_switch=true
|
|
<idle>-0 [011] d.s.. 4995.980996: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=11 changed=false fast_switch=true
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The ``cpu_frequency`` trace event will be triggered either by the ``schedutil`` scaling
|
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governor (for the policies it is attached to), or by the ``CPUFreq`` core (for the
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|
policies with other scaling governors).
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|
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Tracer Tool
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|
-------------
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|
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|
``amd_pstate_tracer.py`` can record and parse ``amd-pstate`` trace log, then
|
|
generate performance plots. This utility can be used to debug and tune the
|
|
performance of ``amd-pstate`` driver. The tracer tool needs to import intel
|
|
pstate tracer.
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|
|
Tracer tool located in ``linux/tools/power/x86/amd_pstate_tracer``. It can be
|
|
used in two ways. If trace file is available, then directly parse the file
|
|
with command ::
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|
|
./amd_pstate_trace.py [-c cpus] -t <trace_file> -n <test_name>
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|
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Or generate trace file with root privilege, then parse and plot with command ::
|
|
|
|
sudo ./amd_pstate_trace.py [-c cpus] -n <test_name> -i <interval> [-m kbytes]
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|
|
The test result can be found in ``results/test_name``. Following is the example
|
|
about part of the output. ::
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|
common_cpu common_secs common_usecs min_perf des_perf max_perf freq mperf apef tsc load duration_ms sample_num elapsed_time common_comm
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CPU_005 712 116384 39 49 166 0.7565 9645075 2214891 38431470 25.1 11.646 469 2.496 kworker/5:0-40
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|
CPU_006 712 116408 39 49 166 0.6769 8950227 1839034 37192089 24.06 11.272 470 2.496 kworker/6:0-1264
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|
|
Unit Tests for amd-pstate
|
|
-------------------------
|
|
|
|
``amd-pstate-ut`` is a test module for testing the ``amd-pstate`` driver.
|
|
|
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* It can help all users to verify their processor support (SBIOS/Firmware or Hardware).
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* Kernel can have a basic function test to avoid the kernel regression during the update.
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* We can introduce more functional or performance tests to align the result together, it will benefit power and performance scale optimization.
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|
|
|
1. Test case descriptions
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|
|
1). Basic tests
|
|
|
|
Test prerequisite and basic functions for the ``amd-pstate`` driver.
|
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|
|
+---------+--------------------------------+------------------------------------------------------------------------------------+
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|
| Index | Functions | Description |
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|
+=========+================================+====================================================================================+
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| 1 | amd_pstate_ut_acpi_cpc_valid || Check whether the _CPC object is present in SBIOS. |
|
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| | || |
|
|
| | || The detail refer to `Processor Support <processor_support_>`_. |
|
|
+---------+--------------------------------+------------------------------------------------------------------------------------+
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| 2 | amd_pstate_ut_check_enabled || Check whether AMD P-State is enabled. |
|
|
| | || |
|
|
| | || AMD P-States and ACPI hardware P-States always can be supported in one processor. |
|
|
| | | But AMD P-States has the higher priority and if it is enabled with |
|
|
| | | :c:macro:`MSR_AMD_CPPC_ENABLE` or ``cppc_set_enable``, it will respond to the |
|
|
| | | request from AMD P-States. |
|
|
+---------+--------------------------------+------------------------------------------------------------------------------------+
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|
| 3 | amd_pstate_ut_check_perf || Check if the each performance values are reasonable. |
|
|
| | || highest_perf >= nominal_perf > lowest_nonlinear_perf > lowest_perf > 0. |
|
|
+---------+--------------------------------+------------------------------------------------------------------------------------+
|
|
| 4 | amd_pstate_ut_check_freq || Check if the each frequency values and max freq when set support boost mode |
|
|
| | | are reasonable. |
|
|
| | || max_freq >= nominal_freq > lowest_nonlinear_freq > min_freq > 0 |
|
|
| | || If boost is not active but supported, this maximum frequency will be larger than |
|
|
| | | the one in ``cpuinfo``. |
|
|
+---------+--------------------------------+------------------------------------------------------------------------------------+
|
|
|
|
2). Tbench test
|
|
|
|
Test and monitor the cpu changes when running tbench benchmark under the specified governor.
|
|
These changes include desire performance, frequency, load, performance, energy etc.
|
|
The specified governor is ondemand or schedutil.
|
|
Tbench can also be tested on the ``acpi-cpufreq`` kernel driver for comparison.
|
|
|
|
3). Gitsource test
|
|
|
|
Test and monitor the cpu changes when running gitsource benchmark under the specified governor.
|
|
These changes include desire performance, frequency, load, time, energy etc.
|
|
The specified governor is ondemand or schedutil.
|
|
Gitsource can also be tested on the ``acpi-cpufreq`` kernel driver for comparison.
|
|
|
|
#. How to execute the tests
|
|
|
|
We use test module in the kselftest frameworks to implement it.
|
|
We create ``amd-pstate-ut`` module and tie it into kselftest.(for
|
|
details refer to Linux Kernel Selftests [4]_).
|
|
|
|
1). Build
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|
|
|
+ open the :c:macro:`CONFIG_X86_AMD_PSTATE` configuration option.
|
|
+ set the :c:macro:`CONFIG_X86_AMD_PSTATE_UT` configuration option to M.
|
|
+ make project
|
|
+ make selftest ::
|
|
|
|
$ cd linux
|
|
$ make -C tools/testing/selftests
|
|
|
|
+ make perf ::
|
|
|
|
$ cd tools/perf/
|
|
$ make
|
|
|
|
|
|
2). Installation & Steps ::
|
|
|
|
$ make -C tools/testing/selftests install INSTALL_PATH=~/kselftest
|
|
$ cp tools/perf/perf /usr/bin/perf
|
|
$ sudo ./kselftest/run_kselftest.sh -c amd-pstate
|
|
|
|
3). Specified test case ::
|
|
|
|
$ cd ~/kselftest/amd-pstate
|
|
$ sudo ./run.sh -t basic
|
|
$ sudo ./run.sh -t tbench
|
|
$ sudo ./run.sh -t tbench -m acpi-cpufreq
|
|
$ sudo ./run.sh -t gitsource
|
|
$ sudo ./run.sh -t gitsource -m acpi-cpufreq
|
|
$ ./run.sh --help
|
|
./run.sh: illegal option -- -
|
|
Usage: ./run.sh [OPTION...]
|
|
[-h <help>]
|
|
[-o <output-file-for-dump>]
|
|
[-c <all: All testing,
|
|
basic: Basic testing,
|
|
tbench: Tbench testing,
|
|
gitsource: Gitsource testing.>]
|
|
[-t <tbench time limit>]
|
|
[-p <tbench process number>]
|
|
[-l <loop times for tbench>]
|
|
[-i <amd tracer interval>]
|
|
[-m <comparative test: acpi-cpufreq>]
|
|
|
|
|
|
4). Results
|
|
|
|
+ basic
|
|
|
|
When you finish test, you will get the following log info ::
|
|
|
|
$ dmesg | grep "amd_pstate_ut" | tee log.txt
|
|
[12977.570663] amd_pstate_ut: 1 amd_pstate_ut_acpi_cpc_valid success!
|
|
[12977.570673] amd_pstate_ut: 2 amd_pstate_ut_check_enabled success!
|
|
[12977.571207] amd_pstate_ut: 3 amd_pstate_ut_check_perf success!
|
|
[12977.571212] amd_pstate_ut: 4 amd_pstate_ut_check_freq success!
|
|
|
|
+ tbench
|
|
|
|
When you finish test, you will get selftest.tbench.csv and png images.
|
|
The selftest.tbench.csv file contains the raw data and the drop of the comparative test.
|
|
The png images shows the performance, energy and performan per watt of each test.
|
|
Open selftest.tbench.csv :
|
|
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ Governor | Round | Des-perf | Freq | Load | Performance | Energy | Performance Per Watt |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ Unit | | | GHz | | MB/s | J | MB/J |
|
|
+=================================================+==============+==========+=========+==========+=============+=========+======================+
|
|
+ amd-pstate-ondemand | 1 | | | | 2504.05 | 1563.67 | 158.5378 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-ondemand | 2 | | | | 2243.64 | 1430.32 | 155.2941 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-ondemand | 3 | | | | 2183.88 | 1401.32 | 154.2860 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-ondemand | Average | | | | 2310.52 | 1465.1 | 156.1268 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-schedutil | 1 | 165.329 | 1.62257 | 99.798 | 2136.54 | 1395.26 | 151.5971 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-schedutil | 2 | 166 | 1.49761 | 99.9993 | 2100.56 | 1380.5 | 150.6377 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-schedutil | 3 | 166 | 1.47806 | 99.9993 | 2084.12 | 1375.76 | 149.9737 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-schedutil | Average | 165.776 | 1.53275 | 99.9322 | 2107.07 | 1383.84 | 150.7399 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-ondemand | 1 | | | | 2529.9 | 1564.4 | 160.0997 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-ondemand | 2 | | | | 2249.76 | 1432.97 | 155.4297 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-ondemand | 3 | | | | 2181.46 | 1406.88 | 153.5060 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-ondemand | Average | | | | 2320.37 | 1468.08 | 156.4741 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-schedutil | 1 | | | | 2137.64 | 1385.24 | 152.7723 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-schedutil | 2 | | | | 2107.05 | 1372.23 | 152.0138 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-schedutil | 3 | | | | 2085.86 | 1365.35 | 151.2433 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-schedutil | Average | | | | 2110.18 | 1374.27 | 152.0136 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-ondemand VS acpi-cpufreq-schedutil | Comprison(%) | | | | -9.0584 | -6.3899 | -2.8506 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-ondemand VS amd-pstate-schedutil | Comprison(%) | | | | 8.8053 | -5.5463 | -3.4503 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-ondemand VS amd-pstate-ondemand | Comprison(%) | | | | -0.4245 | -0.2029 | -0.2219 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-schedutil VS amd-pstate-schedutil | Comprison(%) | | | | -0.1473 | 0.6963 | -0.8378 |
|
|
+-------------------------------------------------+--------------+----------+---------+----------+-------------+---------+----------------------+
|
|
|
|
+ gitsource
|
|
|
|
When you finish test, you will get selftest.gitsource.csv and png images.
|
|
The selftest.gitsource.csv file contains the raw data and the drop of the comparative test.
|
|
The png images shows the performance, energy and performan per watt of each test.
|
|
Open selftest.gitsource.csv :
|
|
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ Governor | Round | Des-perf | Freq | Load | Time | Energy | Performance Per Watt |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ Unit | | | GHz | | s | J | 1/J |
|
|
+=================================================+==============+==========+==========+==========+=============+=========+======================+
|
|
+ amd-pstate-ondemand | 1 | 50.119 | 2.10509 | 23.3076 | 475.69 | 865.78 | 0.001155027 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-ondemand | 2 | 94.8006 | 1.98771 | 56.6533 | 467.1 | 839.67 | 0.001190944 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-ondemand | 3 | 76.6091 | 2.53251 | 43.7791 | 467.69 | 855.85 | 0.001168429 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-ondemand | Average | 73.8429 | 2.20844 | 41.2467 | 470.16 | 853.767 | 0.001171279 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-schedutil | 1 | 165.919 | 1.62319 | 98.3868 | 464.17 | 866.8 | 0.001153668 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-schedutil | 2 | 165.97 | 1.31309 | 99.5712 | 480.15 | 880.4 | 0.001135847 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-schedutil | 3 | 165.973 | 1.28448 | 99.9252 | 481.79 | 867.02 | 0.001153375 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-schedutil | Average | 165.954 | 1.40692 | 99.2944 | 475.37 | 871.407 | 0.001147569 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-ondemand | 1 | | | | 2379.62 | 742.96 | 0.001345967 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-ondemand | 2 | | | | 441.74 | 817.49 | 0.001223256 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-ondemand | 3 | | | | 455.48 | 820.01 | 0.001219497 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-ondemand | Average | | | | 425.613 | 793.487 | 0.001260260 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-schedutil | 1 | | | | 459.69 | 838.54 | 0.001192548 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-schedutil | 2 | | | | 466.55 | 830.89 | 0.001203528 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-schedutil | 3 | | | | 470.38 | 837.32 | 0.001194286 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-schedutil | Average | | | | 465.54 | 835.583 | 0.001196769 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-ondemand VS acpi-cpufreq-schedutil | Comprison(%) | | | | 9.3810 | 5.3051 | -5.0379 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ amd-pstate-ondemand VS amd-pstate-schedutil | Comprison(%) | 124.7392 | -36.2934 | 140.7329 | 1.1081 | 2.0661 | -2.0242 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-ondemand VS amd-pstate-ondemand | Comprison(%) | | | | 10.4665 | 7.5968 | -7.0605 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
+ acpi-cpufreq-schedutil VS amd-pstate-schedutil | Comprison(%) | | | | 2.1115 | 4.2873 | -4.1110 |
|
|
+-------------------------------------------------+--------------+----------+----------+----------+-------------+---------+----------------------+
|
|
|
|
Reference
|
|
===========
|
|
|
|
.. [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming,
|
|
https://www.amd.com/system/files/TechDocs/24593.pdf
|
|
|
|
.. [2] Advanced Configuration and Power Interface Specification,
|
|
https://uefi.org/sites/default/files/resources/ACPI_Spec_6_4_Jan22.pdf
|
|
|
|
.. [3] Processor Programming Reference (PPR) for AMD Family 19h Model 51h, Revision A1 Processors
|
|
https://www.amd.com/system/files/TechDocs/56569-A1-PUB.zip
|
|
|
|
.. [4] Linux Kernel Selftests,
|
|
https://www.kernel.org/doc/html/latest/dev-tools/kselftest.html
|