diff options
author | Rafael J. Wysocki | 2023-04-14 17:18:07 +0200 |
---|---|---|
committer | Rafael J. Wysocki | 2023-04-14 17:18:07 +0200 |
commit | 684952212ca639bce124e673f9f644a09895359c (patch) | |
tree | d69b9291f10610ad4c71393ed71fabed91f07f70 /Documentation/admin-guide | |
parent | 4654e9f9f43993eb9ce383fa7c88d14b052b8cc3 (diff) | |
parent | 11fa52fe619acfa945712d94a0bc27c0f5bc49de (diff) |
Merge back cpufreq changes for 6.4-rc1.
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 40 | ||||
-rw-r--r-- | Documentation/admin-guide/pm/amd-pstate.rst | 31 |
2 files changed, 47 insertions, 24 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 6221a1d057dd..1e5fe4891dd7 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -339,6 +339,29 @@ This mode requires kvm-amd.avic=1. (Default when IOMMU HW support is present.) + amd_pstate= [X86] + disable + Do not enable amd_pstate as the default + scaling driver for the supported processors + passive + Use amd_pstate with passive mode as a scaling driver. + In this mode autonomous selection is disabled. + Driver requests a desired performance level and platform + tries to match the same performance level if it is + satisfied by guaranteed performance level. + active + Use amd_pstate_epp driver instance as the scaling driver, + 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. + guided + Activate guided autonomous mode. Driver requests minimum and + maximum performance level and the platform autonomously + selects a performance level in this range and appropriate + to the current workload. + amijoy.map= [HW,JOY] Amiga joystick support Map of devices attached to JOY0DAT and JOY1DAT Format: <a>,<b> @@ -7059,20 +7082,3 @@ xmon commands. off xmon is disabled. - amd_pstate= [X86] - disable - Do not enable amd_pstate as the default - scaling driver for the supported processors - passive - Use amd_pstate as a scaling driver, driver requests a - desired performance on this abstract scale and the power - management firmware translates the requests into actual - hardware states (core frequency, data fabric and memory - clocks etc.) - active - Use amd_pstate_epp driver instance as the scaling driver, - 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. diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst index 6e5298b521b1..1cf40f69278c 100644 --- a/Documentation/admin-guide/pm/amd-pstate.rst +++ b/Documentation/admin-guide/pm/amd-pstate.rst @@ -303,13 +303,18 @@ efficiency frequency management method on AMD processors. AMD Pstate Driver Operation Modes ================================= -``amd_pstate`` CPPC has two operation modes: CPPC Autonomous(active) mode and -CPPC non-autonomous(passive) mode. -active mode and passive mode 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. +``amd_pstate`` CPPC has 3 operation modes: autonomous (active) mode, +non-autonomous (passive) mode and guided autonomous (guided) mode. +Active/passive/guided mode can be chosen by different kernel parameters. + +- In autonomous mode, platform ignores the desired performance level request + and takes into account only the values set to the minimum, maximum and energy + performance preference registers. +- In non-autonomous mode, platform gets desired performance level + from OS directly through Desired Performance Register. +- In guided-autonomous mode, platform sets operating performance level + autonomously according to the current workload and within the limits set by + OS through min and max performance registers. Active Mode ------------ @@ -338,6 +343,15 @@ to the Performance Reduction Tolerance register. Above the nominal performance l processor must provide at least nominal performance requested and go higher if current operating conditions allow. +Guided Mode +----------- + +``amd_pstate=guided`` + +If ``amd_pstate=guided`` is passed to kernel command line option then this mode +is activated. In this mode, driver requests minimum and maximum performance +level and the platform autonomously selects a performance level in this range +and appropriate to the current workload. User Space Interface in ``sysfs`` - General =========================================== @@ -358,6 +372,9 @@ control its functionality at the system level. They are located in the "passive" The driver is functional and in the ``passive mode`` + "guided" + The driver is functional and in the ``guided mode`` + "disable" The driver is unregistered and not functional now. |