diff options
| author | Wyes Karny <wyes.karny@amd.com> | 2023-03-07 11:27:38 +0000 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2023-03-17 19:06:23 +0100 |
| commit | 2dd6d0ebf74049256160a3d03dabbd92fe0b8599 (patch) | |
| tree | b4e11ac524326526e89b7f57cc0816611839a817 /Documentation/admin-guide | |
| parent | 3e6e078057640751654bda9fd2278a944f61fa4a (diff) | |
| download | linux-stable-2dd6d0ebf74049256160a3d03dabbd92fe0b8599.tar.gz linux-stable-2dd6d0ebf74049256160a3d03dabbd92fe0b8599.tar.bz2 linux-stable-2dd6d0ebf74049256160a3d03dabbd92fe0b8599.zip | |
cpufreq: amd-pstate: Add guided autonomous mode
From ACPI spec below 3 modes for CPPC can be defined:
1. Non autonomous: OS scaling governor specifies operating frequency/
performance level through `Desired Performance` register and platform
follows that.
2. Guided autonomous: OS scaling governor specifies min and max
frequencies/ performance levels through `Minimum Performance` and
`Maximum Performance` register, and platform can autonomously select an
operating frequency in this range.
3. Fully autonomous: OS only hints (via EPP) to platform for the required
energy performance preference for the workload and platform autonomously
scales the frequency.
Currently (1) is supported by amd_pstate as passive mode, and (3) is
implemented by EPP support. This change is to support (2).
In guided autonomous mode the min_perf is based on the input from the
scaling governor. For example, in case of schedutil this value depends
on the current utilization. And max_perf is set to max capacity.
To activate guided auto mode ``amd_pstate=guided`` command line
parameter has to be passed in the kernel.
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 1e38f3ae0e62..1e5fe4891dd7 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -344,11 +344,11 @@ 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.) + 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 @@ -356,6 +356,11 @@ 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 |