AMDGPU Clocks

Introduction

This is a simple script that can be used to set custom power states for recent AMD GPUs that are driven by amdgpu or amdgpu-pro Linux drivers. The script is able to set custom clocks, voltages and some other power states, assuming that amdgpu.ppfeaturemask=0xffffffff kernel option is being set, which in turn enables amdgpu driver sysfs API that allows fine grain control of GPU power states (GPU & VRAM clocks & voltages, depending on actual hardware). It should work on Polaris (well tested) and Vega cards, and it can be used to easily manage multiple cards.

How does it work

By default, custom power states are defined in files that are expected to reside in /etc/default/amdgpu-custom-state.cardX, where X corresponds to a card in /sys/class/drm/cardX. The custom state files have same format as the actual /sys/class/drm/cardX/device/pp_od_clk_voltage, with option to add newlines, comments (lines starting with #) and three extra parameters, used to set extra power state details. These are FORCE_SCLK & FORCE_MCLK, that can be used to limit GPU and memory power states to a particular subset of states, and FORCE_LEVEL, that can be used to force desired power_dpm_force_performance_level of a card (which can be auto, low, high, manual, etc).

Here is an example how custom power state definition file may look like:

$ cat /etc/default/radeon-custom-states.card0
# Set custom GPU states 6 & 7:
OD_SCLK:
6:       1000MHz        860mV
7:       1050MHz        890mV
# Set custom memory states 1 & 2:
OD_MCLK:
1:        900MHz        800mV
2:       1600MHz        900mV
# Only allow SCLK states 5, 6 & 7:
FORCE_SCLK: 5 6 7
# Force fixed memory state:
FORCE_MCLK: 2
# In order to allow FORCE_SCLK & FORCE_MCLK:
FORCE_LEVEL: manual

Installing and manually running the script

Simply place the script in /usr/bin/amdgpu-clocks, and specify custom power states in /etc/default/radeon-custom-states.card0:

# amdgpu-clocks
Detecting the state values at /sys/class/drm/card0/device/pp_od_clk_voltage:
  SCLK state 0: 300MHz, 750mV
  SCLK state 1: 500MHz, 775mV
  SCLK state 2: 600MHz, 785mV
  SCLK state 3: 700MHz, 800mV
  SCLK state 4: 800MHz, 820mV
  SCLK state 5: 900MHz, 840mV
  SCLK state 6: 950MHz, 850mV
  SCLK state 7: 1000MHz, 860mV
  MCLK state 0: 300MHz, 750mV
  MCLK state 1: 1000MHz, 800mV
  MCLK state 2: 1750MHz, 900mV
  Maximum clocks & voltages:
    SCLK clock 2000MHz
    MCLK clock 2250MHz
    VDDC voltage 1150mV
Verifying user state values at radeon-custom-states.card0:
  SCLK state 6: 1000MHz, 860mV
  SCLK state 7: 1050MHz, 890mV
  MCLK state 2: 1600MHz, 900mV
  Force SCLK state to 5 6 7
  Force MCLK state to 2
  Force performance level to manual
Committing custom states to /sys/class/drm/card0/device/pp_od_clk_voltage:
  Done

The script can also be invoked with specific custom state file prefix (can be a directory, case trailing slash is supplied), for example:

$ sudo USER_STATES_PATH=custom-states amdgpu-clocks

This will load and apply custom states from all custom-states.card* files in the current directory.

Making the custom power states persist

This can be achieved by placing provided systemd service file in /lib/systemd/system/ directory, and enable it:

# systemctl enable amdgpu-clocks

Of course, one should not forget to place the actual custom power states in /etc/default/amdgpu-custom-state.cardX.