amd_epp_tool AMD pstate CPU Performance Scaling

This small tool is a simple CLI and TUI to configure the scaling_governor and energy_performance_preference settings exposed in sysfs by the Linux amd_pstate_epp driver. It sets the same profile uniformly across all CPUs.

Usage

It has 4 commands, note that making a configuration change requires root access.

Read or change the amd_pstate_epp kernel driver settings

Usage: amd-epp-tool [COMMAND]

Commands:
  ui    interactive settings UI (default)
  get   get the current settings
  set   set new settings
  mon   CPU Frequency monitor graph
  help  Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

Installation

Linux

The latest release can be "installed" by placing it in your user path $HOME/.local/bin/ and made setuid root as such:

curl -L https://github.com/jayv/amd-epp-tool/releases/latest/\
download/amd-epp-tool-x86_64-unknown-linux-gnu.tar.gz | tar zxv -C $HOME/.local/bin/

# make it setuid root to change settings (optional) 
sudo chown root $HOME/.local/bin/amd-epp-tool
sudo chmod +s $HOME/.local/bin/amd-epp-tool

Alternative installation (global path, use sudo when changing settings):

curl -L https://github.com/jayv/amd-epp-tool/releases/latest/\
download/amd-epp-tool-x86_64-unknown-linux-gnu.tar.gz | sudo tar zxv -C /usr/local/bin/

Other Operating Systems

This tool is only for the Linux amd_pstate_epp driver, sorry.

Gotchas

This tool is built specifically to work with the amd_pstate_epp driver in active mode, which was introduced in Linux 6.3 or available as a patch against 5.x if you compiled your own kernel.

The allowed combination of scaling_governor and energy_performance_preference (epp) settings is dictated by the driver, if you receive a device or resource busy message, that usually means you've chosen an invalid configuration combination, eg. mixing performance and power-saving:

> amd-epp-tool set -s=performance -e=power
Failed to save configuration, perhaps you need ROOT access
Error Device or resource busy (os error 16)

The tool doesn't prevent partial updates. If it fails to apply a setting, which usually means some incompatible energy_performance_preference combination which got rejected, it may have already updated your scaling_governor. It makes no effort to roll back to the prior state.