Linux cpupower Tool Being Extended For AMD P-State Features

The cpupower tool that lives within the Linux kernel source tree can be used for easily querying and setting various CPU power-related features. This tool now has patches pending for extending it for exposing more functionality found within AMD's modern P-State CPU frequency scaling driver.

The cpupower tool's commands already work on AMD processors for reading and setting various power/frequency related features while the AMD P-State driver opens the door to some new tunables that can be easily integrated with cpupower for user/administrator convenience rather than interfacing with sysfs directly.

The new patches from AMD allow for cpupower to support controlling the ACPI Energy Performance Preference (EPP) value, which is also available for the Intel P-State driver when operating in the Active mode. The cpupower patches also allow configuring the AMD P-State driver's operating mode whether it be active, passive, or in the guided autonomous mode. Lastly is support for adjusting the Turbo Boost feature with AMD P-State, which is enabled by default but for those that may want to check on its status and/or disable it.

The proposed patches to cpupower are now out for review on the Linux power management mailing list. With the cpupower set command, the new options are accessible via the --epp, --amd-pstate-mode, and --turbo-boost switches.

In other AMD Linux power management news has also been this patch for helping to ensure AMD P-State defaults to using the scheduler utilization "schedutil" data even if Intel P-State isn't built as part of the kernel.