More Accurate Load Tracking Being Worked On For the ACPI CPPC CPUFreq Driver

Written by Michael Larabel in Linux Kernel on 10 July 2020 at 07:04 AM EDT. Add A Comment
The ACPI CPPC (Collaborative Processor Performance Control) Linux CPUFreq driver continues to be improved upon.

CPPC is the ACPI specification around OS management of describing abstract performance scales and a means of being able to request higher/lower performance levels and measuring per-CPU performance. The Linux kernel for a while has offered the ACPI CPPC CPUFreq driver for making use of this standard on supported systems for frequency scaling. So far mostly Arm Linux systems have leveraged ACPI CPPC CPUFreq while last year AMD proposed their own CPPC driver albeit at the moment appears stalled.

We have seen work in recent times by ARM stakeholders on improving CPPC CPUFreq with the likes of boost support while the latest being tackled by the Linaro crew is on frequency invariance. The frequency invariance for CPPC CPUFreq is aiming to deliver more accurate load tracking to make better CPU frequency scaling decisions.

This includes support for ARM systems lacking Activity Monitor Units (AMU) that also provide similar frequency invariance support. The tentative work in this area can be found via this patch series.
Related News
About The Author
Michael Larabel

Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

Popular News This Week