Arm Proposes ASF As Their Framework Building Off Linux's CPUFreq + CPUIdle

Written by Michael Larabel in Arm on 7 July 2021 at 05:35 AM EDT. Add A Comment
Arm engineers are working on the Active Stats Framework (ASF) that is a new kernel framework for Linux effectively combining the current roles of CPUFreq and CPUIdle.

Active Stats Framework is responsible for dealing with statistics around CPU performance and the time residency spent at each performance state and tracking of all frequency transitions on a per-core basis.

The Active Stats Framework can then be used by their thermal governor and other areas of the kernel for making more informed decisions based on the current behavior of the hardware. Arm's ASF aims to provide more accurate data than what is currently achieved with their Intelligent Power Allocation (IPA) code in the kernel. Active Stats Framework is also a clean design compared to the separate CPUFreq and CPUIdle frameworks commonly used within the kernel but does rely on both existing frameworks as sources of the CPU frequency/power data.

Ultimately the hope is making use of ASF will provide more accurate power estimation, energy usage, and can be easily leveraged by other areas of the kernel for making more informed decisions. Those curious about the work being done by Arm on the Active Stats Framework for Linux can see this kernel patch series for all of the technical details.
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