schedutil

Schedutil is a Linux kernel CPU frequency governor in the cpufreq framework. It is designed to adjust the processor’s frequency dynamically based on the scheduler’s utilization metrics, offering a lightweight and responsive alternative to traditional load-based governors.

How it works

Schedutil relies on the Linux scheduler’s utilization data to infer workload intensity on each CPU. By interpreting per-CPU util measures from the scheduler, it selects target frequencies from the CPU’s available operating performance points (OPPs). When util increases beyond certain thresholds, the governor raises the frequency; when util decreases, it lowers the frequency. This approach aims to provide faster, smoother adjustments with reduced overhead and less frequency jitter compared with some older schemes.

Implementation and usage

Schedutil is implemented as a per-CPU Governor within the cpufreq subsystem. It is available on most modern architectures that expose a cpufreq interface, including x86 and ARM. Users can typically enable schedutil by selecting it as the scaling governor for each CPU, and many systems may adopt it as a default or recommended option for contemporary kernels. The governor exposes tunable parameters via sysfs to control responsiveness and ramp rates, allowing administrators to tailor behavior to workloads and power/performance goals.

Comparison and context

Compared with other governors such as ondemand or performance, schedutil seeks to align frequency changes with the scheduler’s view of actual work, aiming for better power efficiency and reduced frequency oscillations. It is part of the broader Linux cpufreq ecosystem and is commonly used on systems where the balance between performance and energy use is a priority.

See also: CPU frequency scaling, cpufreq, Linux kernel governors, scheduler utilization.