FreeBSD 12 – Common Problem 018 – powerd Is Not Scaling CPU Frequency

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

CPU remains at low or fixed frequency, reducing performance or efficiency.

Environment & Reproduction

Seen after BIOS updates or cloned system images lacking powerd settings.

Root Cause Analysis

`powerd` disabled, unsupported governor mode, or missing ACPI cpufreq support.

Quick Triage

Inspect current frequency controls.

service powerd status
sysctl dev.cpu.0.freq
sysctl dev.cpu.0.freq_levels

Step-by-Step Diagnosis

Stress CPU and watch frequency transitions.

yes > /dev/null &
sysctl dev.cpu.0.freq
killall yes

Solution – Primary Fix

Enable adaptive powerd profile and restart service.

sysrc powerd_enable='YES'
sysrc powerd_flags='-a hiadaptive -b adaptive'
service powerd restart

Solution – Alternative Approaches

Set fixed performance profile for latency-critical workloads where thermal budget allows.

Verification & Acceptance Criteria

Frequency scales up under load and down at idle with expected thermal behavior.

Rollback Plan

Revert `powerd_flags` and restart service if instability or throttling anomalies occur.

Prevention & Hardening

Include power profile checks after firmware upgrades and kernel updates.

Related Errors & Cross-Refs

No available `freq_levels`, static low frequency, thermal throttling warnings.

Related tutorial: View the step-by-step tutorial for freebsd-12.

View all freebsd-12 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

`powerd(8)`, `acpi(4)`, FreeBSD power management docs.