Linux CPU Power

turbostat — CPU frequency, C-states, and power telemetry

turbostat reports CPU frequency, idle states (C-states), turbo boost behavior, and related power/performance counters. It’s especially useful on Intel CPUs (and works on many systems via kernel interfaces).

What turbostat is good for

Measuring CPU frequency and turbo behavior
Observing CPU idle states (C-states) and residency
Diagnosing power/performance issues on laptops and servers
Comparing tuning changes (governors, powertop, BIOS settings)

Tip: Run turbostat with sudo for best access to counters.

Install

On many distros, turbostat is part of the linux-tools package set. Package names vary by distro and kernel version.

# Debian/Ubuntu (common)
sudo apt install linux-tools-common linux-tools-$(uname -r)

# Fedora/RHEL (common)
sudo dnf install kernel-tools

# Arch (common)
sudo pacman -S linux-tools

10 Practical Examples

1) Run turbostat with defaults

sudo turbostat

Shows a live summary of CPU power/perf stats.

2) Update every 1 second

sudo turbostat --interval 1

Shorter interval helps spot spikes and turbo transitions.

3) Run for 10 samples then exit

sudo turbostat --interval 1 --num_iterations 10

Good for quick benchmarking or “before/after” comparisons.

4) Measure a command and exit when it finishes

sudo turbostat -- make -j$(nproc)

Runs the command while collecting telemetry, then prints totals.

5) Save output to a file (CSV-like)

sudo turbostat --interval 1 --num_iterations 60 > turbostat_60s.txt

Capture a 1-minute window for analysis.

6) Watch C-state residency during idle

sudo turbostat --interval 2

Let the system sit idle and observe deep C-state percentages.

7) Compare governor changes

# Example: change governor (if using cpufreq)
sudo cpupower frequency-set -g powersave
sudo turbostat --interval 1 --num_iterations 10

sudo cpupower frequency-set -g performance
sudo turbostat --interval 1 --num_iterations 10

See how frequency and residency differ.

8) Check package vs core behavior

sudo turbostat --interval 1

Look at “PkgWatt” and per-core frequencies to spot imbalances.

9) Reduce columns (focus on key stats)

sudo turbostat --Summary --interval 1

Show summary-focused view (options differ slightly by version).

10) Pair with powertop for tuning validation

sudo powertop --auto-tune
sudo turbostat --interval 1 --num_iterations 20

Apply tunings then confirm improved idle residency / reduced power.

Notes & Gotchas

Output columns vary by CPU model and tool version.
Some fields are Intel-specific; others work broadly through kernel telemetry.
BIOS/UEFI settings (C-states, Turbo, power limits) can dominate results.
Run on AC power vs battery can change behavior.
Use consistent conditions for before/after comparisons.