powerlog

Power Consumption Logger for Linux. Logs CPU frequency, C-states, thermal state, battery level, and regulator status by reading from sysfs.

Requirements

• Linux with sysfs
• Root access may be needed for some sysfs paths (e.g. regulator)

Build

make

Usage

# Log to stdout every 5 seconds (default)
./powerlog

# Custom interval (bare number = seconds; suffix `s` or `ms`)
./powerlog -i 2
./powerlog -i 100ms

# Time-series: sample every 100ms for 10 seconds, then exit
./powerlog --interval 100ms --duration 10s

Timestamps include milliseconds so fast intervals stay ordered in logs and JSON.

# Log to file
./powerlog -o /var/log/powerlog.txt

# Combined
./powerlog -i 10 -o /var/log/powerlog.txt

# Brief aligned table for quick trends
./powerlog -b -i 1s
./powerlog --profile brief -i 1s

# Domain-only text (minimal within that domain)
./powerlog --profile thermal -i 2s
./powerlog --profile battery -i 2s

# Full text (same as -a)
./powerlog --profile full -i 2s

# CSV output for spreadsheets/plotting
./powerlog -c -i 1s -o powerlog.csv

# Alerts (stderr on threshold crossing; JSON includes an `alerts` array when active)
./powerlog -T 80 -B 15
./powerlog -j -o log.json -T 85

Options

Option	Description
-i, --interval TIME	Sample period: 5 or 5s = seconds, 100ms = milliseconds (default: 5s)
-d, --duration TIME	Stop after TIME (same format as interval); omit to run until interrupted
-o, --output FILE	Write log to file instead of stdout
-j, --json	Output in JSON format (pretty-printed)
-w, --with-cpuidle	Include C-state (cpuidle) data
-T, --alert-thermal C	Alert when any thermal zone reaches C °C
-B, --alert-battery PCT	Alert when battery is at or below PCT % while discharging
-h, --help	Show help
-a, --all	Text mode: print full details (all CPUs/thermal zones/regulators)
-b, --brief	Text mode: compact aligned table with one row per sample
-P, --profile NAME	Text layout preset: brief, thermal (thermal only, hottest line), battery (battery only), full (same as -a). Ignored with -j. If set, overrides -a/-b for layout; -c still selects CSV when present
-c, --csv	CSV mode: one row per sample with elapsed seconds (t_sec) + CPU/thermal/battery metrics and deltas; start_timestamp is printed once at top

Alerts

• Thermal (-T): Compares the hottest zone to the threshold. Messages go to stderr when the condition starts or clears (edge-triggered). With -j, each snapshot includes an alerts array listing current thermal/battery violations.
• Battery (-B): Only evaluated while the pack reports Discharging (or Unknown). Cleared when capacity rises above the threshold or status changes.

Logged Data

• CPU Frequency: Current frequency (MHz) and energy performance preference per CPU
• C-States (with -w): Idle state names, residency time (µs), and usage counts
• Thermal: Known sysfs types are renamed (e.g. x86_pkg_temp → cpu_package, iwlwifi_* → wifi). OEM sensors such as SEN1… are listed under Other sensors. Text lines append (Δ °C) vs the previous sample when available. JSON adds zone_delta_c (per thermal zone index), optional delta_c on other_sensors entries, and delta_mhz on each CPU in cpufreq.
• Battery: BAT* power supplies only (e.g. BAT0); HID accessories without capacity are omitted. Text/JSON only list entries with a readable capacity.
• Regulators: State (enabled/disabled) and voltage (µV) when available. The kernel regulator-dummy placeholder is omitted.

Install

sudo make install

License

MIT