💻🔋 macpow

May 11, 2026 · View on GitHub

Real-time power consumption monitor for Apple Silicon Macs (M1–M5+).

macpow screenshot

macpow reads directly from macOS hardware interfaces — IOReport, SMC, IORegistry, CoreAudio, and Mach/kernel APIs — to show per-component power draw, temperatures, frequencies, CPU utilization, and per-process energy attribution. No sudo required.

Legend

Symbol	Meaning
`0.123 W`	Measured power (direct hardware reading)
`≈0.123 W`	Estimated power (model-based calculation)
`≤0.123 W`	Upper-bound power estimate
`▸`	Pinned resource (sparkline chart visible)
`▓▓▓░░░░░░░`	CPU core utilization bar (filled = busy)
`37°C`	Fresh temperature reading
`~37°C`	Stale temperature (sensor read failed, showing last known value)
`pending…`	Data source still initializing
`[dead]`	Process has exited (energy total preserved)
Bold white	Section headers and measured values
Green	Low power (< 1W) or info-only rows
Yellow	Moderate power (1–5W)
Orange	High power (5–10W)
Red	Very high power (> 10W)
Gray	Dimmed/inactive items

Features

SoC breakdown — CPU (E/P cores with per-core power, utilization bars, temperatures), GPU, ANE, DRAM, GPU SRAM, Media Engine, Camera (ISP), Fabric — all from IOReport Energy Model
CPU utilization — per-core usage % with visual bars from Mach host_processor_info
Real frequencies — CPU and GPU MHz from DVFS voltage-states tables, not percentages
Temperatures — per-component and per-core from SMC sensors (CPU, GPU, ANE, DRAM, SSD, Battery); universal bank-based key mapping for all Apple Silicon generations (M1–M5+, including Ultra dual-die); stale value caching with ~ indicator when sensors temporarily read invalid
Memory — used/total GB via host_statistics64 Mach API
Display — brightness, panel class (SDR/HDR/XDR), refresh rate / ProMotion, live HDR-active indicator from AppleARMBacklight IOReport DPB factor, plus IOReport SoC display controller and external display power via DISPEXT
Keyboard — backlight brightness and estimated power via IORegistry PWM
Battery — voltage, amperage, charge %, time remaining, temperature, drain/charge rate
SSD — model, interconnect (Apple Fabric/PCIe), power estimation from IORegistry disk counters
Peripherals — Thunderbolt/PCIe (IOReport measured), Ethernet (link speed, per-interface traffic), WiFi (signal/mode/channel, per-interface traffic), Bluetooth devices with battery levels, USB devices (speed/power/I/O counters)
Per-process energy — dynamically-sized top processes by session energy (from proc_pid_rusage), with per-process disk I/O rates, network traffic (via nettop), RAM footprint, dead process detection
Fans — RPM and cubic power model per fan
Collapsible tree — fold/unfold with arrows, +/- for all
Sparkline charts — pin any resource with Space, inline 1-line history column at wide terminals
Time-based SMA — toggle 0s/5s/10s smoothing window
Latency control — toggle UI refresh rate: 500ms / 2s / 5s
Mouse support — click to select rows
JSON mode — pipe structured data for scripts and dashboards
No sudo — runs entirely with user-level permissions

Install

With cargo

cargo install macpow

From source

git clone https://github.com/k06a/macpow.git
cd macpow
cargo build --release
./target/release/macpow

Homebrew

brew tap k06a/tap
brew install macpow

With pixi (conda-forge)

pixi global install macpow
# execute without installing
pixi exec macpow

Usage

macpow                    # TUI mode (default)
macpow --json             # JSON output to stdout
macpow --interval 500     # Set sampling interval in ms (default: 250)
macpow --dump             # Dump IOReport channel names (diagnostics)
macpow --dump-smc         # Dump every SMC key with type and value (diagnostics)

Keybindings

Key	Action
`q` / `Esc`	Quit
`Up` / `Down` / `j` / `k`	Move cursor
`Left` / `Right` / `h`	Collapse / expand tree node
`+` / `=`	Expand all nodes
`-`	Collapse all nodes
`Space`	Pin/unpin resource chart
`a`	Cycle SMA window: 0s / 5s / 10s
`l`	Cycle refresh interval: 250ms / 500ms / 1s / 2s
`r`	Reset all totals and min/max
`PgUp` / `PgDn`	Scroll by 10 rows
`Home`	Jump to top
Mouse click	Select row

All letter keys work on any keyboard layout (QWERTY, Russian, Dvorak, etc).

Architecture

Each data source runs in its own thread, updating shared metrics at its own pace. The TUI renders at the configured interval without blocking on slow sources.

+------------------+---------------------------------------------+
| Data source      | What it provides                            |
+------------------+---------------------------------------------+
| IOReport         | SoC power (Energy Model),                   |
|                  | CPU/GPU frequencies (DVFS residency)        |
| SMC              | System power (PSTR), display backlight     |
|                  | (PBwo on M5/Neo, PDBR on M1-M4),         |
|                  | adapter (PDTR), WiFi (wiPm), temps, fans   |
| IORegistry       | Battery, display brightness, keyboard PWM,  |
|                  | USB devices, SSD model, disk I/O counters   |
| CoreAudio        | Volume level, mute state                    |
| Mach API         | Per-CPU utilization ticks, memory stats      |
| proc_pid_rusage  | Per-process billed energy                   |
| getifaddrs       | Network traffic byte counters               |
| CoreWLAN/pmset   | WiFi info, Bluetooth devices                |
| IOPMAssertions   | Power assertions, audio playback detection  |
+------------------+---------------------------------------------+

Power measurements vs estimates

Component	Source	Method
CPU, GPU, ANE, DRAM	IOReport	Direct energy measurement (mJ/uJ/nJ deltas)
Media Engine, Camera (ISP)	IOReport	Direct energy measurement (AVE + MSR, ISP)
Fabric (AMCC, DCS, FAB, AFR)	IOReport	Direct energy measurement
Thunderbolt/PCIe	IOReport	Direct energy measurement (PCIe ports + controllers)
Display backlight	SMC PBwo (M5 Pro/Max/Neo, A18) / PDBR (M1-M4 XDR)	Direct power rail measurement
Display controller	IOReport DISP/DISPEXT	Direct energy measurement (SoC + external)
Power adapter	SMC PDTR	Direct power delivery measurement
System total	SMC PSTR	Direct power rail measurement
Battery	IORegistry	V * I calculation
Per-process	Kernel	`ri_billed_energy` from rusage_info_v4
Per-process disk I/O	Kernel	`ri_diskio_bytesread/written` from rusage_info_v4
Per-process memory	Kernel	`ri_phys_footprint` from rusage_info_v4
Per-process network	nettop	Cumulative bytes per process (~18ms subprocess)
CPU utilization	Mach API	`host_processor_info` tick deltas
Memory	Mach API	`host_statistics64` (active + inactive + wired + compressor pages)
Keyboard	IORegistry PWM	Duty cycle * 0.5W max
Fans	SMC RPM	Cubic model: (RPM/RPM_max)^3 * 1W
Audio	CoreAudio + IOPMAssertions	Idle 0.05W + volume^2 * 1W
WiFi	SMC wiPm	Direct power measurement
Bluetooth	pmset	Fixed per device type (0.01-0.05W)
SSD	IORegistry counters	I/O utilization: 0.03-2.5W
Ethernet	getifaddrs	Link detection, speed, per-interface traffic (data only)
Network	getifaddrs	Per-interface byte counters for Ethernet and WiFi
USB	IORegistry PowerOutDetails	Per-port power measurement (Watts/PDPowermW)

IOReport channel naming (multi-die support)

IOReport channel names vary between single-die and multi-die (Ultra) chips. The parser handles both generically:

Single-die (M1/M2/M3/M4 base/Pro/Max):
  CPU Stats:    ECPU0, PCPU10             ← digit suffix
  Energy Model: EACC_CPU0, PACC0_CPU5     ← _CPU suffix
  Blocks:       ISP, DRAM, ANE, DISP      ← bare names

Multi-die (M1/M2/M3 Ultra):
  CPU Stats:    DIE_0_ECPU_CPU0, DIE_1_PCPU1_CPU3   ← DIE_N_ prefix + _CPU suffix
  Energy Model: DIE_0_EACC_CPU0, DIE_1_PACC1_CPU3   ← DIE_N_ prefix + _CPU suffix
  Blocks:       ISP0_0, DRAM0_1, ANE0_0              ← per-die suffix

Two design rules keep this forward-compatible with future chips:

strip_die_prefix generically removes DIE_{N}_ so downstream parsers always see the same base format
starts_with matching for block power handles any suffix Apple may add (e.g. ISP matches ISP, ISP0_0, ISP0_1, etc.)

If a new chip isn't detected correctly, run macpow --dump to see the raw IOReport channel names.

Requirements

macOS 12+ (Monterey or later)
Apple Silicon (M1, M2, M3, M4, M5 — any variant)
Rust 1.70+

Release checklist

Toolchain pinning. The repo ships a rust-toolchain.toml that pins stable, matching dtolnay/rust-toolchain@stable in CI. Run rustup update stable before each release so local clippy/fmt see the same lints CI does — newly-promoted clippy lints have caused CI failures after cargo publish already uploaded the broken version (immutable), so this step is non-optional.

# 0. Make sure the toolchain matches CI exactly
rustup update stable
rustc --version    # note the version; CI is on the same `stable`

# 1. Bump version
vim Cargo.toml                        # update version = "X.Y.Z"

# 2. Build, lint, test — must all pass before the version bump commit
cargo fmt --check                     # formatting clean
# Clippy: copy this command verbatim from .github/workflows/ci.yml.
# CI does NOT pass --all-targets, so neither do we — adding it pulls in
# benches/examples that CI ignores and would block the release.
cargo clippy -- -D warnings -A clippy::field_reassign_with_default -A clippy::manual_c_str_literals -A clippy::manual_clamp -A clippy::manual_range_contains -A clippy::missing_safety_doc -A clippy::needless_range_loop
cargo test                            # all tests pass
cargo build --release                 # final binary build

# 3. Dry-run the publish so any cargo-side issues show up before tagging
cargo publish --dry-run

# 4. Update Homebrew badge in README.md
#    Change: homebrew-vX.Y.Z in the badge URL

# 5. Commit, tag, push
git add -A
git commit -m "Bump version to X.Y.Z"
git tag vX.Y.Z
git push origin main --tags
# CI will auto-create GitHub Release with binary

# 6. Publish to crates.io  (immutable — only after CI is green!)
cargo publish

# 7. Update Homebrew tap (via PR to trigger bottle building)
curl -sL https://github.com/k06a/macpow/archive/refs/tags/vX.Y.Z.tar.gz | shasum -a 256
# Update url + sha256 in homebrew-tap/Formula/macpow.rb
cd ../homebrew-tap
git checkout main && git pull
git checkout -b update-macpow-X.Y.Z
# edit Formula/macpow.rb (url + sha256 only — bottle block is auto-rewritten)
git commit -am "Update macpow to X.Y.Z"
git push origin update-macpow-X.Y.Z
# Create PR, wait for CI to build bottles, then add label "pr-pull"
# publish.yml will upload bottles and merge the PR

# 8. Update conda-forge feedstock
cd ../macpow-feedstock
git checkout main && git pull origin main
git checkout -b bump-X.Y.Z
# edit recipe/recipe.yaml: bump `version:` and update `sha256:` (same value as step 7)
git commit -am "macpow vX.Y.Z"
git push fork bump-X.Y.Z   # fork remote, since origin is conda-forge upstream
# Open PR against conda-forge/macpow-feedstock from your fork branch

If CI fails AFTER you ran cargo publish (step 6), that crates.io version is immutable. Yank it (cargo yank --version X.Y.Z) and bump the patch number — don't try to force-push the tag.

Contributing

Before submitting a PR, please run:

cargo fmt --check          # code formatting
# Clippy: must match CI (see .github/workflows/ci.yml)
cargo clippy -- -D warnings -A clippy::field_reassign_with_default -A clippy::manual_c_str_literals -A clippy::manual_clamp -A clippy::manual_range_contains -A clippy::missing_safety_doc -A clippy::needless_range_loop
cargo test                 # unit + integration tests
cargo build --release      # final build check

All four must pass with zero errors. Clippy needs the flags above so local runs match CI; without them, stable Clippy may report project-wide warnings that CI intentionally allows (FFI / Objective-C style).

Collecting diagnostics

If per-core temperatures are missing or incorrect on your Mac, please open an issue with:

macpow --dump > dump.txt                       # IOReport channel names
macpow --dump-smc > smc.txt                    # all SMC keys (incl. power rails)
macpow --json > metrics.json                   # full metrics (Ctrl+C after ~15s)
system_profiler SPHardwareDataType | head -10   # chip model

This helps add support for new Apple Silicon variants.

License

MIT