A terminal system monitor for Apple Silicon Macs (M1 to M5). It shows CPU, GPU, memory, power, temperatures, fans, network, disk and a process table. Power and clock readings come from the SMC and IOReport and do not need root.
The screenshots are from siltop --demo, which plays a recorded 60-second session.
What it reads
| Reading | Source |
|---|---|
| CPU load per cluster (Efficiency, Performance, Super) | Mach host statistics |
| CPU and GPU clocks | IOReport residency |
| CPU, GPU, ANE and DRAM power | IOReport energy counters |
| System power, temperatures, fans | SMC |
| Memory, swap, memory pressure | sysctl, Mach VM statistics |
| Battery charge, health, cycles, adapter | IOKit power sources |
| Processes: CPU, footprint memory, energy, GPU, disk | proc_pid_rusage, sysctl kinfo |
Things a Mac does not have are left out: Airs have no fan readings, desktops have no battery.
Values macOS will not give to a normal user, such as other users' process memory, show as —.
On macOS 27 some IOReport power counters only update every few seconds. siltop shows the last
real reading with its age (≈ 4s) instead of reporting 0 W in between.
Compared with similar tools
| siltop | btop | macmon | asitop | |
|---|---|---|---|---|
| CPU / GPU / ANE / DRAM power | yes | no | yes | yes |
| Per-cluster clocks | yes | no | yes | yes |
| Temperatures and fans | yes | CPU temp | temps | no |
| Per-process energy and GPU | yes | no | no | no |
| Process tree, filter, signals | yes | yes | no | no |
Runs without sudo |
yes | yes | yes | no |
| Machine-readable output | JSON, NDJSON, Prometheus, CSV | no | JSON | no |
Measured on an M5 Pro at a 1 s interval, siltop uses about 1.3% of one CPU core, btop about 2.5% and macmon about 1.4%. Method and raw numbers: docs/research/12-self-cost.md.
Install
Requires macOS on Apple Silicon.
Homebrew:
brew install cloaky233/tap/siltop
Prebuilt binary, into ~/.local/bin:
mkdir -p ~/.local/bin && curl -fsSL https://github.com/CLoaKY233/siltop/releases/download/v1.2.1/siltop-v1.2.1-macos-arm64.tar.gz | tar -xz --strip-components 1 -C ~/.local/bin siltop-v1.2.1-macos-arm64/siltop
siltop update --yes updates a copy installed this way. Each
release also has a .zip and SHA-256 files.
The binary is not notarized, so a copy downloaded with a browser is blocked by macOS until
you run xattr -d com.apple.quarantine siltop.
From source (Rust 1.98 or newer):
cargo install --git https://github.com/CLoaKY233/siltop --tag v1.2.1 siltop --locked
Usage
siltop # the dashboard siltop --demo # a recorded session, no load needed siltop -i 1s --theme paper # sample every second, Paper theme siltop --surface glance --no-mouse # the compact view siltop --json | jq .cpu.clusters # one JSON sample (schema 1) siltop --json-stream --count 3 -i 500 # NDJSON, one line per interval siltop --diagnose # the verdict and its evidence siltop doctor # what this Mac exposes, for bug reports siltop line --style tmux # one status line: "cpu 12% gpu 3% 8.4W 51°C" siltop report week --json # energy by app, peak temperatures siltop agent install # alerts from a background LaunchAgent siltop record --duration 10m # record a session; `siltop replay` plays it siltop serve # Prometheus metrics on 127.0.0.1:9101 siltop bench --duration 5m # sustained CPU load test, reports throttling siltop fleet studio mini.local # several Macs side by side, over ssh siltop completions zsh # also bash and fish; `siltop man` prints the manual
In the dashboard, ? lists the keys, m opens the menu and s opens settings. The bottom
line shows a short verdict such as All normal or Busy: rustc using 9.1 cores.
The user guide covers every panel, the keys, settings, themes, alerts and scripting.
Configuration
Settings are in ~/.config/siltop/config.toml (or under $XDG_CONFIG_HOME). The file is
only written when you change a setting, and comments you add are kept. Environment variables:
| Variable | Effect |
|---|---|
SILTOP_THEME=<name> |
Theme. auto (the default) builds one from the terminal's colours. |
SILTOP_KEYS=htop|btop |
htop or btop key layout |
SILTOP_COLORS=truecolor|256|16|none |
Override the colour-depth guess |
SILTOP_ICONS=nerd |
Nerd Font icons in panel titles |
SILTOP_NO_UPDATE_CHECK=1 |
Never run the update check |
NO_COLOR=1 |
No colour |
Privacy
siltop sends nothing anywhere by default. The only network request is an update check
against the GitHub releases API, which is off until you turn it on; it runs /usr/bin/curl at
most once a day and sends only the version number in the User-Agent. siltop serve listens on
127.0.0.1 unless you pass --addr, and siltop fleet uses your own ssh. Crash reports are
written to disk and never sent.
FAQ
Why does my CPU read lower than Activity Monitor's? The CPU graph weights load by clock speed: a core busy at half its top clock counts as half busy. The cluster rows show the plain busy share and the clock separately.
Intel Macs, Linux? No. siltop uses Apple Silicon APIs. It compiles on other platforms but reads nothing there.
How it works
Four crates, dependencies pointing one way (core ← metrics, ui ← bin):
| Crate | Contents |
|---|---|
siltop-core |
Snapshot types, history store, config, verdicts |
siltop-metrics |
Collectors (SMC, IOReport, IOHID, Mach, sysctl) and the sampler |
siltop-ui |
Themes, braille graphs, layout, widgets |
siltop |
The binary: event loop, input, CLI, demo session |
A worker thread builds one Snapshot per interval and the UI draws it. Details are in
crates/ARCHITECTURE.md. Notes on the macOS APIs (SMC keys per chip,
reading IOReport energy without root, process data sources) are in
docs/research/.
Contributing
Bug reports are welcome, especially from chips or Mac models not covered yet. Please include
the output of siltop doctor. CONTRIBUTING.md covers building and tests.
License
MIT or Apache-2.0, at your option (LICENSE-MIT, LICENSE-APACHE). Copyright © 2026 Lay Sheth.