Sysmo

A terminal system monitor and software inventory for macOS, written in Rust.

Sysmo is a two-tab TUI built on ratatui:

• Monitor — live CPU, memory, swap, load, and process data, plus Apple-silicon hardware telemetry: CPU/GPU/ANE power draw, E-cluster and P-cluster frequencies, GPU utilization, temperatures, and fan speeds.
• Inventory — a scan of installed software: .app bundles, Homebrew formulae and casks, common command-line tools, and language toolchains, each with a detected version where available.

Requirements

• macOS
• A Rust toolchain with Cargo (edition 2024)

Hardware telemetry availability depends on the Mac and macOS version. Unsupported power, frequency, GPU, temperature, or fan readings are shown as unavailable while the rest of the monitor continues to work. No root or special entitlements are required.

Install

brew tap framicheli/sysmo
brew install sysmo

If Homebrew refuses to load the formula as an untrusted third-party tap, run brew trust framicheli/sysmo first, then retry brew install sysmo.

Or build from source:

cargo install --path .

Or build and run in place:

cargo run --release

To build the binary without running it:

cargo build --release
./target/release/sysmo

Configuration

There is no config file. One environment variable:

Variable	Effect
SYSMO_NO_FFI=1	Disable the hardware-specific collectors (IOReport, SMC, IOKit GPU) and show only the standard system metrics. Useful for troubleshooting or unsupported hardware.

SYSMO_NO_FFI=1 sysmo

Controls

Global

Key	Action
q, Esc	Quit
Tab, Shift-Tab, arrow left/right	Switch view
1, 2	Open Monitor or Inventory
p	Pause or resume metric updates
j/k, arrow down/up	Move selection

Monitor

Key	Action
c	Sort processes by CPU; press again to reverse
m	Sort processes by memory; press again to reverse
x	Kill the selected process

x sends the kill request immediately and does not ask for confirmation. Success or failure is reported in the status line.

Inventory

Key	Action
/	Filter by name (case-insensitive); Enter accepts, Esc clears
s	Cycle through source filters: All → App → Brew → Cask → Tool → Language
r	Rescan installed software (ignored while a scan is running)

While typing a filter, all other keys are captured as filter text.

What the inventory scans

Source	How it is found
App	.app bundles in /Applications, /System/Applications, and ~/Applications (one level of nesting, e.g. /Applications/Utilities); versions read from each bundle's Info.plist
Brew	Directories under <prefix>/Cellar for both /opt/homebrew (Apple silicon) and /usr/local (Intel)
Cask	Directories under <prefix>/Caskroom, same prefixes
Tool / Language	A fixed registry of well-known binaries (git, docker, gh, node, python3, go, rustc, java, …) located on PATH; each present binary is probed with its --version flag under a 2-second timeout

The scan runs on a background thread and streams results into the UI as they arrive, so the list fills immediately and version numbers appear as probes complete. The status line reports each category as it finishes and the total scan duration at the end.

Architecture

Three threads, connected by channels:

• UI thread (main.rs, app.rs, ui.rs) — event loop at a 1-second tick, event-driven rendering, all keyboard handling and state.

• Metrics thread (metrics/sysinfo_collector.rs) — samples CPU, memory, swap, load, and per-process data via the sysinfo crate once per second, merges in the latest hardware sample, and handles kill requests.

• FFI thread (metrics/ffi/) — polls Apple-silicon telemetry once per second through three independent collectors, each optional so a failure degrades gracefully:

  • ioreport.rs — power (CPU/GPU/ANE) and cluster frequencies via the private IOReport framework
  • smc.rs — temperatures and fan speeds via the SMC
  • gpu.rs — GPU utilization via IOKit

  The binding approach is derived from macmon (MIT).

Dependencies are deliberately minimal: ratatui + crossterm for the UI, sysinfo for standard metrics, core-foundation for the FFI, and plist for app bundle versions.

Test

cargo test

Unit tests cover key handling, sorting, filtering, and version parsing. A real-system inventory smoke test is ignored by default; run it with:

cargo test -- --ignored --nocapture