Bubo

A tiny macOS menu-bar monitor that tells you which app is making your Mac heavy.

_{Bubo is the genus of the eagle-owl: it watches all night and misses nothing.}

_{Light and dark. The panel follows your system appearance.}

A coloured load dot sits in your menu bar. Click it for the top apps eating CPU and memory, each with a one-click quit button, above a compact readout of the rest: GPU, fan, battery, temperatures, power, network, and disk.

Numbers match what the OS shows. Per-app memory is phys_footprint, the column Activity Monitor uses, and battery charge follows the figure macOS displays rather than the raw cell reading it drifts from.

_Demo

Why

Activity Monitor lives in a window you have to open and hunt through. Bubo puts the heaviest apps one click away in the menu bar, and quits the culprit without opening anything else. Two Swift files and a vendored sensor layer: no Electron, no background daemon.

Features

Section	What it shows
Menu bar	Green / yellow / red dot for overall load, plus live CPU % · MEM %
Top apps	The 8 heaviest processes, grouped per app, with a per-row quit button and a bar you can eyeball. Tap the PROC / CPU / MEM header to sort by that column (a ▾ marks the locked one; tap again to unlock)
CPU	Overall %, average temp, die hotspot, thermal pressure, and fan RPM against the fan's own floor and ceiling. Then a row per tier (efficiency, performance) carrying a bar for each core in it, that tier's usage, and its frequency
Memory	Used / total, split into app, wired, compressed, cached and free, with swap and DRAM read/write bandwidth
GPU	Usage, frequency, temperature, power
Battery	Charge %, charge/drain rate, adapter watts, cycles, health, capacity, cell temp
Power rails	CPU · GPU · ANE · DRAM · System, whichever your chip exposes, split by rail so you can see where the watts go
Network / Disk	Auto-scaled throughput (B/KB/MB per second)
Optimize	Purge disk cache, or quit every heavy app at once (with confirmation)

Right-click the menu-bar item for Keep Bubo in the menu bar, Check for Updates…, Activity Monitor, and Quit.

Sampling runs on a background queue and the panel is built at launch, so clicking it opens instantly. It drops straight down from the icon, flat against the menu bar, as tall as the screen allows.

Apple Silicon & Intel

Each Mac gets its own native build (no Rosetta); brew install and the download page pick the right one.

• Apple Silicon (M1–M5) — the full panel, every sensor listed above.
• Intel — the private power / temperature / fan / GPU / cluster / DRAM channels don't exist on Intel, so those panels hide and Bubo shows the essentials: CPU, memory, top apps, battery, network, and disk. Both builds follow your system appearance, light and dark.

_{On Intel the sensor-only panels drop away — shown here light and dark.}

Install

Homebrew

brew install fajarhide/tap/bubo

Homebrew installs the build matching your Mac (Apple Silicon or Intel) automatically. Bubo is ad-hoc signed, not notarized, so the cask clears the Gatekeeper quarantine flag on install and the app launches straight away.

Manual

1. From the latest release, download the .dmg for your Mac: Bubo-apple-silicon.dmg (M1/M2/M3…) or Bubo-intel.dmg.
2. Open it and drag Bubo into Applications.
3. First launch only: right-click Bubo.app → Open → Open. (Gatekeeper asks once, since it isn't notarized.)

Either way, right-click the menu-bar item → Keep Bubo in the menu bar so it's always there. It's a standard macOS login item you can switch off anytime (here or in System Settings) — no sudo, no kernel extension, no login daemon.

Build from source

Needs the Xcode command-line tools (swiftc and clang, via xcode-select --install).

./build.sh    # compile and install into ~/Applications (native arch)
./pack.sh     # build the shareable DMGs — one per arch

mk-app.sh <dest> is the shared compile step both scripts call.

Cutting a release

Releases are built and published by GitHub Actions, no local build needed:

git tag v1.0 && git push origin v1.0

Pushing a v* tag runs .github/workflows/release.yml, which builds both DMGs (Apple Silicon + Intel) on an Apple Silicon runner, attaches them to a new release, and bumps the Homebrew cask.

License

MIT. The vendored sensors/ code is MIT from MacMonitor; see sensors/LICENSE.MacMonitor.