smt-toggle

A GUI application with system tray integration for toggling CPU SMT (Simultaneous Multi-Threading / Hyperthreading) on Linux.

Features

• Toggle SMT on/off via a simple GUI toggle switch
• System tray icon - closing the window minimizes to tray
• Automatic privilege escalation via pkexec when needed
• Displays current SMT status (on, off, forceoff, notsupported)

How it Works

The application reads and writes to /sys/devices/system/cpu/smt/control to control SMT. If direct write fails (no root permissions), it uses pkexec tee to prompt for authentication.

System Requirements

• Linux (uses Linux sysfs interface)
• GTK3 development libraries
• libappindicator3 or libayatana-appindicator3 (for system tray)
• libxdo (required by tray-icon crate)
• pkexec (polkit) for privilege escalation
• Rust toolchain (edition 2024)

Fedora/RHEL

sudo dnf install gtk3-devel libappindicator-gtk3-devel libxdo-devel

Ubuntu/Debian

sudo apt install libgtk-3-dev libayatana-appindicator3-dev libxdo-dev

Arch

sudo pacman -S gtk3 libappindicator-gtk3 xdotool

Building

cargo build --release

The binary will be at target/release/smt-toggle.

Usage

./target/release/smt-toggle

The application starts with a window showing the current SMT status. Use the toggle to enable/disable SMT. Closing the window hides it to the system tray - use the tray icon menu to show the window again or quit the application.

Dependencies

• iced 0.14 - GUI framework
• tray-icon 0.21.3 - System tray
• gtk 0.18 - GTK bindings (for tray support)
• tokio 1 - Async runtime

License

AGPL-3.0