Observer

A dynamic CPU core manager for Linux systems that "intelligently" manages CPU cores based on system load and power state to help reduce power consumption. The application can be compiled on other systems (like macOS), but core management functionality is only active on Linux.

Features

• Dynamic core management (Linux-only):

  • Automatically adjusts active cores when running on battery vs AC power
  • Scales cores up/down based on real-time CPU load
  • Aware of heterogeneous architectures (P-cores vs E-cores) on supported systems, prioritizing P-cores for performance
  • Proper handling of CPU HyperThreading/SMT pairs
  • Smooth transitions between states
  • Always maintains system responsiveness with minimum core count

• Configurable settings:

  • Battery mode core percentage (battery_core_percentage)
  • AC power mode core percentage (ac_core_percentage)
  • CPU load thresholds for scaling (separate for battery and AC)
  • Minimum core count
  • Check intervals
  • Core transition delays

• System integration:

  • Runs as a systemd service
  • Graceful shutdown handling
  • Proper logging with different verbosity levels
  • Configuration file in TOML format

Installation

Quick Install

curl -sL "https://github.com/voioo/observer/releases/latest/download/observer-linux-amd64.tar.gz" | sudo bash -c 'tar xz -C /tmp && bash /tmp/install.sh'

Uninstall

curl -sL "https://raw.githubusercontent.com/voioo/observer/main/uninstall.sh" | sudo bash

Arch Linux (AUR)

yay -S observer

Manual Installation

1. Download the appropriate archive for your architecture from the releases page
2. Extract and install:

tar xzf observer-linux-*.tar.gz
sudo chmod +x install.sh && sudo ./install.sh

Configuration

The configuration file is located at /etc/observer/config.toml:

# Percentage of cores to enable when on battery (1-100)
battery_core_percentage = 50

# Percentage of cores to enable when on AC power (1-100)
ac_core_percentage = 100

# Delay in milliseconds between enabling/disabling each core
transition_delay_ms = 500

# How often to check power state and CPU load (in seconds)
check_interval_sec = 5

# CPU load threshold percentage to trigger core count adjustment (when on battery)
cpu_load_threshold = 75.0

# CPU load threshold percentage to trigger core count adjustment (when on AC)
ac_cpu_load_threshold = 90.0

# Minimum number of cores to keep enabled
min_cores = 2

Usage

Observer runs as a systemd service. Control it using:

# Start the service
sudo systemctl start observer

# Enable on boot
sudo systemctl enable observer

# Check status
sudo systemctl status observer

# View logs
sudo journalctl -u observer -f

Building from Source

Prerequisites

• Rust toolchain (1.70.0 or newer)
• Cargo

Build Steps

# Clone the repository
git clone https://github.com/voioo/observer.git
cd observer

# Build
cargo build --release

# Install (optional)
sudo chmod +x install.sh && sudo ./install.sh

Platform Support

• Linux (x86_64, aarch64, armv7): Full feature support, including dynamic core management and P/E core awareness (where applicable).
• macOS / Other non-Linux: Compiles and runs, but core management features are disabled. The application will log warnings indicating this and operate with all cores available to the OS.

Architecture Support

• x86_64 (AMD64) - Full support
• aarch64 (ARM64) - Full support
• armv7 (32-bit ARM) - Basic support
  • Note: Some ARM systems might have limited CPU core control capabilities
  • Performance might vary based on specific hardware

Architecture-Specific Considerations

• x86_64: Full support for all features including HyperThreading detection
• aarch64: Full support, optimized for modern ARM64 processors
• armv7: Basic support, some features might be limited by hardware capabilities

Contributing

Contributions are welcome! Check the contributing guide and feel free to submit a PR.

License

This project is licensed under the 0BSD License.

Acknowledgments

• Inspired by various power management tools and CPU governors
• Thanks to the Rust community for excellent crates

Installation

Download the appropriate archive for your architecture:

• AMD64 (x86_64): observer-linux-amd64.tar.gz
• ARM64 (aarch64): observer-linux-arm64.tar.gz
• ARMv7 (32-bit): observer-linux-armv7.tar.gz