CPU Monitor

A terminal-based CPU monitoring tool written in Go. Features real-time CPU usage visualization with per-core monitoring, memory tracking, and system metrics.

Features

• 🚀 Real-time CPU monitoring with sub-second refresh rates
• 📊 Per-core usage tracking with multi-column layout for many-core systems
• 📈 60-second history graph with color-coded usage levels
• 💾 Memory usage monitoring with visual progress bars
• ⚡ Low overhead - optimized to use only 1-2% CPU
• 🎯 Interactive controls - pause, reset, and help system
• 🖥️ Cross-platform - works on macOS and Linux

Installation

Build from Source

Prerequisites

• Go 1.21 or higher
• Git

Quick Install

# Clone the repository
git clone https://github.com/yourusername/cpu-monitor.git
cd cpu-monitor

# Build and install
go build -o cpu-monitor ./cmd/cpu-monitor

# Optional: Move to PATH
sudo mv cpu-monitor /usr/local/bin/

Building for Different Platforms

macOS

Intel (amd64)

GOOS=darwin GOARCH=amd64 go build -o cpu-monitor-darwin-amd64 ./cmd/cpu-monitor

Apple Silicon (arm64)

GOOS=darwin GOARCH=arm64 go build -o cpu-monitor-darwin-arm64 ./cmd/cpu-monitor

Linux

Intel/AMD (amd64)

GOOS=linux GOARCH=amd64 go build -o cpu-monitor-linux-amd64 ./cmd/cpu-monitor

ARM64

GOOS=linux GOARCH=arm64 go build -o cpu-monitor-linux-arm64 ./cmd/cpu-monitor

Usage

Basic Usage

# Run with default settings
cpu-monitor

# Show help
cpu-monitor -help

Command Line Options

Flag	Description	Default
-refresh ms	Set refresh rate in milliseconds (100-5000)	500
-history n	Number of history points to keep	120
-avg n	Moving average window size	10
-help	Show command line help	-

Examples

# Update every second
cpu-monitor -refresh 1000

# Reduce history buffer for lower memory usage
cpu-monitor -history 60 -avg 5

# Fast refresh for detailed monitoring
cpu-monitor -refresh 100

Keyboard Controls

Key	Action
h	Toggle help screen
q, Ctrl+C	Quit application
r	Reset CPU history
p	Pause/unpause monitoring

Display Sections

Main View

• Total CPU: Overall system CPU usage percentage
• Moving Average: 10-sample moving average of CPU usage
• Core Bars: Individual CPU core usage with htop-style bars
• CPU History: 60-second vertical bar graph showing usage over time
• Memory: System RAM usage with visual progress bar
• System Info: Load average, process count, and uptime

Color Indicators

• 🟢 Green (0-30%): Low usage
• 🔵 Blue (30-50%): Light usage
• 🟡 Yellow (50-70%): Moderate usage
• 🟠 Orange (70-90%): High usage
• 🔴 Red (90-100%): Critical usage

Performance

CPU Monitor is highly optimized for minimal system impact:

• CPU Usage: ~1-2% on modern systems
• Memory: ~15-25 MB RAM
• Update Rate: Configurable from 100ms to 5 seconds

Optimization Features

• Cached static system information
• Throttled expensive operations (temperature, process count)
• Pre-rendered UI styles
• Efficient string building
• Proper CPU sampling intervals

System Requirements

Minimum Requirements

• OS: macOS 10.15+ or Linux kernel 3.0+
• Terminal: Any terminal with 256-color support
• Width: Minimum 80 columns
• Height: Minimum 24 rows

Recommended

• Terminal: iTerm2, Alacritty, or Kitty
• Font: Monospace font with Unicode support
• Size: 120+ columns for optimal display

Technical Details

Dependencies

• Bubble Tea - Terminal UI framework
• Lip Gloss - Style definitions
• gopsutil - System information gathering

Project Structure

cpu-monitor/
├── cmd/
│   └── cpu-monitor/    # Application entry point
├── internal/
│   ├── config/         # Configuration and constants
│   ├── metrics/        # System metrics collection
│   └── ui/             # Terminal UI components
├── go.mod              # Go module definition
└── go.sum              # Dependency checksums

Troubleshooting

High CPU Usage

If CPU Monitor itself is using too much CPU:

1. Increase the refresh rate: cpu-monitor -refresh 1000
2. Reduce history size: cpu-monitor -history 60
3. Check for other system monitoring tools running simultaneously

Temperature Not Showing

• macOS: Temperature sensors may require additional permissions or tools
• Linux: Ensure lm-sensors is installed: sudo apt-get install lm-sensors

Display Issues

• Ensure your terminal supports 256 colors: echo $TERM
• Try resizing your terminal window
• Use a monospace font with Unicode support

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Built with Bubble Tea by Charm
• System metrics via gopsutil
• Inspired by htop, btop, and other terminal monitoring tools

Author

Created with ❤️ for the terminal by Ed Engelking as an experiment with Claude Code.