cargo-goodtimes

Interactive compilation timing analyzer for Rust projects — visualizes the critical path of crate compilation as a Gantt chart.

Features

• Gantt chart of every crate's compilation timeline
• Critical path highlighting — see which dependency chain determines your total build time
• What-if analysis — modify dependency edges in the browser to explore hypothetical build graphs

Installation

cargo install cargo-goodtimes

Prebuilt frontend assets are included in the crate — no Bun or Node.js required.

Note: Modifying the frontend requires Bun.

Usage

# Analyze the project in the current directory
cargo goodtimes

# Analyze a specific project
cargo goodtimes --manifest-path /path/to/project

# Use release profile
cargo goodtimes --profile release

# Enable specific features
cargo goodtimes --features feat1,feat2

# Enable all features
cargo goodtimes --all-features

# Include third-party dependencies in the chart
cargo goodtimes --include-deps

# Don't open the browser automatically
cargo goodtimes --no-open

The tool will:

1. Clean workspace crates (external deps stay cached)
2. Run cargo check --timings
3. Parse the timing data and compute the critical path
4. Generate a self-contained HTML report and open it in your browser

Future improvements

• Machine-readable timings: Timing data is extracted by parsing the undocumented UNIT_DATA embedded in cargo's --timings HTML output, which may change between Rust versions. Cargo's --timings=json is currently nightly-only — once stabilized, this tool can switch to it for a more reliable data source.