Have you ever wanted to know what functions your Ruby program is calling? rbspy can tell you!

rbspy lets you profile Ruby processes that are already running. You give it a PID, and it starts profiling! It's a sampling profiler, which means it's low overhead and safe to run in production.

Quick start

If you're on macOS, install rbspy with Homebrew:

brew install rbspy

If you have a working Rust toolchain (1.56 or newer), you can install with cargo:

cargo install rbspy

Otherwise, check out the installing section to get rbspy running on your computer.

Profiling a Ruby program

If your program is already running, get its PID and profile it like this:

rbspy record --pid $PID

You can also use rbspy to profile a Ruby script, like this. It works both with and without bundle exec.

rbspy record -- bundle exec ruby my-script.rb

Here's what running rbspy record on a Rubocop process looks like. You'll see a live summary of what the top functions being run are, and it also saves the raw data + a flamegraph for more in depth analysis.