rbspy

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.