[stevepike]

How does this work on the backend? Does it only trace method calls when an exception is thrown, or does it profile the call stack of every request?

Something I've been interested in is the performance impact of using https://docs.ruby-lang.org/en/3.2/Coverage.html to find unused code by profiling production. Particularly using that to figure out any gems that are never called in production. Seems like it could be made fast.

[aantix]

The idea is to turn it on for a given request when needed - via a parameter, feature flag, etc.

prepend_around_action :callstacking_setup, if: -> { params[:debug] == '1' }

Once the request completes, the instrumented methods are removed to remove the performance overhead.