I tested the ruby agent 3.7.1.188 of New Relic but I don't understand the purpose of the ruby-prof gem. When I go to http://localhost:3000/newrelic, on the right side is a message that says that I can use the ruby-prof gem to display profiles. So I installed ruby-prof gem and clicked on "Start profiling" then clicked around my site and finally clicked on "stop profiling". I can now click on the URLs to see how long some action lasts. But I get the same statistics without ruby-prof. So where is the exact purpose of ruby-prof regarding the New Relic agent?
Ruby Version: 2.0.0 Rails version: 4.0.0
The purpose of using the ruby-prof gem from within the Ruby agent's developer mode feature is to be able to capture and display execution profiles that instrument each method call that's made while servicing a request. Unfortunately, integration with ruby-prof is one of the older corners of the newrelic_rpm code base, and as such has fallen into a bit of disrepair. That said, it's useful for solving certain kinds of problems, so we're making an effort to revive it. New Relic has just released version 3.7.2 of the newrelic_rpm gem, which should fix ruby-prof integration for Rails 3 and Sinatra applications, and we're planning to fix it for Rails 4 in an upcoming release. If you're interested, you can watch for the next beta release of the newrelic_rpm gem, which should include a fix for ruby-prof usage in Rails 4.