Rails 3 plugin which surfaces slow code paths in your Rails application by integrating with the new Notifications API in Rails 3 with your system Growl (OSX) or libnotify (Linux) notification service. By default, any activity which takes longer than one second, will generate a growl alert, with the description of the action, time taken, and other meta data. A preview in action:

slowgrowl notification

Integrating with Rails 3

# in your Gemfile
group :development do
    gem 'slowgrowl'

That's it.

Optional Configuration for SlowGrowl

# in your config/environments/development.rb
config.slowgrowl.warn = 1000    # growl any action which takes > 1000ms (1s)
config.slowgrowl.sticky = true  # make really slow (2x warn) alerts sticky