Profile a rails controller action


What is the best way to profile a controller action in Ruby on Rails. Currently I am using the brute-force method of throwing in puts calls between what I think will be a bottleneck. But that feels really, really dirty. There has got to be a better way.


This works in Rails 4.2.6: Rails.logger)
    o.extend ActiveSupport::Benchmarkable
    o.benchmark 'name' do
      # ... your code ...
By : P.S.V.R

I picked up this technique a while back and have found it quite handy.

When it's in place, you can add ?profile=true to any URL that hits a controller. Your action will run as usual, but instead of delivering the rendered page to the browser, it'll send a detailed, nicely formatted ruby-prof page that shows where your action spent its time.

First, add ruby-prof to your Gemfile, probably in the development group:

group :development do
    gem "ruby-prof"

Then add an around filter to your ApplicationController:

around_filter :profile if Rails.env == 'development'

def profile
  if params[:profile] && result = RubyProf.profile { yield }

    out = out, :min_percent => 0
    self.response_body = out.string


Reading the ruby-prof output is a bit of an art, but I'll leave that as an exercise.

Additional note by ScottJShea: If you want to change the measurement type place this:

RubyProf.measure_mode = RubyProf::GC_TIME #example

Before the if in the profile method of the application controller. You can find a list of the available measurements at the ruby-prof page. As of this writing the memory and allocations data streams seem to be corrupted (see defect).

By : Rob Davis

You might want to give the FiveRuns TuneUp service a try, as it's really rather impressive. Disclaimer: I'm not associated with FiveRuns in any way, I've just tried this service out.

TuneUp is a free service whereby you download a plugin and when you run your application it injects a panel at the top of the screen that can be expanded to display detailed performance metrics.

It gives you some nice graphs, including one that shows what proportion of time is spent in the Model, View and Controller. You can even drill right down to see the individual SQL queries that ActiveRecord is executing if you need to and it can show you the underlying database schema with another click.

Finally, you can optionally upload your profiling data to the FiveRuns site for community performance analysis and advice.

This video can help you solving your question :)
By: admin