ActiveProfiling¶ ↑

ActiveProfiling is a gem I’ve slapped together over the years to help with profiling Rails applications.

Profiler ActionController Filters¶ ↑

action_profiler¶ ↑

This filter wraps up the functionality of RubyProf for each action and can be used to spit out the results to stdout, your log file or to files in the Rails.root/log/profiling directory.

Options and their defaults for action_profiler are listed in ActiveProfiling::Railtie::DEFAULT_PROFILER_OPTIONS, but the gist of it is that you can basically use any of RubyProf’s various options and control where the output is directed. For some the :call_tree output type, results are written to individual files in Rails.root/log/profiling, while for all other output types the results are written to the Rails log. You can of course redirect all logging to files if you prefer, or to the standard output.

To enable this filter, add the following to your application configuration:

config.active_profiling.profiler.enabled = true

Additional configuration options can be found in the documentation for ActiveProfiling::Railtie.

action_gc_statistics¶ ↑

This filter wraps up the functionality of either GC::Profiler in Ruby 1.9+ or the GC statistics patches available for 1.8.7 if installed, either through Ruby Enterprise Edition or by patching your own Ruby. When enabled, information on the Ruby garbage collector will be written to the Rails log at the end of each action response. Options for controlling how the information is collected and logged can be found in ActiveProfiling::Railtie::DEFAULT_GC_STATISTICS_OPTIONS.

Note that the output for Ruby 1.9+ is a bit different from REE or a patched Ruby due to the manner in which they collect and report on GC statistics. In the REE patches you can access a number of options that aren’t currently available in GC::Profiler. I’ve tried to make some sensible output for REE, but there are going to be differences based solely on the manner in which the statistics are collected.

To enable this filter, add the following to your application configuration:

config.active_profiling.gc_statistics.enabled = true

Additional configuration options can be found in the documentation for ActiveProfiling::Railtie.

Profiling Blocks¶ ↑

You can also profile individual blocks of code by using the ActiveProfiling.ruby_profiler and ActiveProfiling.gc_statistics methods or by including the ActiveProfiling::RubyProfiler or ActiveProfiling::GCStatistics modules and using the methods in your own classes and modules. In both cases, these methods take the same options as found in the ActionController filters minus the :enabled option.

# Will spit out the GC statistics if GC is run, same as with the action
# filter.
ActiveProfiling.gc_statistics do
  # ...
end

# Wraps the block in a RubyProf session and logs the results accordingly.
ActiveProfiling.ruby_profiler(options) do
  # ...
end

Extended ActiveRecord Logging¶ ↑

The database can often be a performance hotspot, and tracking down where and why some queries are occuring in your application can be a pain. ActiveProfiling includes an extended query logger that can be configured to log backtraces for SQL queries that can help you track down where unexpected queries are occuring in your code.

To enable extended logging, add the following to your application configuration:

config.active_profiling.active_record.backtrace_logger.enabled = true

Additional configuration options can be found in the documentation for ActiveProfiling::Railtie.

Using In A Rails Project¶ ↑

Profiling should be performed in a production environment, as profiling in development really isn’t reflective of how your application is actually going to be running in the Real World. At the same time, you don’t necessarily want to clutter up your application settings and Gemfile with unnecessary code and have to worry about accidentally committing profiling settings to your source code repository and the like.

A semi-neat trick to try is to set up a file for local application settings thusly:

First, add the following to your application.rb. You generally want this near the end of the file.

if File.exists?("#{Rails.root}/config/application_local.rb")
  require "#{Rails.root}/config/application_local.rb"
end

Add an entry for application_local.rb to your .gitignore file or otherwise ignore it with your SCM.

In application_local.rb, you can set up additional application settings like so:

# You can now flip this line on and off to enable or disable
# ActiveProfiling.
Bundler.require(:profiling, Rails.env) if defined?(Bundler)

module FooBarApp
  class Application < Rails::Application
    # config.log_level = :debug

    if defined?(ActiveProfiling)
      config.active_profiling.profiler.enabled = false
      config.active_profiling.profiler.output = :file
      config.active_profiling.profiler.printer = :graph_html
      config.active_profiling.profiler.printer_options = {
        :min_percent => 1,
        :print_file => true
      }
      config.active_profiling.gc_statistics.enabled = true

      config.active_profiling.active_record.backtrace_logger.enabled = true
    end

    # etc...
  end
end

This allows you to tweak some settings without affecting your main application.rb file.

You’ll also want to add the following to your Gemfile:

group :profiling do
  gem 'active-profiling'
  gem 'ruby-prof'
end

License¶ ↑

This gem is licensed under an MIT-style license. See the MIT-LICENSE file for details.