Profiling

better.png

development_profiler.rb

class DevelopmentProfiler
  
  def self.prof(file_name)
    if Rails.env.development?
      RubyProf.start
      yield
      results = RubyProf.stop
   
      RubyProf::CallTreePrinter.new(results).print({print_file: true})
    else
      yield
    end
 
  end
  
end

example.rb

DevelopmentProfiler.prof('junk') do
  Shitty.new(45000)
end

DevelopmentProfiler.prof('better') do
  Better.new(45000)
end

junk.png

ProfilingGuide.md

Easy steps for CPU profiling a Rails app

1. add ruby-prof to your gemfile (https://github.com/ruby-prof/ruby-prof)
2. grab kcachegrind or qcachegrind (brew install qcachegrind graphviz on os x)
3. plop development_profiler.rb in lib in your app
4. wrap your questionable code in a prof block
5. open the file in qcachegrind

shitty_code.rb

class Shitty
  def initialize(some_int)
    @symbols = (0..some_int).map(&:to_s).map(&:to_sym)
  end
end

class Better
  def initialize(some_int)
    @symbols = (0..some_int).map{|i| i.to_s.to_sym}
  end
end