Profiling

better.png

development_profiler.rb

class DevelopmentProfiler
  
  def self.prof(file_name)
    if Rails.env.development?
      RubyProf.start
      yield
      results = RubyProf.stop
   
      File.open "#{Rails.root}/tmp/performance/callgrind.#{file_name}.clt", 'w' do |file|
        RubyProf::CallTreePrinter.new(results).print(file)
      end
    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 (It'll live in tmp/performance in your app)

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

hi @mikeauclair thanks for this gist, but i'm getting this error:

ArgumentError: RubyProf::CallTreePrinter#print cannot print to IO objects
from /Users/luisalfredoporraspaez/.rvm/gems/ruby-2.3.4@webdox/gems/ruby-prof-0.18.0/lib/ruby-prof/printers/call_tree_printer.rb:55:in `validate_print_params'

I found that I can change it with:

RubyProf::CallTreePrinter.new(results).print({print_file: true})

But it creates some files in my directory, example:

profile.callgrind.out.78859
profile.callgrind.out.78859.70346902832000
profile.callgrind.out.78859.70346902838880

I see that they don't have the extension .clt...

I'd give opening the files it generates that way a shot in qcachegrind - I haven't written much Ruby in the past ~4 years, so I wouldn't be shocked if RubyProf's API changed in the intervening time

hi @mikeauclair thanks for this gist, but i'm getting this error:

ArgumentError: RubyProf::CallTreePrinter#print cannot print to IO objects
from /Users/luisalfredoporraspaez/.rvm/gems/ruby-2.3.4@webdox/gems/ruby-prof-0.18.0/lib/ruby-prof/printers/call_tree_printer.rb:55:in `validate_print_params'

I found that I can change it with:

RubyProf::CallTreePrinter.new(results).print({print_file: true})

But it creates some files in my directory, example:

profile.callgrind.out.78859
profile.callgrind.out.78859.70346902832000
profile.callgrind.out.78859.70346902838880

I see that they don't have the extension .clt...

@mikeauclair I could open the file in qcachegrind, I have an example in this gist: https://gist.github.com/lporras/317d25bb0641ad3426851ea06eb8c3ea