Add script/rubyprof to generate cachegrind callgraphs

Gemfile

@@ -28,6 +28,7 @@ gem 'test-unit' if RUBY_PLATFORM =~ /cygwin/ || RUBY_VERSION.start_with?("2.2")
 gem 'rspec-mocks'
 
 if ENV['BENCHMARK']
+  gem 'ruby-prof'
   gem 'rbtrace'
   gem 'stackprof'
   gem 'benchmark-ips'

script/rubyprof

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+export BENCHMARK=1
+
+TEST_SCRIPT="Jekyll::Commands::Build.process({'source' => 'site', 'full_rebuild' => true})"
+
+RUBY=$(cat <<RUBY
+  require 'ruby-prof'
+  result = RubyProf.profile{ ${TEST_SCRIPT} }
+  printer = RubyProf::CallTreePrinter.new(result)
+  filename = "tmp/ruby_prof_#{rand 10000}"
+  puts "Writing profile to #{filename}"
+  file = File.open(filename, "w")
+  printer.print(file, {})
+  file.close
+RUBY
+)
+
+bundle exec ruby -r ./lib/jekyll -e "${RUBY}"