content_tag.rb

require 'active_support/concern'
require 'active_support/core_ext/object/blank'

require 'action_view/buffers'
require 'action_view/helpers/output_safety_helper'
require 'action_view/helpers/capture_helper'
require 'action_view/helpers/tag_helper'

require 'benchmark/ips'

class Bench
  include ActionView::Helpers::TagHelper

  attr_accessor :output_buffer

  def with_block
    content_tag(:div, class: 'foo bar foo-bar') do
      '<i class="fa fa-euro"></i>'
    end
  end

  def inline
    content_tag(:div, '<i class="fa fa-euro"></i>', class: 'foo bar foo-bar')
  end
end

Benchmark.ips do |x|
  x.report('block') { Bench.new.with_block }
  x.report('inline') { Bench.new.inline }
  x.compare!
end

Warming up --------------------------------------
               block     4.227k i/100ms
              inline     6.647k i/100ms
Calculating -------------------------------------
               block     44.456k (± 3.9%) i/s -    224.031k in   5.047405s
              inline     68.414k (± 4.4%) i/s -    345.644k in   5.062369s

Comparison:
              inline:    68413.5 i/s
               block:    44455.6 i/s - 1.54x slower