erb.rb

require 'tilt'
require 'erb'
require 'benchmark'

# http://twitter.com/tiodante/status/60685349868929024
#
# "Sinatra doesn't make ERB slow, Tilt does (and for smaller templates). ERB in
# itself is fast if used properly."

# Testing with a small template:
tpl = "Hello <%= @world %>"

class Scope
  def initialize(world)
    @world = world
  end

  def b; binding; end
end

erb = ERB.new(tpl)
erb.def_method(Scope, :cached_erb)
tilt = Tilt::ERBTemplate.new { tpl }

N = 50_000

scope = Scope.new("World")

Benchmark.bmbm do |x|
  x.report("ERB") { N.times { erb.result(scope.b) } }
  x.report("ERB (cached)") { N.times { scope.cached_erb } }
  x.report("Tilt") { N.times { tilt.render(scope) } }
end

$ ruby erb.rb 
Rehearsal ------------------------------------------------
ERB            2.810000   0.030000   2.840000 (  2.877525)
ERB (cached)   0.140000   0.000000   0.140000 (  0.163492)
Tilt           0.770000   0.010000   0.780000 (  0.798502)
--------------------------------------- total: 3.760000sec

                   user     system      total        real
ERB            3.200000   0.020000   3.220000 (  3.393976)
ERB (cached)   0.130000   0.010000   0.140000 (  0.153053)
Tilt           0.750000   0.000000   0.750000 (  0.758204)