str_freeze.rb

#! /usr/bin/env ruby

GC.disable

require "objspace"

FMT = <<STATS.freeze
before   %10d
after    %10d
         ----------
         %10d
STATS

N = Integer(ARGV.first || 10_000)

def profile(&block)
  GC.start

  before = ObjectSpace.count_objects[:T_STRING]

  N.times { block.call }

  after = ObjectSpace.count_objects[:T_STRING]

  puts FMT % [before, after, (after - before)]

  GC.start
end

puts "Iterating #{N} times".freeze

puts

puts "String".freeze
profile { "lorem" }

puts

puts "Frozen string".freeze
profile { "ipsum".freeze }