time needed to load libs in 'require'

require 'benchmark'
$require_level = 0
module Kernel
  alias require_without_timing require

  def require(path)
    result = seconds = nil

    begin
      $require_level += 1
      seconds = Benchmark.realtime { result = require_without_timing(path) }
    ensure
      $require_level -= 1
    end

    puts "{'%.5f' % seconds} {' '*$require_level}{path}" if result
    result
  end
end