require_benchmarks.rb

require 'benchmark'

module Kernel
  alias old_require require

  def require(path)
    #unless caller.find { |caller_line| caller_line.match /dependencies\.rb/ }
    #  return old_require(path)
    #end

    output = nil
    @required_files ||= []

    benchmark = Benchmark.measure do
      output = old_require path
    end

    @required_files << [path, benchmark]

    puts path
    caller.each do |caller_line|
      puts "\t#{caller_line}"
    end
    puts ""

    #puts "#{path}:"
    #puts loading_benchmark

    output
  end

  def print_require_benchmark_stats
    puts "Printing benchmark stats:"
    @required_files ||= []
    @required_files.sort! { |a, b| b[1].real <=> a[1].real }
    @required_files.each do |path, benchmark|
      puts path
      puts benchmark
    end
  end
end

at_exit { print_require_benchmark_stats }

thanks, added memory used from gist#264496, http://gist.github.com/465431