require.rb

class Object
  def require(ruby_file)
    p "Requiring #{ruby_file} ..."
    super
    stats
  end

  def load(ruby_file)
    p "Loading #{ruby_file} ..."
    super
    stats
  end
end

$last_memusage = 0

def memusage
  `ps -o rss= -p #{$$}`.to_i
end

def shrink
  last = memusage
  loop do
    GC.start
    sleep 1
    m = memusage
    break if m == last
    last = m
  end
end

def stats
  shrink
  m = memusage
  delta = m - $last_memusage
  $last_memusage = m
  puts "# #{m}K #{delta >= 0 ? '+' : ''}#{delta}K"
end

Yeah, I did something similar to. Overwriting require is not a bad idea. But the shrink slows the loading down a lot.