preforking_em.rb

require 'eventmachine'
require 'socket'
require 'kgio'

server = Kgio::TCPServer.new('0.0.0.0', 4242)

module Dispatch
  def notify_readable
    io = @io.kgio_tryaccept or return
    EventMachine.attach(io, Server)
  end
end

module Server
  def receive_data(data)
    puts Process.pid.to_s << " " << data
    close_connection
  end
end

3.times do
  fork { EM.run { EM.watch(server, Dispatch) { |c| c.notify_readable = true }}}
end

Process.waitall