seems slow on 1.9.3

queuetest.rb

#!/usr/bin/env ruby
# -*- coding: UTF-8 -*-;

require 'thread'
require 'time'

class App
  Bus = Struct.new :draw, :visualize
  Info = Struct.new :title, :text

  def start(*params)
    @input_delay, @search_delay, @refresh_rate, @visualize_delay = params
    @bus = Bus.new(Queue.new, Queue.new)

    @input = Thread.new { input }
    @display = Thread.new{ display }
    @visualize = Thread.new{ visualize }

    [@input, @display].each(&:join)
  end

  def cpuload(time)
    s = Time.now
    loop { return if Time.now - s > time }
    sleep 0
  end

  def input
    %w(a ab abc abcd abc).each do |keyword|
      sleep @input_delay
      restart_search(keyword)
    end
  end

  def search(keyword)
    list = []
    5.times do
      cpuload @search_delay
      list << Info.new(keyword, nil)
      @bus.draw.push [:data, list]
    end
  end

  def restart_search(keyword)
    @search.kill if @search
    @search = Thread.new { search keyword }
  end

  def display
    data = nil
    loop do
      sleep @refresh_rate

      refreshed = false
      while message = @bus.draw.shift(true) rescue nil
        refreshed = true
        case message.first
        when :refresh
        when :data
          data = message.last
        end
      end

      next unless refreshed

      puts '--------- result'
      data.each do |v|
        puts v.title
        if v.text
          puts "  #{v.text}"
        else
          @bus.visualize.push v
        end
      end
    end
  end

  def visualize
    while v = @bus.visualize.shift
      cpuload @visualize_delay
      v.text = ([v.title] * (rand(5) + 1)).join(' ')
      @bus.draw.push [:refresh]
    end
  end
end

App.new.start(0.5, 0.1, 0.01, 0.01)