我正在尝试在 Ruby（1.9.3-p0）中使用并发技术，并创建了一个非常简单的、I/O密集型的代理任务。首先，我尝试了非阻塞的方法：
require 'rack'
require 'rack/fiber_pool'
require 'em-http'
require 'em-synchrony'
require 'em-synchrony/em-http'
proxy = lambda {|*|
result = EM::Synchrony.sync EventMachine::HttpRequest.new('http://google.com').get
[200, {}, [result.response]]
}
use Rack::FiberPool, :size => 1000
run proxy
=begin
$ thin -p 3000 -e production -R rack-synchrony.ru start
>> Thin web server (v1.3.1 codename Triple Espresso)
$ ab -c100 -n100 http://localhost:3000/
Concurrency Level: 100
Time taken for tests: 5.602 seconds
HTML transferred: 21900 bytes
Requests per second: 17.85 [#/sec] (mean)
Time per request: 5602.174 [ms] (mean)
=end
哦，我以为一定是我的操作有问题。在这个任务中，我们大部分时间都在等待I/O，平均请求时间竟然是5.6秒？我尝试了另一个：
require 'sinatra'
require 'sinatra/synchrony'
require 'em-synchrony/em-http'
get '/' do
EM::HttpRequest.new("http://google.com").get.response
end
=begin
$ ruby sinatra-synchrony.rb -p 3000 -e production
== Sinatra/1.3.1 has taken the stage on 3000 for production with backup from Thin
>> Thin web server (v1.3.1 codename Triple Espresso)
$ ab -c100 -n100 http://localhost:3000/
Concurrency Level: 100
Time taken for tests: 5.476 seconds
HTML transferred: 21900 bytes
Requests per second: 18.26 [#/sec] (mean)
Time per request: 5475.756 [ms] (mean)
=end
嗯，稍微好一点了，但并不是我所称之为成功的。最后，我尝试了一个线程实现：
require 'rack'
require 'excon'
proxy = lambda {|*|
result = Excon.get('http://google.com')
[200, {}, [result.body]]
}
run proxy
=begin
$ thin -p 3000 -e production -R rack-threaded.ru --threaded --no-epoll start
>> Thin web server (v1.3.1 codename Triple Espresso)
$ ab -c100 -n100 http://localhost:3000/
Concurrency Level: 100
Time taken for tests: 2.014 seconds
HTML transferred: 21900 bytes
Requests per second: 49.65 [#/sec] (mean)
Time per request: 2014.005 [ms] (mean)
=end
这真的非常令人惊讶。难道我漏掉了什么吗？为何EM在这里表现如此糟糕？是否需要进行一些调整？我尝试了各种组合（Unicorn、几个Rainbows配置等等），但它们中没有一个能够接近简单、古老的I/O阻塞线程。
欢迎提出想法、评论和显然更好的实现建议。