Comparison between Celluloid::IO and Ruby's sockets in Celluloid. Tests were executed on 2.3Ghz macbook. The server was written in node.js and replies a HTTP response.

client1.rb = Celluloid::IO

require 'celluloid/io'
require 'net/http'

t,addr = ARGV[0..1]
t = t.to_i
start = Time.now

class NetHttpBench
  include Celluloid::IO
  def get addr,t
    (0...t).map do |i|
      Net::HTTP.get_response URI("http://#{addr}/#{i}")
    end
  end
end

ret = NetHttpBench.new.get(addr,t).inject(Hash.new){|r,i|
        r[i.code] = (r[i.code]||0) + 1
        r
}

p ret
p (Time.now - start)

client1.rb = Ruby's

require 'celluloid'
require 'net/http'

t,addr = ARGV[0..1]
t = t.to_i
start = Time.now

class Client
  include Celluloid
  def get addr,i
    Net::HTTP.get_response URI("http://#{addr}/#{i}")
  end
end

ret = (0...t).map{|i|
  Client.new.future.get addr,i
}.inject(Hash.new){|r,f|
        v=f.value.code
        r[v] = (r[v]||0) + 1
        r
}

p ret
p (Time.now - start)

Results

$ jruby client1.rb 1000 localhost:4567
{"200"=>1000}
2.206

$ jruby client1.rb 10000 localhost:4567
{"200"=>10000}
8.26

$ jruby client2.rb 1000 localhost:4567
{"200"=>1000}
1.57

$ jruby client2.rb 10000 localhost:4567
ThreadError: unable to create new native thread