io_select_http.rb

class Net::HTTP::BufferedIO < Net::BufferedIO
  @@patch = false
  def self.patch= v; @@patch = v; end

  def rbuf_fill
    return super unless @@patch
    begin
      @rbuf << @io.read_nonblock(BUFSIZE)
    rescue Errno::EWOULDBLOCK, Errno::EAGAIN
      retry unless @read_timeout
      if IO.select([@io], nil, nil, @read_timeout)
        retry
      else
        raise Timeout::Error, 'IO timeout'
      end
    end
  end
end

test.rb

require 'net/http'
require 'benchmark'
require 'io_select_http'

S = '/~apatterson/small.html' # => 150B
M = '/~apatterson/medium.html' # => 71K
L = '/~apatterson/large.html' # => 82M

GC.disable

n = 5000
m = 500
Benchmark.bm(14) do |x|
  small_uri  = URI.parse("http://localhost/#{S}")
  medium_uri = URI.parse("http://localhost/#{M}")
  large_uri  = URI.parse("http://localhost/#{L}")

  #x.report('small') do
  #  n.times do
  #    Net::HTTP.get(small_uri)
  #  end
  #end

  #x.report('small patched') do
  #  Net::HTTP::BufferedIO.patch = true
  #  n.times do
  #    Net::HTTP.get(small_uri)
  #  end
  #  Net::HTTP::BufferedIO.patch = false
  #end

  x.report('medium') do
    m.times do
      Net::HTTP.get(medium_uri)
    end
  end

  x.report('medium patched') do
    Net::HTTP::BufferedIO.patch = true
    m.times do
      Net::HTTP.get(medium_uri)
    end
    Net::HTTP::BufferedIO.patch = false
  end

  #x.report('large') do
  #  Net::HTTP.get(large_uri)
  #end

  #x.report('large patched') do
  #  Net::HTTP::BufferedIO.patch = true
  #  Net::HTTP.get(large_uri)
  #  Net::HTTP::BufferedIO.patch = false
  #end
end