Potentially faster boot

application.rb

# THANKS EVERYONE FOR YOUR BELOVED BENCHMARKS.
# THIS PATCH IS NOW IN RAILS:
#
# https://github.com/rails/rails/commit/885a599303585b796da7a0a1c3ccd0bc5c642134 

# Please add the following lines after Bundler.require
# and before "class Application < Rails::Application"
# in your config/application.rb
#
# Notice this is just an experiment, don't leave those
# lines there after the experiment. Then please benchmark
# your app boot time in development before and after adding
# those lines. A simple benchmark is:
#
#   time script/rails runner "MODEL"
#
# Where MODEL is a model available in your app. Also,
# please run the command above at least three times to
# ensure we don't have fake samples. :)
#
# Please post the results in the comments below of the
# benchmarks before and after adding the code. <3
#
# This patch should work on Rails 3.0, 3.1 and master.
#
# Extra: if you could run your app in development and
# production (in your machine!!) with this patch on
# for a couple minutes and report any errors, you will
# win extra <3 <3 <3.

require "active_support/dependencies"

ActiveSupport::Dependencies::WatchStack.class_eval do
  def watching?
    !@watching.empty?
  end
end

def load_dependency(file)
  if ActiveSupport::Dependencies.load? && ActiveSupport::Dependencies.constant_watch_stack.watching?
    ActiveSupport::Dependencies.new_constants_in(Object) { yield }
  else
    yield
  end
rescue Exception => exception  # errors from loading file
  exception.blame_file! file
  raise
end

Ruby 1.9.3-p0, Rails 3.1.3

Before:

5.30s user 0.70s system 99% cpu 6.009 total
5.49s user 0.72s system 98% cpu 6.337 total
5.34s user 0.69s system 99% cpu 6.050 total

After:

4.95s user 0.72s system 99% cpu 5.686 total
4.96s user 0.71s system 99% cpu 5.685 total
5.04s user 0.71s system 99% cpu 5.789 total

Will be leaving the patch in today and I'll report any issues...

Ruby 1.9.2, Rails 3.1, openSUSE 12.1

Before

---

real 0m30.473s
user 0m29.551s
sys 0m0.771s

---

real 0m31.978s
user 0m30.984s
sys 0m0.892s

---

real 0m31.855s
user 0m30.922s
sys 0m0.823s

---

---

After

---

real 0m30.095s
user 0m29.201s
sys 0m0.810s

---

real 0m30.118s
user 0m29.303s
sys 0m0.731s

---

real 0m30.385s
user 0m29.494s
sys 0m0.805s

---

With JRuby 1.6.4

Before

λ  time script/rails runner Advisor

real    0m11.627s
user    0m23.053s
sys 0m0.967s

After

 λ  time script/rails runner Advisor

real    0m11.437s
user    0m23.101s
sys 0m0.987s

No much difference.

Sorry... ignore the error i reported... accidentally deleted the Bundler.require... doh

ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-darwin11.0.0]
Rails 3.0.9

Before:
13,37s user 1,03s system 100% cpu 14,397 total
13,42s user 1,05s system 99% cpu 14,468 total
13,48s user 1,06s system 100% cpu 14,534 total

After:
13,21s user 1,07s system 99% cpu 14,394 total
13,37s user 1,06s system 99% cpu 14,433 total
13,34s user 1,06s system 100% cpu 14,391 total

No actual improvement noticed...

Rails 3.0.10
ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-darwin11.1.0]

Before:

 real    0m38.392s
 user    0m35.857s
 sys     0m2.511s

After:

 real    0m36.849s
 user    0m34.325s
 sys     0m2.443s 

---

Same app with ruby 1.9.3p0 (2011-10-30 revision 33570) [x86_64-darwin11.1.0]

Before:

 real    0m17.713s 
 user    0m14.797s
 sys     0m1.444s

After:

 real    0m15.556s
 user    0m14.086s
 sys     0m1.400s

Thanks everyone for your beloved benchmarks. This patch is now in Rails:

rails/rails@885a599