diff --git a/actionpack/lib/action_controller/metal/url_for.rb b/actionpack/lib/action_controller/metal/url_for.rb
index 85c6b0a9b5..ef1071bb3d 100644
--- a/actionpack/lib/action_controller/metal/url_for.rb
+++ b/actionpack/lib/action_controller/metal/url_for.rb
@@ -5,16 +5,18 @@ module ActionController
     include AbstractController::UrlFor
 
     def url_options
-      options = {}
-      if _routes.equal?(env["action_dispatch.routes"])
-        options[:script_name] = request.script_name.dup
-      end
+      @_url_options ||= begin
+        options = {}
+        if _routes.equal?(env["action_dispatch.routes"])
+          options[:script_name] = request.script_name.dup
+        end
 
-      super.merge(options).reverse_merge(
-        :host => request.host_with_port,
-        :protocol => request.protocol,
-        :_path_segments => request.symbolized_path_parameters
-      )
+        super.merge(options).reverse_merge(
+          :host => request.host_with_port,
+          :protocol => request.protocol,
+          :_path_segments => request.symbolized_path_parameters
+        ).freeze
+      end
     end
   end
 end
diff --git a/actionpack/lib/action_controller/railtie.rb b/actionpack/lib/action_controller/railtie.rb
index aea28d9265..4c57d82f1c 100644
--- a/actionpack/lib/action_controller/railtie.rb
+++ b/actionpack/lib/action_controller/railtie.rb
@@ -26,6 +26,10 @@ module ActionController
       options.stylesheets_dir      ||= paths.public.stylesheets.to_a.first
       options.page_cache_directory ||= paths.public.to_a.first
 
+      # make sure readers methods get compiled
+      options.asset_path           ||= nil
+      options.asset_host           ||= nil
+
       ActiveSupport.on_load(:action_controller) do
         include app.routes.mounted_helpers
         extend ::AbstractController::Railties::RoutesHelpers.with(app.routes)
@@ -33,5 +37,11 @@ module ActionController
         options.each { |k,v| send("#{k}=", v) }
       end
     end
+
+    config.after_initialize do
+      ActiveSupport.on_load(:action_controller) do
+        config.crystalize! if config.respond_to?(:crystalize!)
+      end
+    end
   end
 end
diff --git a/actionpack/lib/action_dispatch/http/url.rb b/actionpack/lib/action_dispatch/http/url.rb
index 2e39d0dbc2..3e5cd6a2f9 100644
--- a/actionpack/lib/action_dispatch/http/url.rb
+++ b/actionpack/lib/action_dispatch/http/url.rb
@@ -15,12 +15,12 @@ module ActionDispatch
 
       # Returns 'https://' if this is an SSL request and 'http://' otherwise.
       def protocol
-        ssl? ? 'https://' : 'http://'
+        @protocol ||= ssl? ? 'https://' : 'http://'
       end
 
       # Is this an SSL request?
       def ssl?
-        @env['HTTPS'] == 'on' || @env['HTTP_X_FORWARDED_PROTO'] == 'https'
+        @ssl ||= @env['HTTPS'] == 'on' || @env['HTTP_X_FORWARDED_PROTO'] == 'https'
       end
 
       # Returns the \host for this request, such as "example.com".
diff --git a/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb b/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
index 02ba5236ee..49e237f8db 100644
--- a/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
+++ b/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
@@ -105,7 +105,7 @@ module ActionDispatch
           else        [ record_or_hash_or_array ]
         end
 
-        inflection = if options[:action].to_s == "new"
+        inflection = if options[:action] && options[:action].to_s == "new"
           args.pop
           :singular
         elsif (record.respond_to?(:persisted?) && !record.persisted?)
@@ -168,10 +168,7 @@ module ActionDispatch
         end
 
         def build_named_route_call(records, inflection, options = {})
-          unless records.is_a?(Array)
-            record = extract_record(records)
-            route  = []
-          else
+          if records.is_a?(Array)
             record = records.pop
             route = records.map do |parent|
               if parent.is_a?(Symbol) || parent.is_a?(String)
@@ -180,6 +177,9 @@ module ActionDispatch
                 ActiveModel::Naming.route_key(parent).singularize
               end
             end
+          else
+            record = extract_record(records)
+            route  = []
           end
 
           if record.is_a?(Symbol) || record.is_a?(String)
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index 1a5f21bd09..eeec10a403 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -334,6 +334,19 @@ module ActionDispatch
       end
 
       class Generator #:nodoc:
+        PARAMETERIZE = {
+          :parameterize => lambda do |name, value|
+            if name == :controller
+              value
+            elsif value.is_a?(Array)
+              value.map { |v| Rack::Mount::Utils.escape_uri(v.to_param) }.join('/')
+            else
+              return nil unless param = value.to_param
+              param.split('/').map { |v| Rack::Mount::Utils.escape_uri(v) }.join("/")
+            end
+          end
+        }
+
         attr_reader :options, :recall, :set, :named_route
 
         def initialize(options, recall, set, extras = false)
@@ -422,7 +435,7 @@ module ActionDispatch
         end
 
         def generate
-          path, params = @set.set.generate(:path_info, named_route, options, recall, opts)
+          path, params = @set.set.generate(:path_info, named_route, options, recall, PARAMETERIZE)
 
           raise_routing_error unless path
 
@@ -430,26 +443,12 @@ module ActionDispatch
 
           return [path, params.keys] if @extras
 
-          path << "?#{params.to_query}" if params.any?
+          path << "?#{params.to_query}" unless params.empty?
           path
         rescue Rack::Mount::RoutingError
           raise_routing_error
         end
 
-        def opts
-          parameterize = lambda do |name, value|
-            if name == :controller
-              value
-            elsif value.is_a?(Array)
-              value.map { |v| Rack::Mount::Utils.escape_uri(v.to_param) }.join('/')
-            else
-              return nil unless param = value.to_param
-              param.split('/').map { |v| Rack::Mount::Utils.escape_uri(v) }.join("/")
-            end
-          end
-          {:parameterize => parameterize}
-        end
-
         def raise_routing_error
           raise ActionController::RoutingError.new("No route matches #{options.inspect}")
         end
diff --git a/actionpack/lib/action_view/base.rb b/actionpack/lib/action_view/base.rb
index 3fa46d0f43..0bef3e3a08 100644
--- a/actionpack/lib/action_view/base.rb
+++ b/actionpack/lib/action_view/base.rb
@@ -209,8 +209,7 @@ module ActionView #:nodoc:
         @_request = controller.request if controller.respond_to?(:request)
       end
 
-      config = controller && controller.respond_to?(:config) ? controller.config : {}
-      @_config = ActiveSupport::InheritableOptions.new(config)
+      @_config = controller && controller.respond_to?(:config) ? controller.config.inheritable_copy : {}
 
       @_content_for  = Hash.new { |h,k| h[k] = ActiveSupport::SafeBuffer.new }
       @_virtual_path = nil
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helper.rb b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
index 687cb83d75..c1dfbe5dc3 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helper.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
@@ -705,19 +705,29 @@ module ActionView
 
       private
 
-        def rewrite_extension?(source, dir, ext)
-          source_ext = File.extname(source)[1..-1]
-          ext && (source_ext.blank? || (ext != source_ext && File.exist?(File.join(config.assets_dir, dir, "#{source}.#{ext}"))))
+        def rewrite_extension(source, dir, ext)
+          source_ext = File.extname(source)
+
+          if source_ext.empty?
+            "#{source}.#{ext}"
+          elsif ext != source_ext[1..-1]
+            with_ext = "#{source}.#{ext}"
+            with_ext if File.exist?(File.join(config.assets_dir, dir, with_ext))
+          end || source
         end
 
         def rewrite_host_and_protocol(source, has_request)
           host = compute_asset_host(source)
-          if has_request && host.present? && !is_uri?(host)
+          if has_request && host && !is_uri?(host)
             host = "#{controller.request.protocol}#{host}"
           end
           "#{host}#{source}"
         end
 
+        def rewrite_relative_url_root(source, relative_url_root)
+          relative_url_root && !source.starts_with?("#{relative_url_root}/") ? "#{relative_url_root}#{source}" : source
+        end
+
         # Add the the extension +ext+ if not present. Return full URLs otherwise untouched.
         # Prefix with <tt>/dir/</tt> if lacking a leading +/+. Account for relative URL
         # roots. Rewrite the asset path for cache-busting asset ids. Include
@@ -725,17 +735,15 @@ module ActionView
         def compute_public_path(source, dir, ext = nil, include_host = true)
           return source if is_uri?(source)
 
-          source += ".#{ext}" if rewrite_extension?(source, dir, ext)
-          source  = "/#{dir}/#{source}" unless source[0] == ?/
+          source = rewrite_extension(source, dir, ext) if ext
+          source = "/#{dir}/#{source}" unless source[0] == ?/
           if controller.respond_to?(:env) && controller.env["action_dispatch.asset_path"]
             source = rewrite_asset_path(source, controller.env["action_dispatch.asset_path"])
           end
           source = rewrite_asset_path(source, config.asset_path)
 
           has_request = controller.respond_to?(:request)
-          if has_request && include_host && source !~ %r{^#{controller.config.relative_url_root}/}
-            source = "#{controller.config.relative_url_root}#{source}"
-          end
+          source = rewrite_relative_url_root(source, controller.config.relative_url_root) if has_request && include_host
           source = rewrite_host_and_protocol(source, has_request) if include_host
 
           source
@@ -802,10 +810,10 @@ module ActionView
           end
 
           asset_id = rails_asset_id(source)
-          if asset_id.blank?
+          if asset_id.empty?
             source
           else
-            source + "?#{asset_id}"
+            "#{source}?#{asset_id}"
           end
         end
 
diff --git a/actionpack/lib/action_view/helpers/url_helper.rb b/actionpack/lib/action_view/helpers/url_helper.rb
index f8147840ed..1c3ca78d28 100644
--- a/actionpack/lib/action_view/helpers/url_helper.rb
+++ b/actionpack/lib/action_view/helpers/url_helper.rb
@@ -95,7 +95,7 @@ module ActionView
       #   # => javascript:history.back()
       def url_for(options = {})
         options ||= {}
-        url = case options
+        case options
         when String
           options
         when Hash
@@ -106,8 +106,6 @@ module ActionView
         else
           polymorphic_path(options)
         end
-
-        url
       end
 
       # Creates a link tag of the given +name+ using a URL created by the set
@@ -586,20 +584,24 @@ module ActionView
 
       private
         def convert_options_to_data_attributes(options, html_options)
-          html_options = {} if html_options.nil?
-          html_options = html_options.stringify_keys
+          if html_options.nil?
+            link_to_remote_options?(options) ? {'data-remote' => 'true'} : {}
+          else
+            html_options = html_options.stringify_keys
+            html_options['data-remote'] = 'true' if link_to_remote_options?(options) || link_to_remote_options?(html_options)
 
-          if (options.is_a?(Hash) && options.key?('remote') && options.delete('remote')) || (html_options.is_a?(Hash) && html_options.key?('remote') && html_options.delete('remote'))
-            html_options['data-remote'] = 'true'
+            confirm = html_options.delete('confirm')
+            method  = html_options.delete('method')
+
+            add_confirm_to_attributes!(html_options, confirm) if confirm
+            add_method_to_attributes!(html_options, method)   if method
+
+            html_options
           end
+        end
 
-          confirm = html_options.delete("confirm")
-          method, href = html_options.delete("method"), html_options['href']
-
-          add_confirm_to_attributes!(html_options, confirm) if confirm
-          add_method_to_attributes!(html_options, method)   if method
-
-          html_options
+        def link_to_remote_options?(options)
+          options.is_a?(Hash) && options.key?('remote') && options.delete('remote')
         end
 
         def add_confirm_to_attributes!(html_options, confirm)
diff --git a/activemodel/lib/active_model/naming.rb b/activemodel/lib/active_model/naming.rb
index fc2abacb6d..2d580fd325 100644
--- a/activemodel/lib/active_model/naming.rb
+++ b/activemodel/lib/active_model/naming.rb
@@ -73,8 +73,10 @@ module ActiveModel
     # Returns an ActiveModel::Name object for module. It can be
     # used to retrieve all kinds of naming-related information.
     def model_name
-      namespace = self.parents.detect { |n| n.respond_to?(:_railtie) }
-      @_model_name ||= ActiveModel::Name.new(self, namespace)
+      @_model_name ||= begin
+        namespace = self.parents.detect { |n| n.respond_to?(:_railtie) }
+        ActiveModel::Name.new(self, namespace)
+      end
     end
 
     # Returns the plural class name of a record or class. Examples:
diff --git a/activesupport/lib/active_support/configurable.rb b/activesupport/lib/active_support/configurable.rb
index 5b85f9394a..1914f10669 100644
--- a/activesupport/lib/active_support/configurable.rb
+++ b/activesupport/lib/active_support/configurable.rb
@@ -9,9 +9,29 @@ module ActiveSupport
   module Configurable
     extend ActiveSupport::Concern
 
+    class Configuration < ActiveSupport::InheritableOptions
+      def crystalize!
+        self.class.crystalize!(keys.reject {|key| respond_to?(key)})
+      end
+
+      # compiles reader methods so we don't have to go through method_missing
+      def self.crystalize!(keys)
+        keys.each do |key|
+          class_eval <<-RUBY, __FILE__, __LINE__ + 1
+            def #{key}; _get(#{key.inspect}); end
+          RUBY
+        end
+      end
+    end
+
     module ClassMethods
       def config
-        @_config ||= ActiveSupport::InheritableOptions.new(superclass.respond_to?(:config) ? superclass.config : {})
+        @_config ||= if superclass.respond_to?(:config)
+          superclass.config.inheritable_copy
+        else
+          # create a new "anonymous" class that will host the compiled reader methods
+          Class.new(Configuration).new
+        end
       end
 
       def configure
@@ -48,7 +68,7 @@ module ActiveSupport
     #   user.config.level          # => 1
     # 
     def config
-      @_config ||= ActiveSupport::InheritableOptions.new(self.class.config)
+      @_config ||= self.class.config.inheritable_copy
     end
   end
 end
diff --git a/activesupport/lib/active_support/core_ext/class/attribute.rb b/activesupport/lib/active_support/core_ext/class/attribute.rb
index 688cba03db..511f26963e 100644
--- a/activesupport/lib/active_support/core_ext/class/attribute.rb
+++ b/activesupport/lib/active_support/core_ext/class/attribute.rb
@@ -72,11 +72,20 @@ class Class
             remove_possible_method(:#{name})
             define_method(:#{name}) { val }
           end
+
+          if singleton_class?
+            class_eval do
+              remove_possible_method(:#{name})
+              def #{name}
+                defined?(@#{name}) ? @#{name} : singleton_class.#{name}
+              end
+            end
+          end
           val
         end
 
         def #{name}
-          defined?(@#{name}) ? @#{name} : singleton_class.#{name}
+          defined?(@#{name}) ? @#{name} : self.class.#{name}
         end
 
         def #{name}?
@@ -87,4 +96,15 @@ class Class
       attr_writer name if instance_writer
     end
   end
+
+  private
+  def singleton_class?
+    # in case somebody is crazy enough to overwrite allocate
+    allocate = Class.instance_method(:allocate)
+    # object.class always points to a real (non-singleton) class
+    allocate.bind(self).call.class != self
+  rescue TypeError
+    # MRI/YARV/JRuby all disallow creating new instances of a singleton class
+    true
+  end
 end
diff --git a/activesupport/lib/active_support/core_ext/hash/keys.rb b/activesupport/lib/active_support/core_ext/hash/keys.rb
index 045a6944fa..d8748b1138 100644
--- a/activesupport/lib/active_support/core_ext/hash/keys.rb
+++ b/activesupport/lib/active_support/core_ext/hash/keys.rb
@@ -35,11 +35,13 @@ class Hash
   # as keys, this will fail.
   #
   # ==== Examples
-  #   { :name => "Rob", :years => "28" }.assert_valid_keys(:name, :age) # => raises "ArgumentError: Unknown key(s): years"
-  #   { :name => "Rob", :age => "28" }.assert_valid_keys("name", "age") # => raises "ArgumentError: Unknown key(s): name, age"
+  #   { :name => "Rob", :years => "28" }.assert_valid_keys(:name, :age) # => raises "ArgumentError: Unknown key: years"
+  #   { :name => "Rob", :age => "28" }.assert_valid_keys("name", "age") # => raises "ArgumentError: Unknown key: name"
   #   { :name => "Rob", :age => "28" }.assert_valid_keys(:name, :age) # => passes, raises nothing
   def assert_valid_keys(*valid_keys)
-    unknown_keys = keys - [valid_keys].flatten
-    raise(ArgumentError, "Unknown key(s): #{unknown_keys.join(", ")}") unless unknown_keys.empty?
+    valid_keys.flatten!
+    each_key do |k|
+      raise(ArgumentError, "Unknown key: #{k}") unless valid_keys.include?(k)
+    end
   end
 end
diff --git a/activesupport/lib/active_support/core_ext/module/attr_internal.rb b/activesupport/lib/active_support/core_ext/module/attr_internal.rb
index 28bc30ae26..00db75bfec 100644
--- a/activesupport/lib/active_support/core_ext/module/attr_internal.rb
+++ b/activesupport/lib/active_support/core_ext/module/attr_internal.rb
@@ -1,16 +1,12 @@
 class Module
   # Declares an attribute reader backed by an internally-named instance variable.
   def attr_internal_reader(*attrs)
-    attrs.each do |attr|
-      module_eval "def #{attr}() #{attr_internal_ivar_name(attr)} end", __FILE__, __LINE__
-    end
+    attrs.each {|attr_name| attr_internal_define(attr_name, :reader)}
   end
 
   # Declares an attribute writer backed by an internally-named instance variable.
   def attr_internal_writer(*attrs)
-    attrs.each do |attr|
-      module_eval "def #{attr}=(v) #{attr_internal_ivar_name(attr)} = v end", __FILE__, __LINE__
-    end
+    attrs.each {|attr_name| attr_internal_define(attr_name, :writer)}
   end
 
   # Declares an attribute reader and writer backed by an internally-named instance
@@ -29,4 +25,15 @@ class Module
     def attr_internal_ivar_name(attr)
       Module.attr_internal_naming_format % attr
     end
+
+    def attr_internal_define(attr_name, type)
+      internal_name = attr_internal_ivar_name(attr_name).sub(/\A@/, '')
+      class_eval do # class_eval is necessary on 1.9 or else the methods a made private
+        # use native attr_* methods as they are faster on some Ruby implementations
+        send("attr_#{type}", internal_name)
+      end
+      attr_name, internal_name = "#{attr_name}=", "#{internal_name}=" if type == :writer
+      alias_method attr_name, internal_name
+      remove_method internal_name
+    end
 end
diff --git a/activesupport/lib/active_support/ordered_options.rb b/activesupport/lib/active_support/ordered_options.rb
index 37e357552c..124e1a74f8 100644
--- a/activesupport/lib/active_support/ordered_options.rb
+++ b/activesupport/lib/active_support/ordered_options.rb
@@ -18,6 +18,9 @@ require 'active_support/ordered_hash'
 #
 module ActiveSupport #:nodoc:
   class OrderedOptions < OrderedHash
+    alias_method :_get, :[] # preserve the original #[] method
+    protected :_get # make it protected
+
     def []=(key, value)
       super(key.to_sym, value)
     end
@@ -36,8 +39,19 @@ module ActiveSupport #:nodoc:
   end
 
   class InheritableOptions < OrderedOptions
-    def initialize(parent)
-      super() { |h,k| parent[k] }
+    def initialize(parent = nil)
+      if parent.kind_of?(OrderedOptions)
+        # use the faster _get when dealing with OrderedOptions
+        super() { |h,k| parent._get(k) }
+      elsif parent
+        super() { |h,k| parent[k] }
+      else
+        super()
+      end
+    end
+
+    def inheritable_copy
+      self.class.new(self)
     end
   end
 end
diff --git a/activesupport/test/configurable_test.rb b/activesupport/test/configurable_test.rb
index cef67e3cf9..4f288eb4d5 100644
--- a/activesupport/test/configurable_test.rb
+++ b/activesupport/test/configurable_test.rb
@@ -39,4 +39,22 @@ class ConfigurableActiveSupport < ActiveSupport::TestCase
     assert_equal :baz, instance.config.foo
     assert_equal :bar, Parent.config.foo
   end
+
+  test "configuration is crystalizeable" do
+    parent = Class.new { include ActiveSupport::Configurable }
+    child  = Class.new(parent)
+
+    parent.config.bar = :foo
+    assert !parent.config.respond_to?(:bar)
+    assert !child.config.respond_to?(:bar)
+    assert !child.new.config.respond_to?(:bar)
+
+    parent.config.crystalize!
+    assert_equal :foo, parent.config.bar
+    assert_equal :foo, child.new.config.bar
+
+    assert_respond_to parent.config, :bar
+    assert_respond_to child.config, :bar
+    assert_respond_to child.new.config, :bar
+  end
 end
\ No newline at end of file
diff --git a/activesupport/test/core_ext/hash_ext_test.rb b/activesupport/test/core_ext/hash_ext_test.rb
index fc8d8170a1..e5438745e0 100644
--- a/activesupport/test/core_ext/hash_ext_test.rb
+++ b/activesupport/test/core_ext/hash_ext_test.rb
@@ -282,7 +282,7 @@ class HashExtTest < Test::Unit::TestCase
       { :failure => "stuff", :funny => "business" }.assert_valid_keys(:failure, :funny)
     end
 
-    assert_raise(ArgumentError, "Unknown key(s): failore") do
+    assert_raise(ArgumentError, "Unknown key: failore") do
       { :failore => "stuff", :funny => "business" }.assert_valid_keys([ :failure, :funny ])
       { :failore => "stuff", :funny => "business" }.assert_valid_keys(:failure, :funny)
     end