Went from 25% slower partials (vs. 2.3) to 10% faster. More to come.

actionpack/examples/minimal.rb

@@ -70,9 +70,18 @@ class HttpPostController < ActionController::Metal
   end
 end
 
+unless ENV["PROFILE"]
   (ENV["M"] || 1).to_i.times do
     Runner.run(BasePostController.action(:partial), N, 'partial')
     Runner.run(BasePostController.action(:many_partials), N, 'many_partials')
     Runner.run(BasePostController.action(:partial_collection), N, 'collection')
     Runner.run(BasePostController.action(:show_template), N, 'template')
   end
+else
+  require "ruby-prof"
+  RubyProf.start
+  Runner.run(BasePostController.action(:many_partials), N, 'partial')
+  result = RubyProf.stop
+  printer = RubyProf::CallStackPrinter.new(result)
+  printer.print(File.open("output.html", "w"), :min_percent => 2)
+end

actionpack/lib/action_view/render/partials.rb

@@ -177,6 +177,10 @@ module ActionView
         @partial_names ||= Hash.new {|h,k| h[k] = ActiveSupport::ConcurrentHash.new }
       end
 
+      def self.formats
+        @formats ||= Hash.new {|h,k| h[k] = Hash.new {|h,k| h[k] = {}}}
+      end
+
       def initialize(view_context, options, block)
         partial = options[:partial]
 
@@ -187,8 +191,8 @@ module ActionView
 
         # Set up some instance variables to speed up memoizing
         @partial_names  = self.class.partial_names[@view.controller.class]
-        @templates      = Hash.new {|h,k| h[k] = {}}
-        @formats_hash   = view_context.formats.hash
+        @templates      = self.class.formats
+        @details_hash   = [view_context.formats, I18n.locale].hash
 
         # Set up the object and path
         @object         = partial.is_a?(String) ? options[:object] : partial
@@ -248,7 +252,7 @@ module ActionView
 
       def find_template(path = @path)
         return if !path
-        @templates[path][@formats_hash] ||= begin
+        @templates[@details_hash][path][@view.controller_path] ||= begin
           prefix = @view.controller.controller_path unless path.include?(?/)
           @view.find(path, {:formats => @view.formats}, prefix, true)
         end

actionpack/lib/action_view/template/template.rb

@@ -30,12 +30,12 @@ module ActionView
     
     # TODO: Figure out how to abstract this
     def variable_name
-      identifier[%r'_?(\w+)(\.\w+)*$', 1].to_sym
+      @variable_name ||= identifier[%r'_?(\w+)(\.\w+)*$', 1].to_sym
     end
 
     # TODO: Figure out how to abstract this
     def counter_name
-      "#{variable_name}_counter".to_sym
+      @counter_name ||= "#{variable_name}_counter".to_sym
     end
     
     # TODO: kill hax