Add logging for GC (slight slowdown, but worth it for the data)

app/controllers/application_controller.rb

@@ -11,6 +11,7 @@ class ApplicationController < ActionController::Base
   before_filter :set_invites
   before_filter :set_locale
   before_filter :which_action_and_user
+  prepend_before_filter :clear_gc_stats
 
   def set_contacts_notifications_and_status
     if user_signed_in?
@@ -50,4 +51,7 @@ class ApplicationController < ActionController::Base
       I18n.locale = request.compatible_language_from AVAILABLE_LANGUAGE_CODES
     end
   end
+  def clear_gc_stats
+    GC.clear_stats if GC.respond_to?(:clear_stats)
+  end
 end

config/environments/production.rb

@@ -51,3 +51,4 @@ end
 
 # Sacrifice readability for a 10% performance boost
 Haml::Template::options[:ugly] = true
+GC.enable_stats if GC.respond_to?(:enable_stats)

lib/log_overrider.rb

@@ -19,6 +19,7 @@ module ActionDispatch
 
         ActiveSupport::Deprecation.silence do
           message = "event=error error_class=#{exception.class} error_message='#{exception.message}' "
+          message << "gc_ms=#{GC.time} gc_collections=#{GC.collections} gc_bytes=#{GC.growth} " if GC.respond_to?(:enable_stats)
           message << "orig_error_message='#{exception.original_exception.message}'" if exception.respond_to?(:original_exception)
           message << "annotated_source='#{exception.annoted_source_code.to_s}' " if exception.respond_to?(:annoted_source_code)
           message << "app_backtrace='#{application_trace(exception).join(";")}'"
@@ -41,6 +42,7 @@ class ActionController::LogSubscriber
     log_string = "event=request_completed status=#{payload[:status]} "
     log_string << "controller=#{payload[:controller]} action=#{payload[:action]} format=#{payload[:formats].first.to_s.upcase} "
     log_string << "ms=#{"%.0f" % event.duration} "
+    log_string << "gc_ms=#{GC.time} gc_collections=#{GC.collections} gc_bytes=#{GC.growth} " if GC.respond_to?(:enable_stats)
     log_string << "params='#{params.inspect}' " unless params.empty?
     #log_string << "additions='#{additions.join(" | ")}' " unless additions.blank?