2 files changed, 101 insertions, 2 deletions
diff --git a/activesupport/lib/active_support/notifications/fanout.rb b/activesupport/lib/active_support/notifications/fanout.rb
index 25aab175b4..4e4ca70942 100644
--- a/activesupport/lib/active_support/notifications/fanout.rb
+++ b/activesupport/lib/active_support/notifications/fanout.rb
@@ -70,12 +70,29 @@ module ActiveSupport
 
       module Subscribers # :nodoc:
         def self.new(pattern, listener)
+          subscriber_class = Timed
+
           if listener.respond_to?(:start) && listener.respond_to?(:finish)
-            subscriber = Evented.new pattern, listener
+            subscriber_class = Evented
           else
-            subscriber = Timed.new pattern, listener
+            # Doing all this to detect a block like `proc { |x| }` vs
+            # `proc { |*x| }` or `proc { |**x| }`
+            if listener.respond_to?(:parameters)
+              params = listener.parameters
+              if params.length == 1 && params.first.first == :opt
+                subscriber_class = EventObject
+              end
+            end
           end
 
+          wrap_all pattern, subscriber_class.new(pattern, listener)
+        end
+
+        def self.event_object_subscriber(pattern, block)
+          wrap_all pattern, EventObject.new(pattern, block)
+        end
+
+        def self.wrap_all(pattern, subscriber)
           unless pattern
             AllMessages.new(subscriber)
           else
@@ -130,6 +147,27 @@ module ActiveSupport
           end
         end
 
+        class EventObject < Evented
+          def start(name, id, payload)
+            stack = Thread.current[:_event_stack] ||= []
+            event = build_event name, id, payload
+            event.start!
+            stack.push event
+          end
+
+          def finish(name, id, payload)
+            stack = Thread.current[:_event_stack]
+            event = stack.pop
+            event.finish!
+            @delegate.call event
+          end
+
+          private
+            def build_event(name, id, payload)
+              ActiveSupport::Notifications::Event.new name, nil, nil, id, payload
+            end
+        end
+
         class AllMessages # :nodoc:
           def initialize(delegate)
             @delegate = delegate
diff --git a/activesupport/lib/active_support/notifications/instrumenter.rb b/activesupport/lib/active_support/notifications/instrumenter.rb
index e99f5ee688..f8344912bb 100644
--- a/activesupport/lib/active_support/notifications/instrumenter.rb
+++ b/activesupport/lib/active_support/notifications/instrumenter.rb
@@ -63,6 +63,42 @@ module ActiveSupport
         @end            = ending
         @children       = []
         @duration       = nil
+        @cpu_time_start = nil
+        @cpu_time_finish = nil
+        @allocation_count_start = 0
+        @allocation_count_finish = 0
+      end
+
+      # Record information at the time this event starts
+      def start!
+        @time = now
+        @cpu_time_start = now_cpu
+        @allocation_count_start = now_allocations
+      end
+
+      # Record information at the time this event finishes
+      def finish!
+        @cpu_time_finish = now_cpu
+        @end = now
+        @allocation_count_finish = now_allocations
+      end
+
+      # Returns the CPU time (in milliseconds) passed since the call to
+      # +start!+ and the call to +finish!+
+      def cpu_time
+        (@cpu_time_finish - @cpu_time_start) * 1000
+      end
+
+      # Returns the idle time time (in milliseconds) passed since the call to
+      # +start!+ and the call to +finish!+
+      def idle_time
+        duration - cpu_time
+      end
+
+      # Returns the number of allocations made since the call to +start!+ and
+      # the call to +finish!+
+      def allocations
+        @allocation_count_finish - @allocation_count_start
       end
 
       # Returns the difference in milliseconds between when the execution of the
@@ -88,6 +124,31 @@ module ActiveSupport
       def parent_of?(event)
         @children.include? event
       end
+
+      private
+        def now
+          Process.clock_gettime(Process::CLOCK_MONOTONIC)
+        end
+
+        if defined?(Process::CLOCK_PROCESS_CPUTIME_ID)
+          def now_cpu
+            Process.clock_gettime(Process::CLOCK_PROCESS_CPUTIME_ID)
+          end
+        else
+          def now_cpu
+            0
+          end
+        end
+
+        if defined?(JRUBY_VERSION)
+          def now_allocations
+            0
+          end
+        else
+          def now_allocations
+            GC.stat :total_allocated_objects
+          end
+        end
     end
   end
 end