2 files changed, 50 insertions, 4 deletions
diff --git a/activesupport/lib/active_support/notifications/instrumenter.rb b/activesupport/lib/active_support/notifications/instrumenter.rb
index e99f5ee688..ddcd1661e4 100644
--- a/activesupport/lib/active_support/notifications/instrumenter.rb
+++ b/activesupport/lib/active_support/notifications/instrumenter.rb
@@ -63,6 +63,34 @@ module ActiveSupport
         @end            = ending
         @children       = []
         @duration       = nil
+        @cpu_time_start = nil
+        @cpu_time_finish = nil
+        @allocation_count_start = 0
+        @allocation_count_finish = 0
+      end
+
+      def start!
+        @time = now
+        @cpu_time_start = now_cpu
+        @allocation_count_start = now_allocations
+      end
+
+      def finish!
+        @end = now
+        @cpu_time_finish = now_cpu
+        @allocation_count_finish = now_allocations
+      end
+
+      def cpu_time
+        @cpu_time_finish - @cpu_time_start
+      end
+
+      def idle_time
+        duration - cpu_time
+      end
+
+      def allocations
+        @allocation_count_finish - @allocation_count_start
       end
 
       # Returns the difference in milliseconds between when the execution of the
@@ -88,6 +116,25 @@ module ActiveSupport
       def parent_of?(event)
         @children.include? event
       end
+
+      private
+        def now
+          Process.clock_gettime(Process::CLOCK_MONOTONIC)
+        end
+
+        def now_cpu
+          Process.clock_gettime(Process::CLOCK_PROCESS_CPUTIME_ID)
+        end
+
+        if defined?(JRUBY_VERSION)
+          def now_allocations
+            0
+          end
+        else
+          def now_allocations
+            GC.stat :total_allocated_objects
+          end
+        end
     end
   end
 end
diff --git a/activesupport/lib/active_support/subscriber.rb b/activesupport/lib/active_support/subscriber.rb
index 8ad39f7a05..54c770ac35 100644
--- a/activesupport/lib/active_support/subscriber.rb
+++ b/activesupport/lib/active_support/subscriber.rb
@@ -79,7 +79,8 @@ module ActiveSupport
     end
 
     def start(name, id, payload)
-      e = ActiveSupport::Notifications::Event.new(name, Time.now, nil, id, payload)
+      e = ActiveSupport::Notifications::Event.new(name, nil, nil, id, payload)
+      e.start!
       parent = event_stack.last
       parent << e if parent
 
@@ -87,9 +88,8 @@ module ActiveSupport
     end
 
     def finish(name, id, payload)
-      finished  = Time.now
       event     = event_stack.pop
-      event.end = finished
+      event.finish!
       event.payload.merge!(payload)
 
       method = name.split(".".freeze).first
@@ -97,7 +97,6 @@ module ActiveSupport
     end
 
     private
-
       def event_stack
         SubscriberQueueRegistry.instance.get_queue(@queue_key)
       end