diff --git a/activesupport/lib/active_support/notifications/instrumenter.rb b/activesupport/lib/active_support/notifications/instrumenter.rb
index <HASH>..<HASH> 100644
--- a/activesupport/lib/active_support/notifications/instrumenter.rb
+++ b/activesupport/lib/active_support/notifications/instrumenter.rb
@@ -81,14 +81,20 @@ module ActiveSupport
         @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
+        (@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
Match the units in `duration` (milliseconds)