scheduler.rb in async-2.9.0

- old
+ new

@@ -35,13 +35,37 @@
 			@selector = selector || ::IO::Event::Selector.new(Fiber.current)
 			@interrupted = false
 			
 			@blocked = 0
 			
+			@busy_time = 0.0
+			@idle_time = 0.0
+			
 			@timers = ::Timers::Group.new
 		end
 		
+		# Compute the scheduler load according to the busy and idle times that are updated by the run loop.
+		# @returns [Float] The load of the scheduler. 0.0 means no load, 1.0 means fully loaded or over-loaded.
+		def load
+			total_time = @busy_time + @idle_time
+			
+			# If the total time is zero, then the load is zero:
+			return 0.0 if total_time.zero?
+			
+			# We normalize to a 1 second window:
+			if total_time > 1.0
+				ratio = 1.0 / total_time
+				@busy_time *= ratio
+				@idle_time *= ratio
+				
+				# We don't need to divide here as we've already normalised it to a 1s window:
+				return @busy_time
+			else
+				return @busy_time / total_time
+			end
+		end
+		
 		def scheduler_close
 			# If the execution context (thread) was handling an exception, we want to exit as quickly as possible:
 			unless $!
 				self.run
 			end
@@ -265,10 +289,12 @@
 		# When terminating the event loop, we already know we are finished. So we don't need to check the task tree. This is a logical requirement because `run_once` ignores transient tasks. For example, a single top level transient task is not enough to keep the reactor running, but during termination we must still process it in order to terminate child tasks.
 		#
 		# @parameter timeout [Float | Nil] The maximum timeout, or if nil, indefinite.
 		# @returns [Boolean] Whether there is more work to do.
 		private def run_once!(timeout = 0)
+			start_time = Async::Clock.now
+			
 			interval = @timers.wait_interval
 			
 			# If there is no interval to wait (thus no timers), and no tasks, we could be done:
 			if interval.nil?
 				# Allow the user to specify a maximum interval if we would otherwise be sleeping indefinitely:
@@ -285,9 +311,18 @@
 			rescue Errno::EINTR
 				# Ignore.
 			end
 			
 			@timers.fire
+			
+			# Compute load:
+			end_time = Async::Clock.now
+			total_duration = end_time - start_time
+			idle_duration = @selector.idle_duration
+			busy_duration = total_duration - idle_duration
+			
+			@busy_time += busy_duration
+			@idle_time += idle_duration
 			
 			# The reactor still has work to do:
 			return true
 		end
 		