From: Zac Medico <zmedico@gentoo.org>
Date: Fri, 17 Feb 2012 10:20:35 +0000 (-0800)
Subject: EventLoop.iteration: run timeouts last
X-Git-Tag: v2.2.0_alpha87~13
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=4a858889202448e93cb43ec2559e9f66c30b09c9;p=portage.git

EventLoop.iteration: run timeouts last

Run timeouts last, in order to minimize latency in termination of
iteration loops that they may control.
---

diff --git a/pym/portage/util/_eventloop/EventLoop.py b/pym/portage/util/_eventloop/EventLoop.py
index 808c83d4c..475a4a9c6 100644
--- a/pym/portage/util/_eventloop/EventLoop.py
+++ b/pym/portage/util/_eventloop/EventLoop.py
@@ -130,10 +130,12 @@ class EventLoop(object):
 						pass
 					if self._run_timeouts():
 						events_handled += 1
-					if not event_handlers:
-						return bool(events_handled)
-				else:
-					return bool(events_handled)
+
+			# If any timeouts have executed, then return immediately,
+			# in order to minimize latency in termination of iteration
+			# loops that they may control.
+			if events_handled or not event_handlers:
+				return bool(events_handled)
 
 		if not event_queue:
 
@@ -149,17 +151,10 @@ class EventLoop(object):
 			else:
 				timeout = 0
 
-			if self._run_timeouts():
-				events_handled += 1
-
 			try:
-
 				self._poll(timeout=timeout)
 			except StopIteration:
-				# This could happen if there are no IO event handlers
-				# after _poll() calls _run_timeouts(), due to them
-				# being removed by timeout or idle callbacks. It can
-				# also be triggered by EINTR which is caused by signals.
+				# This can be triggered by EINTR which is caused by signals.
 				pass
 
 		# NOTE: IO event handlers may be re-entrant, in case something
@@ -172,6 +167,11 @@ class EventLoop(object):
 			if not x.callback(f, event, *x.args):
 				self.source_remove(x.source_id)
 
+		# Run timeouts last, in order to minimize latency in
+		# termination of iteration loops that they may control.
+		if self._run_timeouts():
+			events_handled += 1
+
 		return bool(events_handled)
 
 	def child_watch_add(self, pid, callback, data=None):