Small optimization in epoll loop

neo/lib/connection.py

@@ -482,6 +482,7 @@ class Connection(BaseConnection):
     def readable(self):
         """Called when self is readable."""
         # last known remote activity
+        empty_queue = not self._queue
         try:
             try:
                 if self.connector.receive(self.read_buf):
@@ -499,7 +500,7 @@ class Connection(BaseConnection):
         except PacketMalformedError, e:
             logging.error('malformed packet from %r: %s', self, e)
             self._closure()
-        return not not self._queue
+        return empty_queue and not not self._queue
 
     def hasPendingMessages(self):
         """

neo/lib/event.py

@@ -15,6 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
+from collections import deque
 from time import time
 from select import epoll, EPOLLIN, EPOLLOUT, EPOLLERR, EPOLLHUP
 from errno import EAGAIN, EEXIST, EINTR, ENOENT
@@ -41,7 +42,7 @@ class EpollEventManager(object):
         self.reader_set = set()
         self.writer_set = set()
         self.epoll = epoll()
-        self._pending_processing = []
+        self._pending_processing = deque()
         self._trigger_list = []
         self._trigger_fd, w = os.pipe()
         os.close(w)
@@ -112,12 +113,13 @@ class EpollEventManager(object):
             self.addReader(conn)
 
     def unregister(self, conn, close=False):
-        new_pending_processing = [x for x in self._pending_processing
-                                  if x is not conn]
-        # Check that we removed at most one entry from
-        # self._pending_processing .
-        assert len(new_pending_processing) > len(self._pending_processing) - 2
-        self._pending_processing = new_pending_processing
+        try:
+            self._pending_processing.remove(conn)
+        except ValueError:
+            pass
+        else:
+            # Check that there was no duplicate.
+            assert conn not in self._pending_processing
         connector = conn.getConnector()
         fd = connector.getDescriptor()
         try:
@@ -144,24 +146,18 @@ class EpollEventManager(object):
     def isIdle(self):
         return not (self._pending_processing or self.writer_set)
 
-    def _addPendingConnection(self, conn):
-        pending_processing = self._pending_processing
-        if conn not in pending_processing:
-            pending_processing.append(conn)
-
     def poll(self, blocking=1):
-        if not self._pending_processing:
-            # Fetch messages from polled file descriptors
+        pending_processing = self._pending_processing
+        if not pending_processing:
             self._poll(blocking)
-            if not self._pending_processing:
+            if not pending_processing:
                 return
-        to_process = self._pending_processing.pop(0)
+        to_process = pending_processing.popleft()
         try:
             to_process.process()
         finally:
-            # ...and requeue if there are pending messages
             if to_process.hasPendingMessages():
-                self._addPendingConnection(to_process)
+                pending_processing.append(to_process)
         # Non-blocking call: as we handled a packet, we should just offer
         # poll a chance to fetch & send already-available data, but it must
         # not delay us.
@@ -209,6 +205,7 @@ class EpollEventManager(object):
             return
         else:
             if event_list:
+                pending_processing = self._pending_processing
                 wlist = []
                 elist = []
                 for fd, event in event_list:
@@ -218,7 +215,7 @@ class EpollEventManager(object):
                         except KeyError:
                             continue
                         if conn.readable():
-                            self._addPendingConnection(conn)
+                            pending_processing.append(conn)
                     if event & EPOLLOUT:
                         wlist.append(fd)
                     if event & (EPOLLERR | EPOLLHUP):
@@ -244,7 +241,7 @@ class EpollEventManager(object):
                                     del action_list[:]
                         continue
                     if conn.readable():
-                        self._addPendingConnection(conn)
+                        pending_processing.append(conn)
                 return
         finally:
             self._closeRelease()