diff --git a/tools/python/xen/web/reactor.py b/tools/python/xen/web/reactor.py
index aa8e0c0646..1ebb5c84a0 100644
--- a/tools/python/xen/web/reactor.py
+++ b/tools/python/xen/web/reactor.py
@@ -1,9 +1,2 @@
-from threading import Timer
-
 from unix import listenUNIX, connectUNIX
 from tcp import listenTCP, connectTCP
-
-def callLater(_delay, _fn, *args, **kwds):
-    timer = Timer(_delay, _fn, args=args, kwargs=kwds)
-    timer.start()
-    return timer
diff --git a/tools/python/xen/xend/EventServer.py b/tools/python/xen/xend/EventServer.py
index d9124570dd..ad0128aa06 100644
--- a/tools/python/xen/xend/EventServer.py
+++ b/tools/python/xen/xend/EventServer.py
@@ -5,8 +5,7 @@
 import string
 from threading import Lock
 
-#from twisted.internet import reactor
-from xen.web import reactor
+import scheduler
 
 # subscribe a.b.c h: map a.b.c -> h
 # subscribe a.b.* h: map a.b.* -> h
@@ -130,7 +129,7 @@ class EventServer:
             self.lock.release()
             
         if async:
-            reactor.callLater(0, self.call_handlers, event, val)
+            scheduler.now(self.call_handlers, [event, val])
         else:
             self.call_handlers(event, val)
 
diff --git a/tools/python/xen/xend/XendMigrate.py b/tools/python/xen/xend/XendMigrate.py
index e087475b9d..5264d68f5a 100644
--- a/tools/python/xen/xend/XendMigrate.py
+++ b/tools/python/xen/xend/XendMigrate.py
@@ -12,6 +12,7 @@ import types
 from xen.web import reactor
 from xen.web.protocol import Protocol, ClientFactory
 
+import scheduler
 import sxp
 import XendDB
 import EventServer; eserver = EventServer.instance()
@@ -120,7 +121,7 @@ class SuspendHandler:
 
     def start(self):
         self.subscribe(on=True)
-        timer = reactor.callLater(self.timeout, self.onTimeout)
+        timer = scheduler.later(self.timeout, self.onTimeout)
         try:
             self.readyCond.acquire()
             while not self.ready:
diff --git a/tools/python/xen/xend/server/event.py b/tools/python/xen/xend/server/event.py
index e0096d2d95..f16c786c3e 100644
--- a/tools/python/xen/xend/server/event.py
+++ b/tools/python/xen/xend/server/event.py
@@ -3,6 +3,7 @@ import StringIO
 
 from xen.web import reactor, protocol
 
+from xen.xend import scheduler
 from xen.xend import sxp
 from xen.xend import PrettyPrint
 from xen.xend import EventServer; eserver = EventServer.instance()
@@ -47,7 +48,7 @@ class EventProtocol(protocol.Protocol):
         if self.transport:
             self.transport.loseConnection()
         if self.connected:
-            reactor.callLater(0, self.connectionLost)
+            scheduler.now(self.connectionLost)
 
     def connectionLost(self, reason=None):
         self.unsubscribe()