diff --git a/setup.py b/setup.py
index aa40fa9e..c15f8850 100644
--- a/setup.py
+++ b/setup.py
@@ -345,6 +345,10 @@ def params():
 		# documentation dependencies
 		install_requires = install_requires + extras_require['develop']
 
+	import sys
+	if sys.platform in ("linux2", "darwin"):
+		install_requires += ["monotime"]
+
 	entry_points = {
 		"console_scripts": [
 			"octoprint = octoprint:main"
diff --git a/src/octoprint/server/__init__.py b/src/octoprint/server/__init__.py
index 206d17f6..c9a6daec 100644
--- a/src/octoprint/server/__init__.py
+++ b/src/octoprint/server/__init__.py
@@ -58,6 +58,7 @@ import octoprint.filemanager.analysis
 import octoprint.slicing
 
 from . import util
+util.tornado.fix_ioloop_scheduling()
 
 
 UI_API_KEY = ''.join('%02X' % ord(z) for z in uuid.uuid4().bytes)
@@ -655,6 +656,11 @@ class Server():
 			app.register_blueprint(blueprint, url_prefix=url_prefix)
 			logger.debug("Registered API of plugin {name} under URL prefix {url_prefix}".format(name=name, url_prefix=url_prefix))
 
+		## Tornado initialization starts here
+
+		ioloop = IOLoop()
+		ioloop.install()
+
 		self._router = SockJSRouter(self._createSocketConnection, "/sockjs")
 
 		upload_suffixes = dict(name=settings().get(["server", "uploads", "nameSuffix"]), path=settings().get(["server", "uploads", "pathSuffix"]))
@@ -684,8 +690,6 @@ class Server():
 		observer.schedule(util.watchdog.GcodeWatchdogHandler(fileManager, printer), settings().getBaseFolder("watched"))
 		observer.start()
 
-		ioloop = IOLoop.instance()
-
 		# run our startup plugins
 		octoprint.plugin.call_plugin(octoprint.plugin.StartupPlugin,
 		                             "on_startup",
diff --git a/src/octoprint/server/util/tornado.py b/src/octoprint/server/util/tornado.py
index 18e7281a..399dd4d7 100644
--- a/src/octoprint/server/util/tornado.py
+++ b/src/octoprint/server/util/tornado.py
@@ -29,6 +29,36 @@ import tornado.util
 import octoprint.util
 
 
+#~~ Monkey patching
+
+
+def fix_ioloop_scheduling():
+	"""
+	This monkey patches tornado's :meth:`tornado.ioloop.PeriodicCallback._schedule_next` method so it no longer
+	blocks for long times on slow machines (RPi) when the system time happens to change by a large amount (e.g. due to
+	the first ever contact to an NTP server).
+
+	Patch by @nosyjoe on Github. See this PR against tornado: https://github.com/tornadoweb/tornado/pull/1290
+	"""
+
+	import math
+
+	# patched implementation taken from PR
+	def _schedule_next(self):
+		if self._running:
+			current_time = self.io_loop.time()
+
+			if self._next_timeout <= current_time:
+				callback_time_sec = self.callback_time / 1000.0
+				self._next_timeout += (math.floor((current_time - self._next_timeout) / callback_time_sec) + 1) * callback_time_sec
+
+			self._timeout = self.io_loop.add_timeout(self._next_timeout, self._run)
+
+	# replace original implementation with patched version
+	import tornado.ioloop
+	tornado.ioloop.PeriodicCallback._schedule_next = _schedule_next
+
+
 #~~ WSGI middleware