diff --git a/powerline/__init__.py b/powerline/__init__.py
index f564bec6..615c5433 100644
--- a/powerline/__init__.py
+++ b/powerline/__init__.py
@@ -412,7 +412,8 @@ class Powerline(object):
 		'''
 		self.shutdown_event.set()
 		if self.use_daemon_threads and self.is_alive():
-			self.thread.join()
+			# Give the worker thread a chance to shutdown, but don't block for too long
+			self.thread.join(.01)
 		self.renderer.shutdown()
 		self.watcher.unsubscribe()
 
diff --git a/powerline/lib/file_watcher.py b/powerline/lib/file_watcher.py
index 0be4be09..83d679ee 100644
--- a/powerline/lib/file_watcher.py
+++ b/powerline/lib/file_watcher.py
@@ -7,10 +7,10 @@ __docformat__ = 'restructuredtext en'
 import os
 import sys
 import errno
-from powerline.lib.time import monotonic
 from time import sleep
 from threading import RLock
 
+from powerline.lib.monotonic import monotonic
 
 class INotifyError(Exception):
 	pass
diff --git a/powerline/lib/memoize.py b/powerline/lib/memoize.py
index 623f1d32..e180f300 100644
--- a/powerline/lib/memoize.py
+++ b/powerline/lib/memoize.py
@@ -1,7 +1,7 @@
 # vim:fileencoding=utf-8:noet
 
 from functools import wraps
-from powerline.lib.time import monotonic
+from powerline.lib.monotonic import monotonic
 
 
 def default_cache_key(**kwargs):
diff --git a/powerline/lib/time.py b/powerline/lib/monotonic.py
similarity index 100%
rename from powerline/lib/time.py
rename to powerline/lib/monotonic.py
diff --git a/powerline/lib/threaded.py b/powerline/lib/threaded.py
index 5c0cfb3c..2e9153f6 100644
--- a/powerline/lib/threaded.py
+++ b/powerline/lib/threaded.py
@@ -2,7 +2,7 @@
 
 from __future__ import absolute_import
 
-from powerline.lib.time import monotonic
+from powerline.lib.monotonic import monotonic
 
 from threading import Thread, Lock, Event
 
@@ -77,7 +77,8 @@ class ThreadedSegment(object):
 	def shutdown(self):
 		self.shutdown_event.set()
 		if self.daemon and self.is_alive():
-			self.thread.join()
+			# Give the worker thread a chance to shutdown, but don't block for too long
+			self.thread.join(.01)
 
 	def set_interval(self, interval=None):
 		# Allowing “interval” keyword in configuration.
diff --git a/powerline/segments/common.py b/powerline/segments/common.py
index 7be327a6..e50615cc 100644
--- a/powerline/segments/common.py
+++ b/powerline/segments/common.py
@@ -7,17 +7,18 @@ import sys
 
 from datetime import datetime
 import socket
-from multiprocessing import cpu_count
+from multiprocessing import cpu_count as _cpu_count
 
 from powerline.lib import add_divider_highlight_group
 from powerline.lib.url import urllib_read, urllib_urlencode
 from powerline.lib.vcs import guess
 from powerline.lib.threaded import ThreadedSegment, KwThreadedSegment, with_docstring
-from powerline.lib.time import monotonic
+from powerline.lib.monotonic import monotonic
 from powerline.lib.humanize_bytes import humanize_bytes
 from powerline.theme import requires_segment_info
 from collections import namedtuple
 
+cpu_count = None
 
 @requires_segment_info
 def hostname(pl, segment_info, only_if_ssh=False, exclude_domain=False):
@@ -245,7 +246,7 @@ def _external_ip(query_url='http://ipv4.icanhazip.com/'):
 
 
 class ExternalIpSegment(ThreadedSegment):
-	interval = 10
+	interval = 300
 
 	def set_state(self, query_url='http://ipv4.icanhazip.com/', **kwargs):
 		self.query_url = query_url
@@ -485,7 +486,7 @@ Also uses ``weather_conditions_{condition}`` for all weather conditions supporte
 ''')
 
 
-def system_load(pl, format='{avg:.1f}', threshold_good=1, threshold_bad=2):
+def system_load(pl, format='{avg:.1f}', threshold_good=1, threshold_bad=2, track_cpu_count=False):
 	'''Return system load average.
 
 	Highlights using ``system_load_good``, ``system_load_bad`` and
@@ -504,6 +505,9 @@ def system_load(pl, format='{avg:.1f}', threshold_good=1, threshold_bad=2):
 		indicates relative position in this interval:
 		(``100 * (cur-good) / (bad-good)``).
 		Note: both parameters are checked against normalized load averages.
+	:param bool track_cpu_count:
+		if True powerline will continuously poll the system to detect changes 
+		in the number of CPUs.
 
 	Divider highlight group used: ``background:divider``.
 
@@ -511,7 +515,7 @@ def system_load(pl, format='{avg:.1f}', threshold_good=1, threshold_bad=2):
 	'''
 	global cpu_count
 	try:
-		cpu_num = cpu_count()
+		cpu_num = cpu_count = _cpu_count() if cpu_count is None or track_cpu_count else cpu_count
 	except NotImplementedError:
 		pl.warn('Unable to get CPU count: method is not implemented')
 		return None
diff --git a/tests/test_segments.py b/tests/test_segments.py
index b95bad62..ca16eb93 100644
--- a/tests/test_segments.py
+++ b/tests/test_segments.py
@@ -231,7 +231,7 @@ class TestCommon(TestCase):
 	def test_system_load(self):
 		pl = Pl()
 		with replace_module_module(common, 'os', getloadavg=lambda: (7.5, 3.5, 1.5)):
-			with replace_attr(common, 'cpu_count', lambda: 2):
+			with replace_attr(common, '_cpu_count', lambda: 2):
 				self.assertEqual(common.system_load(pl=pl),
 						[{'contents': '7.5 ', 'highlight_group': ['system_load_gradient', 'system_load'], 'divider_highlight_group': 'background:divider', 'gradient_level': 100},
 						{'contents': '3.5 ', 'highlight_group': ['system_load_gradient', 'system_load'], 'divider_highlight_group': 'background:divider', 'gradient_level': 75.0},