diff --git a/zipline/core/host.py b/zipline/core/host.py
index 804b25e6..ea1ca0aa 100644
--- a/zipline/core/host.py
+++ b/zipline/core/host.py
@@ -92,6 +92,10 @@ class ComponentHost(object):
     def unregister_component(self, component_id):
         del self.components[component_id]
 
+    @property
+    def pids(self):
+        return [proc.pid for proc in self.subprocesses]
+
     def open(self):
         assert hasattr(self, 'zmq_flavor'), \
         """ You must specify a flavor of ZeroMQ for all Topology
@@ -111,6 +115,7 @@ class ComponentHost(object):
         for component in self.components.itervalues():
             self.launch_component(component)
 
+
     def is_running(self):
         """
         DEPRECATED, left in for compatability for now.
diff --git a/zipline/core/monitor.py b/zipline/core/monitor.py
index 1edf1927..17d8c651 100644
--- a/zipline/core/monitor.py
+++ b/zipline/core/monitor.py
@@ -43,7 +43,7 @@ log = logbook.Logger('Controller')
 # the system.
 
 PARAMETERS = ndict(dict(
-    GENERATIONAL_PERIOD        = 1,
+    GENERATIONAL_PERIOD        = 8,
     ALLOWED_SKIPPED_HEARTBEATS = 3,
     ALLOWED_INVALID_HEARTBEATS = 3,
     PRESTART_HEARBEATS         = 3,
diff --git a/zipline/lines.py b/zipline/lines.py
index 23eb8690..2583672c 100644
--- a/zipline/lines.py
+++ b/zipline/lines.py
@@ -399,16 +399,17 @@ class SimulatedTrading(object):
         # the supervisory layer
 
         # TODO: better way of identifying concurrency substrate
-        if self.sim.zmq_flavor == 'thread':
-            log.debug('Blocking')
-            for thread in self.sim.subthreads:
-                #log.debug('Waiting on %r' % thread)
-                log.debug('Waiting on %r' % thread)
-                thread.join()
-                log.debug('Yielded on %r' % thread)
-        else:
-            for process in self.sim.subprocesses:
-                process.join()
+        if blocking:
+            if self.sim.zmq_flavor == 'thread':
+                log.debug('Blocking')
+                for thread in self.sim.subthreads:
+                    #log.debug('Waiting on %r' % thread)
+                    log.debug('Waiting on %r' % thread)
+                    thread.join()
+                    log.debug('Yielded on %r' % thread)
+            else:
+                for process in self.sim.subprocesses:
+                    process.join()
 
     @property
     def is_success(self):