diff --git a/coretk/coretk/coreclient.py b/coretk/coretk/coreclient.py
index 05a36c82..e2aef5a2 100644
--- a/coretk/coretk/coreclient.py
+++ b/coretk/coretk/coreclient.py
@@ -411,7 +411,7 @@ class CoreClient:
         else:
             emane_config = None
 
-        start = time.time()
+        start = time.perf_counter()
         response = self.client.start_session(
             self.session_id,
             nodes,
@@ -425,7 +425,7 @@ class CoreClient:
             service_configs,
             file_configs,
         )
-        process_time = time.time() - start
+        process_time = time.perf_counter() - start
         logging.debug("start session(%s), result: %s", self.session_id, response.result)
         self.app.statusbar.start_session_callback(process_time)
 
@@ -439,9 +439,9 @@ class CoreClient:
     def stop_session(self, session_id=None):
         if not session_id:
             session_id = self.session_id
-        start = time.time()
+        start = time.perf_counter()
         response = self.client.stop_session(session_id)
-        process_time = time.time() - start
+        process_time = time.perf_counter() - start
         self.app.statusbar.stop_session_callback(process_time)
         logging.debug("stopped session(%s), result: %s", session_id, response.result)
 
diff --git a/coretk/coretk/menuaction.py b/coretk/coretk/menuaction.py
index d8dc89cb..1a64800c 100644
--- a/coretk/coretk/menuaction.py
+++ b/coretk/coretk/menuaction.py
@@ -33,10 +33,10 @@ class MenuAction:
 
     def cleanup_old_session(self, quitapp=False):
         logging.info("cleaning up old session")
-        start = time.time()
+        start = time.perf_counter()
         self.app.core.stop_session()
         self.app.core.delete_session()
-        process_time = time.time() - start
+        process_time = time.perf_counter() - start
         self.app.statusbar.stop_session_callback(process_time)
         if quitapp:
             self.app.quit()
diff --git a/daemon/core/api/grpc/server.py b/daemon/core/api/grpc/server.py
index a914d617..6a6747f1 100644
--- a/daemon/core/api/grpc/server.py
+++ b/daemon/core/api/grpc/server.py
@@ -660,7 +660,7 @@ class CoreGrpcServer(core_pb2_grpc.CoreApiServicer):
         last_check = None
         last_stats = None
         while self._is_running(context):
-            now = time.time()
+            now = time.monotonic()
             stats = get_net_stats()
 
             # calculate average
diff --git a/daemon/core/api/tlv/corehandlers.py b/daemon/core/api/tlv/corehandlers.py
index 321306a2..009cb067 100644
--- a/daemon/core/api/tlv/corehandlers.py
+++ b/daemon/core/api/tlv/corehandlers.py
@@ -1710,7 +1710,7 @@ class CoreHandler(socketserver.BaseRequestHandler):
             event_type=event_type,
             name=name,
             data=fail_data + ";" + unknown_data,
-            time=str(time.time()),
+            time=str(time.monotonic()),
         )
 
         self.session.broadcast_event(event_data)
diff --git a/daemon/core/emulator/session.py b/daemon/core/emulator/session.py
index fee2bde4..1a01bdaa 100644
--- a/daemon/core/emulator/session.py
+++ b/daemon/core/emulator/session.py
@@ -103,7 +103,7 @@ class Session:
 
         # TODO: should the default state be definition?
         self.state = EventTypes.NONE.value
-        self._state_time = time.time()
+        self._state_time = time.monotonic()
         self._state_file = os.path.join(self.session_dir, "state")
 
         # hooks handlers
@@ -1030,7 +1030,7 @@ class Session:
             return
 
         self.state = state_value
-        self._state_time = time.time()
+        self._state_time = time.monotonic()
         logging.info("changing session(%s) to state %s", self.id, state_name)
 
         self.write_state(state_value)
@@ -1038,7 +1038,7 @@ class Session:
         self.run_state_hooks(state_value)
 
         if send_event:
-            event_data = EventData(event_type=state_value, time=str(time.time()))
+            event_data = EventData(event_type=state_value, time=str(time.monotonic()))
             self.broadcast_event(event_data)
 
     def write_state(self, state):
@@ -1821,7 +1821,7 @@ class Session:
         if not in runtime.
         """
         if self.state == EventTypes.RUNTIME_STATE.value:
-            return time.time() - self._state_time
+            return time.monotonic() - self._state_time
         else:
             return 0.0
 
diff --git a/daemon/core/location/event.py b/daemon/core/location/event.py
index 11e535d3..f930d9b7 100644
--- a/daemon/core/location/event.py
+++ b/daemon/core/location/event.py
@@ -145,7 +145,7 @@ class EventLoop:
             with self.lock:
                 if not self.running or not self.queue:
                     break
-                now = time.time()
+                now = time.monotonic()
                 if self.queue[0].time > now:
                     schedule = True
                     break
@@ -170,7 +170,7 @@ class EventLoop:
                 raise ValueError("scheduling event while not running")
             if not self.queue:
                 return
-            delay = self.queue[0].time - time.time()
+            delay = self.queue[0].time - time.monotonic()
             if self.timer:
                 raise ValueError("timer was already set")
             self.timer = Timer(delay, self.__run_events)
@@ -187,7 +187,7 @@ class EventLoop:
             if self.running:
                 return
             self.running = True
-            self.start = time.time()
+            self.start = time.monotonic()
             for event in self.queue:
                 event.time += self.start
             self.__schedule_event()
@@ -225,7 +225,7 @@ class EventLoop:
             self.eventnum += 1
             evtime = float(delaysec)
             if self.running:
-                evtime += time.time()
+                evtime += time.monotonic()
             event = Event(eventnum, evtime, func, *args, **kwds)
 
             if self.queue:
diff --git a/daemon/core/location/mobility.py b/daemon/core/location/mobility.py
index 6a796526..b3eb4884 100644
--- a/daemon/core/location/mobility.py
+++ b/daemon/core/location/mobility.py
@@ -174,7 +174,7 @@ class MobilityManager(ModelManager):
             event_type=event_type,
             name=f"mobility:{model.name}",
             data=data,
-            time=str(time.time()),
+            time=str(time.monotonic()),
         )
 
         self.session.broadcast_event(event_data)
@@ -612,7 +612,7 @@ class WayPointMobility(WirelessModel):
         if self.state != self.STATE_RUNNING:
             return
         t = self.lasttime
-        self.lasttime = time.time()
+        self.lasttime = time.monotonic()
         now = self.lasttime - self.timezero
         dt = self.lasttime - t
 
@@ -664,7 +664,7 @@ class WayPointMobility(WirelessModel):
         :return: nothing
         """
         logging.info("running mobility scenario")
-        self.timezero = time.time()
+        self.timezero = time.monotonic()
         self.lasttime = self.timezero - (0.001 * self.refresh_ms)
         self.movenodesinitial()
         self.runround()
@@ -844,7 +844,7 @@ class WayPointMobility(WirelessModel):
             self.lasttime = 0
             self.run()
         elif laststate == self.STATE_PAUSED:
-            now = time.time()
+            now = time.monotonic()
             self.timezero += now - self.lasttime
             self.lasttime = now - (0.001 * self.refresh_ms)
             self.runround()
@@ -871,7 +871,7 @@ class WayPointMobility(WirelessModel):
         :return: nothing
         """
         self.state = self.STATE_PAUSED
-        self.lasttime = time.time()
+        self.lasttime = time.monotonic()
 
 
 class Ns2ScriptedMobility(WayPointMobility):
diff --git a/daemon/core/nodes/network.py b/daemon/core/nodes/network.py
index 6fe291dd..f0639649 100644
--- a/daemon/core/nodes/network.py
+++ b/daemon/core/nodes/network.py
@@ -57,7 +57,7 @@ class EbtablesQueue:
         :return: nothing
         """
         with self.updatelock:
-            self.last_update_time[wlan] = time.time()
+            self.last_update_time[wlan] = time.monotonic()
 
         if self.doupdateloop:
             return
@@ -108,9 +108,9 @@ class EbtablesQueue:
         :rtype: float
         """
         try:
-            elapsed = time.time() - self.last_update_time[wlan]
+            elapsed = time.monotonic() - self.last_update_time[wlan]
         except KeyError:
-            self.last_update_time[wlan] = time.time()
+            self.last_update_time[wlan] = time.monotonic()
             elapsed = 0.0
 
         return elapsed
@@ -122,7 +122,7 @@ class EbtablesQueue:
         :param wlan: wlan entity
         :return: nothing
         """
-        self.last_update_time[wlan] = time.time()
+        self.last_update_time[wlan] = time.monotonic()
         self.updates.remove(wlan)
 
     def updateloop(self):
diff --git a/daemon/core/services/coreservices.py b/daemon/core/services/coreservices.py
index 80168425..361061be 100644
--- a/daemon/core/services/coreservices.py
+++ b/daemon/core/services/coreservices.py
@@ -538,13 +538,13 @@ class CoreServices:
             time.sleep(service.validation_timer)
         # non-blocking, attempt to validate periodically, up to validation_timer time
         elif service.validation_mode == ServiceMode.NON_BLOCKING:
-            start = time.time()
+            start = time.monotonic()
             while True:
                 status = self.validate_service(node, service)
                 if not status:
                     break
 
-                if time.time() - start > service.validation_timer:
+                if time.monotonic() - start > service.validation_timer:
                     break
 
                 time.sleep(service.validation_period)
diff --git a/daemon/tests/test_grpc.py b/daemon/tests/test_grpc.py
index 28005dbb..56523e81 100644
--- a/daemon/tests/test_grpc.py
+++ b/daemon/tests/test_grpc.py
@@ -1042,7 +1042,7 @@ class TestGrpc:
             client.events(session.id, handle_event)
             time.sleep(0.1)
             event = EventData(
-                event_type=EventTypes.RUNTIME_STATE.value, time=str(time.time())
+                event_type=EventTypes.RUNTIME_STATE.value, time=str(time.monotonic())
             )
             session.broadcast_event(event)
 
diff --git a/daemon/tests/test_gui.py b/daemon/tests/test_gui.py
index c2a8c9fc..91324d08 100644
--- a/daemon/tests/test_gui.py
+++ b/daemon/tests/test_gui.py
@@ -523,7 +523,7 @@ class TestGui:
             MessageFlags.ADD.value,
             [
                 (EventTlvs.TYPE, EventTypes.SCHEDULED.value),
-                (EventTlvs.TIME, str(time.time() + 100)),
+                (EventTlvs.TIME, str(time.monotonic() + 100)),
                 (EventTlvs.NODE, node.id),
                 (EventTlvs.NAME, "event"),
                 (EventTlvs.DATA, "data"),