diff --git a/htdocs/index.wrx b/htdocs/index.wrx
index edf6356..1a7aee9 100644
--- a/htdocs/index.wrx
+++ b/htdocs/index.wrx
@@ -24,7 +24,6 @@
         <title>OpenWebRX | Open Source SDR Web App for Everyone!</title>
         <!-- <script type="text/javascript">
             //Global variables
-            var audio_buffering_fill_to=%[AUDIO_BUFSIZE];
             var server_enable_digimodes=%[DIGIMODES_ENABLE];
 			var mathbox_waterfall_frequency_resolution=%[MATHBOX_WATERFALL_FRES];
 			var mathbox_waterfall_history_length=%[MATHBOX_WATERFALL_THIST];
diff --git a/htdocs/openwebrx.js b/htdocs/openwebrx.js
index efd7ddb..f974730 100644
--- a/htdocs/openwebrx.js
+++ b/htdocs/openwebrx.js
@@ -1185,8 +1185,12 @@ function on_ws_recv(evt)
                     case "smeter":
                         setSmeterAbsoluteValue(json.value);
                     break;
+                    case "cpuusage":
+						var server_cpu_usage = json.value;
+						progressbar_set(e("openwebrx-bar-server-cpu"),server_cpu_usage/100,"Server CPU [" + server_cpu_usage + "%]",server_cpu_usage>85);
+                    break;
                     default:
-                        console.warn('received message of unknown type', json);
+                        console.warn('received message of unknown type: ' + json.type);
 		        }
 		    } catch (e) {
 		        // don't lose exception
diff --git a/owrx/controllers.py b/owrx/controllers.py
index fe4dac2..10009b5 100644
--- a/owrx/controllers.py
+++ b/owrx/controllers.py
@@ -1,7 +1,7 @@
 import mimetypes
 from owrx.websocket import WebSocketConnection
 from owrx.config import PropertyManager
-from owrx.source import SpectrumThread, DspManager
+from owrx.source import SpectrumThread, DspManager, CpuUsageThread
 import json
 
 class Controller(object):
@@ -55,6 +55,8 @@ class SpectrumForwarder(object):
         self.conn.send(bytes([0x02]) + data)
     def write_s_meter_level(self, level):
         self.conn.send({"type":"smeter","value":level})
+    def write_cpu_usage(self, usage):
+        self.conn.send({"type":"cpuusage","value":usage})
 
 class WebSocketMessageHandler(object):
     def __init__(self):
@@ -78,6 +80,7 @@ class WebSocketMessageHandler(object):
 
             self.forwarder = SpectrumForwarder(conn)
             SpectrumThread.getSharedInstance().add_client(self.forwarder)
+            CpuUsageThread.getSharedInstance().add_client(self.forwarder)
 
             self.dsp = DspManager(self.forwarder)
 
@@ -101,6 +104,7 @@ class WebSocketMessageHandler(object):
     def handleClose(self, conn):
         if self.forwarder:
             SpectrumThread.getSharedInstance().remove_client(self.forwarder)
+            CpuUsageThread.getSharedInstance().remove_client(self.forwarder)
         if self.dsp:
             self.dsp.stop()
 
diff --git a/owrx/source.py b/owrx/source.py
index e1ab9e2..2404419 100644
--- a/owrx/source.py
+++ b/owrx/source.py
@@ -2,6 +2,7 @@ import subprocess
 from owrx.config import PropertyManager
 import threading
 import csdr
+import time
 
 class RtlNmuxSource(object):
     def __init__(self):
@@ -157,3 +158,62 @@ class DspManager(object):
 
     def setProperty(self, prop, value):
         self.localProps.getProperty(prop).setValue(value)
+
+class CpuUsageThread(threading.Thread):
+    sharedInstance = None
+    @staticmethod
+    def getSharedInstance():
+        if CpuUsageThread.sharedInstance is None:
+            CpuUsageThread.sharedInstance = CpuUsageThread()
+            CpuUsageThread.sharedInstance.start()
+        return CpuUsageThread.sharedInstance
+
+    def __init__(self):
+        self.clients = []
+        self.doRun = True
+        self.last_worktime = 0
+        self.last_idletime = 0
+        super().__init__()
+
+    def run(self):
+        while self.doRun:
+            time.sleep(3)
+            try:
+                cpu_usage = self.get_cpu_usage()
+            except:
+                cpu_usage = 0
+            for c in self.clients:
+                c.write_cpu_usage(cpu_usage)
+        print("cpu usage thread shut down")
+
+    def get_cpu_usage(self):
+        try:
+            f = open("/proc/stat","r")
+        except:
+            return 0 #Workaround, possibly we're on a Mac
+        line = ""
+        while not "cpu " in line: line=f.readline()
+        f.close()
+        spl = line.split(" ")
+        worktime = int(spl[2]) + int(spl[3]) + int(spl[4])
+        idletime = int(spl[5])
+        dworktime = (worktime - self.last_worktime)
+        didletime = (idletime - self.last_idletime)
+        rate = float(dworktime) / (didletime+dworktime)
+        self.last_worktime = worktime
+        self.last_idletime = idletime
+        if (self.last_worktime==0): return 0
+        return rate
+
+    def add_client(self, c):
+        self.clients.append(c)
+
+    def remove_client(self, c):
+        self.clients.remove(c)
+        if not self.clients:
+            self.shutdown()
+
+    def shutdown(self):
+        print("shutting down cpu usage thread")
+        CpuUsageThread.sharedInstance = None
+        self.doRun = False