   end
 
   defp update_timing(data, key) do
-    time = System.system_time()
+    time = System.monotonic_time()
     %{data | key => data[key] + time - data.timestamp, timestamp: time}
   end
 

  defp update_timing(files, pid, key) do
    Enum.map(files, fn data ->
      if data.pid == pid do
        time = System.system_time()
        %{data | key => data[key] + time - data.timestamp, timestamp: time}
      else
        data

      pid: pid,
      ref: ref,
      file: file,
      timestamp: System.monotonic_time(),
      compiling: 0,
      waiting: 0,
      warned: false
