rrdd plugins: Improved accuracy of time reporting.

Signed-off-by: Rok Strniša <rok.strnisa@citrix.com>

ocaml/rrdd/rrdd_main.ml

@@ -558,7 +558,7 @@ let monitor_loop () =
 			try
 				do_monitor xc;
 				Mutex.execute Rrdd_shared.last_loop_end_time_m (fun _ ->
-					Rrdd_shared.last_loop_end_time := Unix.time ()
+					Rrdd_shared.last_loop_end_time := Unix.gettimeofday ()
 				);
 				Thread.delay !Rrdd_shared.timeslice
 			with e ->
@@ -589,6 +589,7 @@ let _ =
 	Debug.set_facility Syslog.Local5;
 
 	(* Read configuration file. *)
+	debug "Reading configuration file ..";
 	read_config ();
 
 	let pidfile = ref "" in

ocaml/rrdd/rrdd_server.ml

@@ -598,14 +598,14 @@ module Plugin = struct
 
 	(* Returns the number of seconds until the next reading phase for the
 	 * sampling frequency given at registration by the plugin with the specified
-	 * unique ID. *)
+	 * unique ID. If the plugin is not registered, -1 is returned. *)
 	let next_reading _ ~(uid : string) : float =
 		let open Rrdd_shared in
 		if Mutex.execute registered_m (fun _ -> Hashtbl.mem registered uid)
 		then Mutex.execute last_loop_end_time_m (fun _ ->
-			!last_loop_end_time +. !timeslice -. (Unix.time ())
+			!last_loop_end_time +. !timeslice -. (Unix.gettimeofday ())
 		)
-		else infinity
+		else -1.
 
 	(* The function registers a plugin, and returns the number of seconds until
 	 * the next reading phase for the specified sampling frequency. *)