uorb top: measure the elapsed time to give more accurate results

src/modules/uORB/uORBDevices.cpp

@@ -1071,7 +1071,10 @@ void uORB::DeviceMaster::showTop(char **topic_filter, int num_filters)
 	fds.events = POLLIN;
 	bool quit = false;
 
+	hrt_abstime start_time = hrt_absolute_time();
+
 	while (!quit) {
+
 		/* Sleep 200 ms waiting for user input five times ~ 1s */
 		for (int k = 0; k < 5; k++) {
 			char c;
@@ -1092,6 +1095,25 @@ void uORB::DeviceMaster::showTop(char **topic_filter, int num_filters)
 		}
 
 		if (!quit) {
+
+			//update the stats
+			hrt_abstime current_time = hrt_absolute_time();
+			float dt = (current_time - start_time) / 1.e6f;
+			cur_node = first_node;
+
+			while (cur_node) {
+				uint32_t num_lost = cur_node->node->lost_message_count();
+				unsigned int num_msgs = cur_node->node->published_message_count();
+				cur_node->pub_msg_delta = (num_msgs - cur_node->last_pub_msg_count) / dt;
+				cur_node->lost_msg_delta = (num_lost - cur_node->last_lost_msg_count) / dt;
+				cur_node->last_lost_msg_count = num_lost;
+				cur_node->last_pub_msg_count = num_msgs;
+				cur_node = cur_node->next;
+			}
+
+			start_time = current_time;
+
+
 			printf("\033[H"); // move cursor home and clear screen
 			printf(CLEAR_LINE "update: 1s, num topics: %i\n", num_topics);
 #ifdef __PX4_NUTTX
@@ -1102,23 +1124,18 @@ void uORB::DeviceMaster::showTop(char **topic_filter, int num_filters)
 			cur_node = first_node;
 
 			while (cur_node) {
-				uint32_t num_lost = cur_node->node->lost_message_count();
-				unsigned int num_msgs = cur_node->node->published_message_count();
 
-				if (!print_active_only || num_msgs - cur_node->last_pub_msg_count > 0) {
+				if (!print_active_only || cur_node->pub_msg_delta > 0) {
 #ifdef __PX4_NUTTX
 					printf(CLEAR_LINE "%*-s %2i %4i %4i %5i %i\n", (int)max_topic_name_length,
 #else
 					printf(CLEAR_LINE "%*s %2i %4i %4i %5i %i\n", -(int)max_topic_name_length,
 #endif
 					       cur_node->node->meta()->o_name, (int)cur_node->instance,
-					       cur_node->node->subscriber_count(), num_msgs - cur_node->last_pub_msg_count,
-					       num_lost - cur_node->last_lost_msg_count, cur_node->node->queue_size());
+					       cur_node->node->subscriber_count(), cur_node->pub_msg_delta,
+					       cur_node->lost_msg_delta, cur_node->node->queue_size());
 				}
 
-				cur_node->last_lost_msg_count = num_lost;
-				cur_node->last_pub_msg_count = num_msgs;
-
 				cur_node = cur_node->next;
 			}
 

src/modules/uORB/uORBDevices.hpp

@@ -311,6 +311,8 @@ private:
 		uint8_t instance;
 		uint32_t last_lost_msg_count;
 		unsigned int last_pub_msg_count;
+		uint32_t lost_msg_delta;
+		unsigned int pub_msg_delta;
 		DeviceNodeStatisticsData *next = nullptr;
 	};
 	void addNewDeviceNodes(DeviceNodeStatisticsData **first_node, int &num_topics, size_t &max_topic_name_length,