Maptick lag minimization port (#12066)

* extools.dll

* backend

* queued pipenet builds

* oh yeah we don't have that

* wow

* Update air.dm

code/controllers/master.dm

@@ -35,6 +35,9 @@ GLOBAL_REAL(Master, /datum/controller/master) = new
 
 	var/sleep_delta = 1
 
+	///Only run ticker subsystems for the next n ticks.
+	var/skip_ticks = 0
+
 	var/make_runtime = 0
 
 	var/initializations_finished_with_no_players_logged_in	//I wonder what this could be?
@@ -334,7 +337,7 @@ GLOBAL_REAL(Master, /datum/controller/master) = new
 			new/datum/controller/failsafe() // (re)Start the failsafe.
 
 		//now do the actual stuff
-		if (!queue_head || !(iteration % 3))
+		if (!skip_ticks)
 			var/checking_runlevel = current_runlevel
 			if(cached_runlevel != checking_runlevel)
 				//resechedule subsystems
@@ -380,6 +383,8 @@ GLOBAL_REAL(Master, /datum/controller/master) = new
 
 		iteration++
 		last_run = world.time
+		if (skip_ticks)
+			skip_ticks--
 		src.sleep_delta = MC_AVERAGE_FAST(src.sleep_delta, sleep_delta)
 		current_ticklimit = TICK_LIMIT_RUNNING
 		if (processing * sleep_delta <= world.tick_lag)
@@ -443,10 +448,12 @@ GLOBAL_REAL(Master, /datum/controller/master) = new
 		while (queue_node)
 			if (ran && TICK_USAGE > TICK_LIMIT_RUNNING)
 				break
-
 			queue_node_flags = queue_node.flags
 			queue_node_priority = queue_node.queued_priority
 
+			if (!(queue_node_flags & SS_TICKER) && skip_ticks)
+				queue_node = queue_node.queue_next
+				continue
 			//super special case, subsystems where we can't make them pause mid way through
 			//if we can't run them this tick (without going over a tick)
 			//we bump up their priority and attempt to run them next tick
@@ -454,14 +461,15 @@ GLOBAL_REAL(Master, /datum/controller/master) = new
 			//	in those cases, so we just let them run)
 			if (queue_node_flags & SS_NO_TICK_CHECK)
 				if (queue_node.tick_usage > TICK_LIMIT_RUNNING - TICK_USAGE && ran_non_ticker)
-					queue_node.queued_priority += queue_priority_count * 0.1
-					queue_priority_count -= queue_node_priority
-					queue_priority_count += queue_node.queued_priority
-					current_tick_budget -= queue_node_priority
-					queue_node = queue_node.queue_next
+					if (!(queue_node_flags & SS_BACKGROUND))
+						queue_node.queued_priority += queue_priority_count * 0.1
+						queue_priority_count -= queue_node_priority
+						queue_priority_count += queue_node.queued_priority
+						current_tick_budget -= queue_node_priority
+						queue_node = queue_node.queue_next
 					continue
 
-			if ((queue_node_flags & SS_BACKGROUND) && !bg_calc)
+			if (!bg_calc && (queue_node_flags & SS_BACKGROUND))
 				current_tick_budget = queue_priority_count_bg
 				bg_calc = TRUE
 
@@ -514,7 +522,7 @@ GLOBAL_REAL(Master, /datum/controller/master) = new
 			queue_node.paused_ticks = 0
 			queue_node.paused_tick_usage = 0
 
-			if (queue_node_flags & SS_BACKGROUND) //update our running total
+			if (bg_calc) //update our running total
 				queue_priority_count_bg -= queue_node_priority
 			else
 				queue_priority_count -= queue_node_priority
@@ -582,6 +590,10 @@ GLOBAL_REAL(Master, /datum/controller/master) = new
 	log_world("MC: SoftReset: Finished.")
 	. = 1
 
+/// Warns us that the end of tick byond map_update will be laggier then normal, so that we can just skip running subsystems this tick.
+/datum/controller/master/proc/laggy_byond_map_update_incoming()
+	if (!skip_ticks)
+		skip_ticks = 1
 
 
 /datum/controller/master/stat_entry(msg)

code/controllers/subsystem/air.dm

@@ -1,11 +1,3 @@
-#define SSAIR_PIPENETS 1
-#define SSAIR_ATMOSMACHINERY 2
-#define SSAIR_REACTQUEUE 3
-#define SSAIR_EXCITEDGROUPS 4
-#define SSAIR_HIGHPRESSURE 5
-#define SSAIR_HOTSPOTS 6
-#define SSAIR_SUPERCONDUCTIVITY 7
-
 SUBSYSTEM_DEF(air)
 	name = "Atmospherics"
 	init_order = INIT_ORDER_AIR
@@ -20,6 +12,7 @@ SUBSYSTEM_DEF(air)
 	var/cost_hotspots = 0
 	var/cost_superconductivity = 0
 	var/cost_pipenets = 0
+	var/cost_rebuilds = 0
 	var/cost_atmos_machinery = 0
 
 	var/list/excited_groups = list()
@@ -27,6 +20,7 @@ SUBSYSTEM_DEF(air)
 	var/list/turf_react_queue = list()
 	var/list/hotspots = list()
 	var/list/networks = list()
+	var/list/pipenets_needing_rebuilt = list()
 	var/list/obj/machinery/atmos_machinery = list()
 	var/list/pipe_init_dirs_cache = list()
 
@@ -39,7 +33,7 @@ SUBSYSTEM_DEF(air)
 
 
 	var/list/currentrun = list()
-	var/currentpart = SSAIR_PIPENETS
+	var/currentpart = SSAIR_REBUILD_PIPENETS
 
 	var/map_loading = TRUE
 	var/list/queued_for_activation
@@ -52,6 +46,7 @@ SUBSYSTEM_DEF(air)
 	msg += "HS:[round(cost_hotspots,1)]|"
 	msg += "SC:[round(cost_superconductivity,1)]|"
 	msg += "PN:[round(cost_pipenets,1)]|"
+	msg += "RB:[round(cost_rebuilds,1)]|"
 	msg += "AM:[round(cost_atmos_machinery,1)]"
 	msg += "} "
 	msg += "AT:[active_turfs.len]|"
@@ -77,6 +72,18 @@ SUBSYSTEM_DEF(air)
 /datum/controller/subsystem/air/fire(resumed = 0)
 	var/timer = TICK_USAGE_REAL
 
+	if(currentpart == SSAIR_REBUILD_PIPENETS)
+		var/list/pipenet_rebuilds = pipenets_needing_rebuilt
+		for(var/thing in pipenet_rebuilds)
+			var/obj/machinery/atmospherics/AT = thing
+			AT.build_network()
+		cost_rebuilds = MC_AVERAGE(cost_rebuilds, TICK_DELTA_TO_MS(TICK_USAGE_REAL - timer))
+		pipenets_needing_rebuilt.Cut()
+		if(state != SS_RUNNING)
+			return
+		resumed = FALSE
+		currentpart = SSAIR_PIPENETS
+
 	if(currentpart == SSAIR_PIPENETS || !resumed)
 		process_pipenets(resumed)
 		cost_pipenets = MC_AVERAGE(cost_pipenets, TICK_DELTA_TO_MS(TICK_USAGE_REAL - timer))
@@ -137,9 +144,7 @@ SUBSYSTEM_DEF(air)
 		if(state != SS_RUNNING)
 			return
 		resumed = 0
-	currentpart = SSAIR_PIPENETS
-
-
+	currentpart = SSAIR_REBUILD_PIPENETS
 
 /datum/controller/subsystem/air/proc/process_pipenets(resumed = 0)
 	if (!resumed)
@@ -156,6 +161,9 @@ SUBSYSTEM_DEF(air)
 		if(MC_TICK_CHECK)
 			return
 
+/datum/controller/subsystem/air/proc/add_to_rebuild_queue(atmos_machine)
+	if(istype(atmos_machine, /obj/machinery/atmospherics))
+		pipenets_needing_rebuilt += atmos_machine
 
 /datum/controller/subsystem/air/proc/process_atmos_machinery(resumed = 0)
 	var/seconds = wait * 0.1