Well, that works

code/__DEFINES/_tick.dm

@@ -1,7 +1,11 @@
 /// Percentage of tick to leave for master controller to run
 #define MAPTICK_MC_MIN_RESERVE 70
 /// internal_tick_usage is updated every tick by extools
+#if DM_VERSION > 513
 #define MAPTICK_LAST_INTERNAL_TICK_USAGE world.map_cpu
+#else
+#define MAPTICK_LAST_INTERNAL_TICK_USAGE 50
+#endif
 /// Tick limit while running normally
 #define TICK_BYOND_RESERVE 2
 #define TICK_LIMIT_RUNNING (max(100 - TICK_BYOND_RESERVE - MAPTICK_LAST_INTERNAL_TICK_USAGE, MAPTICK_MC_MIN_RESERVE))

code/controllers/subsystem/air.dm

@@ -17,6 +17,8 @@ SUBSYSTEM_DEF(air)
 	var/cost_rebuilds = 0
 	var/cost_atmos_machinery = 0
 	var/cost_equalize = 0
+	var/thread_wait_ticks = 0
+	var/cur_thread_wait_ticks = 0
 
 	var/list/hotspots = list()
 	var/list/networks = list()
@@ -57,7 +59,7 @@ SUBSYSTEM_DEF(air)
 /datum/controller/subsystem/air/stat_entry(msg)
 	msg += "C:{"
 	msg += "AT:[round(cost_turfs,1)]|"
-	msg += "TH:[round(turf_process_time(),1)]|"
+	msg += "TH:[round(turf_process_time(),1)],[thread_wait_ticks]|"
 	msg += "EG:[round(cost_groups,1)]|"
 	msg += "EQ:[round(cost_equalize,1)]|"
 	msg += "PO:[round(cost_post_process,1)]|"
@@ -71,7 +73,7 @@ SUBSYSTEM_DEF(air)
 	msg += "HS:[hotspots.len]|"
 	msg += "PN:[networks.len]|"
 	msg += "HP:[high_pressure_delta.len]|"
-	msg += "DF:[max_deferred_airs]"
+	msg += "DF:[max_deferred_airs]|"
 	msg += "GA:[get_amt_gas_mixes()]|"
 	msg += "MG:[get_max_gas_mixes()]|"
 	return ..()
@@ -142,8 +144,11 @@ SUBSYSTEM_DEF(air)
 	if(currentpart == SSAIR_FINALIZE_TURFS)
 		finish_turf_processing(resumed)
 		if(state != SS_RUNNING)
+			cur_thread_wait_ticks++
 			return
 		resumed = 0
+		thread_wait_ticks = MC_AVERAGE(thread_wait_ticks, cur_thread_wait_ticks)
+		cur_thread_wait_ticks = 0
 		currentpart = SSAIR_DEFERRED_AIRS
 	if(currentpart == SSAIR_DEFERRED_AIRS)
 		timer = TICK_USAGE_REAL

code/controllers/subsystem/callback.dm

@@ -4,11 +4,11 @@ SUBSYSTEM_DEF(callbacks)
 	wait = 1
 	priority = FIRE_PRIORITY_CALLBACKS
 
-/proc/process_callbacks()
+/proc/process_atmos_callbacks()
 	SScallbacks.can_fire = 0
 	SScallbacks.flags |= SS_NO_FIRE
 	CRASH("Auxtools not found! Callback subsystem shutting itself off.")
 
 /datum/controller/subsystem/callbacks/fire()
-	if(process_callbacks(null,MC_TICK_REMAINING_MS))
+	if(process_atmos_callbacks(MC_TICK_REMAINING_MS))
 		pause()

code/game/world.dm

@@ -356,7 +356,7 @@ GLOBAL_LIST(topic_status_cache)
 	SSidlenpcpool.MaxZChanged()
 	world.refresh_atmos_grid()
 
-/// Extools atmos
+/// Auxtools atmos
 /world/proc/refresh_atmos_grid()
 
 /world/proc/change_fps(new_value = 20)

code/modules/atmospherics/environmental/LINDA_system.dm

@@ -58,11 +58,11 @@
 			if (T.atmos_adjacent_turfs)
 				T.atmos_adjacent_turfs -= src
 			UNSETEMPTY(T.atmos_adjacent_turfs)
-			T.set_sleeping(!length(T.atmos_adjacent_turfs))
+			T.set_sleeping(T.blocks_air)
 		T.__update_auxtools_turf_adjacency_info(isspaceturf(T.get_z_base_turf()), -1)
 	UNSETEMPTY(atmos_adjacent_turfs)
 	src.atmos_adjacent_turfs = atmos_adjacent_turfs
-	set_sleeping(!length(atmos_adjacent_turfs))
+	set_sleeping(blocks_air)
 	__update_auxtools_turf_adjacency_info(isspaceturf(get_z_base_turf()))
 
 /turf/proc/set_sleeping(should_sleep)

code/modules/atmospherics/gasmixtures/gas_mixture.dm

@@ -332,6 +332,11 @@ GLOBAL_LIST_INIT(auxtools_atmos_initialized,FALSE)
 /datum/gas_mixture/proc/get_true_breath_pressure(partial_pressure)
 	return (partial_pressure * BREATH_VOLUME) / (R_IDEAL_GAS_EQUATION * return_temperature())
 
+/datum/gas_mixture/proc/set_analyzer_results(instability)
+	if(!analyzer_results)
+		analyzer_results = new
+	analyzer_results["fusion"] = instability
+
 //Mathematical proofs:
 /*
 get_breath_partial_pressure(gas_pp) --> gas_pp/total_moles()*breath_pp = pp

code/modules/atmospherics/gasmixtures/reactions.dm

@@ -88,6 +88,18 @@
 		/datum/gas/oxygen = MINIMUM_MOLE_COUNT
 	)
 
+/proc/fire_expose(turf/open/location, datum/gas_mixture/air, temperature)
+	if(istype(location) && temperature > FIRE_MINIMUM_TEMPERATURE_TO_EXIST)
+		location.hotspot_expose(temperature, CELL_VOLUME)
+		for(var/I in location)
+			var/atom/movable/item = I
+			item.temperature_expose(air, temperature, CELL_VOLUME)
+		location.temperature_expose(air, temperature, CELL_VOLUME)
+
+/proc/radiation_burn(turf/open/location, energy_released)
+	if(location && prob(10))
+		radiation_pulse(location, energy_released/TRITIUM_BURN_RADIOACTIVITY_FACTOR)
+
 /datum/gas_reaction/tritfire/react(datum/gas_mixture/air, datum/holder)
 	var/energy_released = 0
 	var/old_heat_capacity = air.heat_capacity()
@@ -241,6 +253,20 @@
 //Fusion Rework Counter: Please increment this if you make a major overhaul to this system again.
 //6 reworks
 
+/proc/fusion_ball(datum/holder, reaction_energy, instability)
+	var/turf/open/location
+	if (istype(holder,/datum/pipeline)) //Find the tile the reaction is occuring on, or a random part of the network if it's a pipenet.
+		var/datum/pipeline/fusion_pipenet = holder
+		location = get_turf(pick(fusion_pipenet.members))
+	else
+		location = get_turf(holder)
+	if(location)
+		var/particle_chance = ((PARTICLE_CHANCE_CONSTANT)/(reaction_energy-PARTICLE_CHANCE_CONSTANT)) + 1//Asymptopically approaches 100% as the energy of the reaction goes up.
+		if(prob(PERCENT(particle_chance)))
+			location.fire_nuclear_particle()
+		var/rad_power = max((FUSION_RAD_COEFFICIENT/instability) + FUSION_RAD_MAX,0)
+		radiation_pulse(location,rad_power)
+
 /datum/gas_reaction/fusion
 	exclude = FALSE
 	priority = 2

tgstation.dme

@@ -312,8 +312,8 @@
 #include "code\controllers\subsystem\augury.dm"
 #include "code\controllers\subsystem\autotransfer.dm"
 #include "code\controllers\subsystem\blackbox.dm"
-#include "code\controllers\subsystem\callback.dm"
 #include "code\controllers\subsystem\blackmarket.dm"
+#include "code\controllers\subsystem\callback.dm"
 #include "code\controllers\subsystem\chat.dm"
 #include "code\controllers\subsystem\communications.dm"
 #include "code\controllers\subsystem\dbcore.dm"