oh fucking boy

code/__DEFINES/atmospherics.dm

@@ -16,6 +16,9 @@
 #define T0C						273.15	// 0degC
 #define T20C					293.15	// 20degC
 
+//Quantization
+#define ATMOS_QUANTIZATION_ACCURACY 0.0000001	//gases below this in mols are GC'd
+
 #define MOLES_CELLSTANDARD		(ONE_ATMOSPHERE*CELL_VOLUME/(T20C*R_IDEAL_GAS_EQUATION))	//moles in a 2.5 m^3 cell at 101.325 Pa and 20 degC
 #define M_CELL_WITH_RATIO		(MOLES_CELLSTANDARD * 0.005) //compared against for superconductivity
 #define O2STANDARD				0.21	//percentage of oxygen in a normal mixture of air
@@ -255,7 +258,7 @@
 
 //HELPERS
 #define THERMAL_ENERGY(gas) (gas.temperature * gas.heat_capacity())
-#define QUANTIZE(variable)		(round(variable,0.0000001))/*I feel the need to document what happens here. Basically this is used to catch most rounding errors, however it's previous value made it so that
+#define QUANTIZE(variable)		(round(variable,ATMOS_QUANTIZATION_ACCURACY))/*I feel the need to document what happens here. Basically this is used to catch most rounding errors, however it's previous value made it so that
 															once gases got hot enough, most procedures wouldnt occur due to the fact that the mole counts would get rounded away. Thus, we lowered it a few orders of magnititude */
 
 //prefer this to gas_mixture/total_moles in performance critical areas

code/modules/atmospherics/environmental/LINDA_turf_tile.dm

@@ -90,6 +90,7 @@
 
 /turf/open/archive()
 	ARCHIVE_TEMPERATURE(air)
+	air.gases_archived = air.gases.Copy()
 	archived_cycle = SSair.times_fired
 	temperature_archived = temperature
 

code/modules/atmospherics/gasmixtures/gas_mixture.dm

@@ -15,15 +15,16 @@ GLOBAL_LIST_INIT(meta_gas_overlays, meta_gas_overlay_list())
 GLOBAL_LIST_INIT(meta_gas_dangers, meta_gas_danger_list())
 GLOBAL_LIST_INIT(meta_gas_ids, meta_gas_id_list())
 GLOBAL_LIST_INIT(meta_gas_fusions, meta_gas_fusion_list())
+
 /datum/gas_mixture
 	var/list/gases = list()
+	var/tmp/list/gases_archived = list()
 	var/temperature = 0 //kelvins
 	var/tmp/temperature_archived = 0
 	var/volume = CELL_VOLUME //liters
 	var/last_share = 0
 	var/list/reaction_results = list()
 	var/list/analyzer_results //used for analyzer feedback - not initialized until its used
-	var/gc_share = FALSE // Whether to call garbage_collect() on the sharer during shares, used for immutable mixtures
 
 /datum/gas_mixture/New(volume)
 	if (!isnull(volume))
@@ -219,7 +220,7 @@ GLOBAL_LIST_INIT(meta_gas_fusions, meta_gas_fusion_list())
 
 /datum/gas_mixture/share(datum/gas_mixture/sharer, atmos_adjacent_turfs = 4)
 
-	var/list/cached_gases = gases
+	var/list/cached_gases = gases_archived
 	var/list/sharer_gases = sharer.gases
 
 	var/temperature_delta = temperature_archived - sharer.temperature_archived
@@ -242,10 +243,28 @@ GLOBAL_LIST_INIT(meta_gas_fusions, meta_gas_fusion_list())
 	var/gas_heat_capacity
 	//and also cache this shit rq because that results in sanic speed for reasons byond explanation
 	var/list/cached_gasheats = GLOB.meta_gas_specific_heats
+
+	//Do this early and save doing TWO MORE (probable) LIST ACCESSES!!
+	var/our_moles
+	var/their_moles
+
+	//decs are expensive
+	var/us
+	var/them
+
 	//GAS TRANSFER
 	for(var/id in cached_gases | sharer_gases) // transfer gases
+		us = cached_gases[id]
+		them = sharer_gases[id]
 
-		delta = QUANTIZE(cached_gases[id] - sharer_gases[id])/(atmos_adjacent_turfs+1) //the amount of gas that gets moved between the mixtures
+		//buitl in garbage collect
+		if(max(us, them) <= ATMOS_QUANTIZATION_ACCURACY)
+			cached_gases -= id
+			sharer_gases -= id
+			continue
+
+		delta = QUANTIZE(us - them)/(atmos_adjacent_turfs+1) //the amount of gas that gets moved between the mixtures
+		our_moles += cached
 
 		if(delta && abs_temperature_delta > MINIMUM_TEMPERATURE_DELTA_TO_CONSIDER)
 			gas_heat_capacity = delta * cached_gasheats[id]
@@ -259,6 +278,9 @@ GLOBAL_LIST_INIT(meta_gas_fusions, meta_gas_fusion_list())
 		moved_moles			+= delta
 		abs_moved_moles		+= abs(delta)
 
+		our_moles += cached_gases[id]
+		their_moles += sharer_gases[id]
+
 	last_share = abs_moved_moles
 
 	//THERMAL ENERGY TRANSFER
@@ -278,13 +300,7 @@ GLOBAL_LIST_INIT(meta_gas_fusions, meta_gas_fusion_list())
 				if(abs(new_sharer_heat_capacity/old_sharer_heat_capacity - 1) < 0.1) // <10% change in sharer heat capacity
 					temperature_share(sharer, OPEN_HEAT_TRANSFER_COEFFICIENT)
 
-	if (initial(sharer.gc_share))
-		GAS_GARBAGE_COLLECT(sharer.gases)
 	if(temperature_delta > MINIMUM_TEMPERATURE_TO_MOVE || abs(moved_moles) > MINIMUM_MOLES_DELTA_TO_MOVE)
-		var/our_moles
-		TOTAL_MOLES(cached_gases,our_moles)
-		var/their_moles
-		TOTAL_MOLES(sharer_gases,their_moles)
 		return (temperature_archived*(our_moles + moved_moles) - sharer.temperature_archived*(their_moles - moved_moles)) * R_IDEAL_GAS_EQUATION / volume
 
 /datum/gas_mixture/temperature_share(datum/gas_mixture/sharer, conduction_coefficient, sharer_temperature, sharer_heat_capacity)

code/modules/atmospherics/gasmixtures/immutable_mixtures.dm

@@ -3,7 +3,6 @@
 
 /datum/gas_mixture/immutable
 	var/initial_temperature
-	gc_share = TRUE
 
 /datum/gas_mixture/immutable/New()
 	..()