[MIRROR] Experiment with holding hard references to objects being qdeleted in 515 (saves 1.1+ seconds on init times, more on prod) [MDB IGNORE] (#18361)

* Experiment with holding hard references to objects being qdeleted in 515 (saves 1.1+ seconds on init times, more on prod) (#72033)

## About The Pull Request
Adds `EXPERIMENT_515_QDEL_HARD_REFERENCE`, which will queue to the GC
subsystem using hard references rather than `\ref`. This is only
possible in 515 because of the new `refcount` proc. `\ref` is very very
slow and has some nasty knock on effects, so removing its usages where
possible is good.

This is an explicit opt in define because I want to give us the ability
to test 515 on live while only testing 515 itself, not our experimental
changes. We have a few more of these we want to do so I made a separate
file for them. They're auto-defined in unit tests so we see them with
the alternate test runner. In a perfect world we'd test both on and off,
but eh.

Closes https://github.com/tgstation/dev-cycles-initiative/issues/10

* Experiment with holding hard references to objects being qdeleted in 515 (saves 1.1+ seconds on init times, more on prod)

* fix missed underbarrels

* HEV radio

* Keeps gc_destroyed from getting updated on every step thru the gc queue. (#72401)

Keeps gc_destroyed from getting updated on every step thru the gc queue.

Fixes logic that assumed gc_destroyed is the time the object first
qdel'ed. it used to get updated on each stage of the garbage controller
and there are 3 stages.

Added list index defines for the inner gc item list.

* test fix

* final fix

Co-authored-by: Mothblocks <35135081+Mothblocks@users.noreply.github.com>
Co-authored-by: tastyfish <crazychris32@gmail.com>
Co-authored-by: Kyle Spier-Swenson <kyleshome@gmail.com>

code/controllers/subsystem/atoms.dm

@@ -22,6 +22,8 @@ SUBSYSTEM_DEF(atoms)
 	/// Atoms that will be deleted once the subsystem is initialized
 	var/list/queued_deletions = list()
 
+	var/init_start_time
+
 	#ifdef PROFILE_MAPLOAD_INIT_ATOM
 	var/list/mapload_init_times = list()
 	#endif
@@ -29,6 +31,7 @@ SUBSYSTEM_DEF(atoms)
 	initialized = INITIALIZATION_INSSATOMS
 
 /datum/controller/subsystem/atoms/Initialize()
+	init_start_time = world.time
 	setupGenetics() //to set the mutations' sequence
 
 	initialized = INITIALIZATION_INNEW_MAPLOAD
@@ -122,8 +125,11 @@ SUBSYSTEM_DEF(atoms)
 /// Init this specific atom
 /datum/controller/subsystem/atoms/proc/InitAtom(atom/A, from_template = FALSE, list/arguments)
 	var/the_type = A.type
+
 	if(QDELING(A))
-		BadInitializeCalls[the_type] |= BAD_INIT_QDEL_BEFORE
+		// Check init_start_time to not worry about atoms created before the atoms SS that are cleaned up before this
+		if (A.gc_destroyed > init_start_time)
+			BadInitializeCalls[the_type] |= BAD_INIT_QDEL_BEFORE
 		return TRUE
 
 	// This is handled and battle tested by dreamchecker. Limit to UNIT_TESTS just in case that ever fails.

code/controllers/subsystem/garbage.dm

@@ -139,6 +139,13 @@ SUBSYSTEM_DEF(garbage)
 			pass_counts[i] = 0
 			fail_counts[i] = 0
 
+#ifdef EXPERIMENT_515_QDEL_HARD_REFERENCE
+// 1 from the hard reference in the queue, and 1 from the variable used before this
+#define IS_DELETED(datum, _) (refcount(##datum) == 2)
+#else
+#define IS_DELETED(datum, gcd_at_time) (isnull(##datum) || ##datum.gc_destroyed != gcd_at_time)
+#endif
+
 /datum/controller/subsystem/garbage/proc/HandleQueue(level = GC_QUEUE_FILTER)
 	if (level == GC_QUEUE_FILTER)
 		delslasttick = 0
@@ -159,26 +166,32 @@ SUBSYSTEM_DEF(garbage)
 	//Normally this isn't expensive, but the gc queue can grow to 40k items, and that gets costly/causes overrun.
 	for (var/i in 1 to length(queue))
 		var/list/L = queue[i]
-		if (length(L) < 2)
+		if (length(L) < GC_QUEUE_ITEM_INDEX_COUNT)
 			count++
 			if (MC_TICK_CHECK)
 				return
 			continue
 
-		var/GCd_at_time = L[1]
-		if(GCd_at_time > cut_off_time)
+		var/queued_at_time = L[GC_QUEUE_ITEM_QUEUE_TIME]
+		var/GCd_at_time = L[GC_QUEUE_ITEM_GCD_DESTROYED]
+		if(queued_at_time > cut_off_time)
 			break // Everything else is newer, skip them
 		count++
-		var/refID = L[2]
+
+#ifdef EXPERIMENT_515_QDEL_HARD_REFERENCE
+		var/datum/D = L[GC_QUEUE_ITEM_REF]
+#else
+		var/refID = L[GC_QUEUE_ITEM_REF]
 		var/datum/D
 		D = locate(refID)
+#endif
 
-		if (!D || D.gc_destroyed != GCd_at_time) // So if something else coincidently gets the same ref, it's not deleted by mistake
+		if (IS_DELETED(D, GCd_at_time)) // So if something else coincidently gets the same ref, it's not deleted by mistake
 			++gcedlasttick
 			++totalgcs
 			pass_counts[level]++
 			#ifdef REFERENCE_TRACKING
-			reference_find_on_fail -= refID //It's deleted we don't care anymore.
+			reference_find_on_fail -= text_ref(D) //It's deleted we don't care anymore.
 			#endif
 			if (MC_TICK_CHECK)
 				return
@@ -194,7 +207,7 @@ SUBSYSTEM_DEF(garbage)
 		switch (level)
 			if (GC_QUEUE_CHECK)
 				#ifdef REFERENCE_TRACKING
-				if(reference_find_on_fail[refID])
+				if(reference_find_on_fail[text_ref(D)])
 					INVOKE_ASYNC(D, TYPE_PROC_REF(/datum,find_references))
 					ref_searching = TRUE
 				#ifdef GC_FAILURE_HARD_LOOKUP
@@ -202,12 +215,17 @@ SUBSYSTEM_DEF(garbage)
 					INVOKE_ASYNC(D, TYPE_PROC_REF(/datum,find_references))
 					ref_searching = TRUE
 				#endif
-				reference_find_on_fail -= refID
+				reference_find_on_fail -= text_ref(D)
 				#endif
 				var/type = D.type
 				var/datum/qdel_item/I = items[type]
 
-				log_world("## TESTING: GC: -- [text_ref(D)] | [type] was unable to be GC'd --")
+				var/message = "## TESTING: GC: -- [text_ref(D)] | [type] was unable to be GC'd --"
+#if DM_VERSION >= 515
+				message = "[message] (ref count of [refcount(D)])"
+#endif
+				log_world(message)
+
 				#ifdef TESTING
 				for(var/c in GLOB.admins) //Using testing() here would fill the logs with ADMIN_VV garbage
 					var/client/admin = c
@@ -242,19 +260,27 @@ SUBSYSTEM_DEF(garbage)
 		queue.Cut(1,count+1)
 		count = 0
 
+#undef IS_DELETED
+
 /datum/controller/subsystem/garbage/proc/Queue(datum/D, level = GC_QUEUE_FILTER)
 	if (isnull(D))
 		return
 	if (level > GC_QUEUE_COUNT)
 		HardDelete(D)
 		return
-	var/gctime = world.time
-	var/refid = text_ref(D)
+	var/queue_time = world.time
 
-	D.gc_destroyed = gctime
+#ifdef EXPERIMENT_515_QDEL_HARD_REFERENCE
+	var/refid = D
+#else
+	var/refid = text_ref(D)
+#endif
+	if (D.gc_destroyed <= 0)
+		D.gc_destroyed = queue_time
+	
 	var/list/queue = queues[level]
 
-	queue[++queue.len] = list(gctime, refid) // not += for byond reasons
+	queue[++queue.len] = list(queue_time, refid, D.gc_destroyed) // not += for byond reasons
 
 //this is mainly to separate things profile wise.
 /datum/controller/subsystem/garbage/proc/HardDelete(datum/D)