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Paper/patches/removed/1.19.2-legacy-chunksystem/0845-Replace-ticket-level-propagator.patch
Spottedleaf 01a13871de
Rewrite chunk system (#8177)
Patch documentation to come

Issues with the old system that are fixed now:
- World generation does not scale with cpu cores effectively.
- Relies on the main thread for scheduling and maintaining chunk state, dropping chunk load/generate rates at lower tps.
- Unreliable prioritisation of chunk gen/load calls that block the main thread.
- Shutdown logic is utterly unreliable, as it has to wait for all chunks to unload - is it guaranteed that the chunk system is in a state on shutdown that it can reliably do this? Watchdog shutdown also typically failed due to thread checks, which is now resolved.
- Saving of data is not unified (i.e can save chunk data without saving entity data, poses problems for desync if shutdown is really abnormal.
- Entities are not loaded with chunks. This caused quite a bit of headache for Chunk#getEntities API, but now the new chunk system loads entities with chunks so that they are ready whenever the chunk loads in. Effectively brings the behavior back to 1.16 era, but still storing entities in their own separate regionfiles.

The above list is not complete. The patch documentation will complete it.

New chunk system hard relies on starlight and dataconverter, and most importantly the new concurrent utilities in ConcurrentUtil.

Some of the old async chunk i/o interface (i.e the old file io thread reroutes _some_ calls to the new file io thread) is kept for plugin compat reasons. It will be removed in the next major version of minecraft.

The old legacy chunk system patches have been moved to the removed folder in case we need them again.
2022-09-26 01:02:51 -07:00

259 Zeilen
13 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sun, 21 Mar 2021 16:25:42 -0700
Subject: [PATCH] Replace ticket level propagator
Mojang's propagator is slow, and this isn't surprising
given it's built on the same utilities the vanilla light engine
is built on. The simple propagator I wrote is approximately 4x
faster when simulating player movement. For a long time timing
reports have shown this function take up significant tick, (
approx 10% or more), and async sampling data shows the level
propagation alone takes up a significant amount. So this
should help with that. A big side effect is that mid-tick
will be more effective, since more time will be allocated
to actually processing chunk tasks vs the ticket level updates.
diff --git a/src/main/java/net/minecraft/server/level/DistanceManager.java b/src/main/java/net/minecraft/server/level/DistanceManager.java
index 06e4d3a02e0d1326b7029157856476db4ef3575e..f581a9f79b2357118d912a15344ff94df3b0c50e 100644
--- a/src/main/java/net/minecraft/server/level/DistanceManager.java
+++ b/src/main/java/net/minecraft/server/level/DistanceManager.java
@@ -38,6 +38,7 @@ import net.minecraft.world.level.chunk.ChunkStatus;
import net.minecraft.world.level.chunk.LevelChunk;
import org.slf4j.Logger;
+import it.unimi.dsi.fastutil.longs.Long2IntLinkedOpenHashMap; // Paper
public abstract class DistanceManager {
static final Logger LOGGER = LogUtils.getLogger();
@@ -48,7 +49,7 @@ public abstract class DistanceManager {
private static final int BLOCK_TICKING_LEVEL_THRESHOLD = 33;
final Long2ObjectMap<ObjectSet<ServerPlayer>> playersPerChunk = new Long2ObjectOpenHashMap();
public final Long2ObjectOpenHashMap<SortedArraySet<Ticket<?>>> tickets = new Long2ObjectOpenHashMap();
- private final DistanceManager.ChunkTicketTracker ticketTracker = new DistanceManager.ChunkTicketTracker();
+ //private final DistanceManager.ChunkTicketTracker ticketTracker = new DistanceManager.ChunkTicketTracker(); // Paper - replace ticket level propagator
public static final int MOB_SPAWN_RANGE = 8; // private final ChunkMapDistance.b f = new ChunkMapDistance.b(8); // Paper - no longer used
private final TickingTracker tickingTicketsTracker = new TickingTracker();
private final DistanceManager.PlayerTicketTracker playerTicketManager = new DistanceManager.PlayerTicketTracker(33);
@@ -83,6 +84,46 @@ public abstract class DistanceManager {
this.chunkMap = chunkMap; // Paper
}
+ // Paper start - replace ticket level propagator
+ protected final Long2IntLinkedOpenHashMap ticketLevelUpdates = new Long2IntLinkedOpenHashMap() {
+ @Override
+ protected void rehash(int newN) {
+ // no downsizing allowed
+ if (newN < this.n) {
+ return;
+ }
+ super.rehash(newN);
+ }
+ };
+ protected final io.papermc.paper.util.misc.Delayed8WayDistancePropagator2D ticketLevelPropagator = new io.papermc.paper.util.misc.Delayed8WayDistancePropagator2D(
+ (long coordinate, byte oldLevel, byte newLevel) -> {
+ DistanceManager.this.ticketLevelUpdates.putAndMoveToLast(coordinate, convertBetweenTicketLevels(newLevel));
+ }
+ );
+ // function for converting between ticket levels and propagator levels and vice versa
+ // the problem is the ticket level propagator will propagate from a set source down to zero, whereas mojang expects
+ // levels to propagate from a set value up to a maximum value. so we need to convert the levels we put into the propagator
+ // and the levels we get out of the propagator
+
+ // this maps so that GOLDEN_TICKET + 1 will be 0 in the propagator, GOLDEN_TICKET will be 1, and so on
+ // we need GOLDEN_TICKET+1 as 0 because anything >= GOLDEN_TICKET+1 should be unloaded
+ public static int convertBetweenTicketLevels(final int level) {
+ return ChunkMap.MAX_CHUNK_DISTANCE - level + 1;
+ }
+
+ protected final int getPropagatedTicketLevel(final long coordinate) {
+ return convertBetweenTicketLevels(this.ticketLevelPropagator.getLevel(coordinate));
+ }
+
+ protected final void updateTicketLevel(final long coordinate, final int ticketLevel) {
+ if (ticketLevel > ChunkMap.MAX_CHUNK_DISTANCE) {
+ this.ticketLevelPropagator.removeSource(coordinate);
+ } else {
+ this.ticketLevelPropagator.setSource(coordinate, convertBetweenTicketLevels(ticketLevel));
+ }
+ }
+ // Paper end - replace ticket level propagator
+
protected void purgeStaleTickets() {
++this.ticketTickCounter;
ObjectIterator objectiterator = this.tickets.long2ObjectEntrySet().fastIterator();
@@ -117,7 +158,7 @@ public abstract class DistanceManager {
}
if (flag) {
- this.ticketTracker.update(entry.getLongKey(), DistanceManager.getTicketLevelAt((SortedArraySet) entry.getValue()), false);
+ this.updateTicketLevel(entry.getLongKey(), getTicketLevelAt(entry.getValue())); // Paper - replace ticket level propagator
}
if (((SortedArraySet) entry.getValue()).isEmpty()) {
@@ -140,61 +181,94 @@ public abstract class DistanceManager {
@Nullable
protected abstract ChunkHolder updateChunkScheduling(long pos, int level, @Nullable ChunkHolder holder, int k);
+ protected long ticketLevelUpdateCount; // Paper - replace ticket level propagator
public boolean runAllUpdates(ChunkMap chunkStorage) {
//this.f.a(); // Paper - no longer used
this.tickingTicketsTracker.runAllUpdates();
org.spigotmc.AsyncCatcher.catchOp("DistanceManagerTick"); // Paper
this.playerTicketManager.runAllUpdates();
- int i = Integer.MAX_VALUE - this.ticketTracker.runDistanceUpdates(Integer.MAX_VALUE);
- boolean flag = i != 0;
+ boolean flag = this.ticketLevelPropagator.propagateUpdates(); // Paper - replace ticket level propagator
if (flag) {
;
}
- // Paper start
- if (!this.pendingChunkUpdates.isEmpty()) {
- this.pollingPendingChunkUpdates = true; try { // Paper - Chunk priority
- while(!this.pendingChunkUpdates.isEmpty()) {
- ChunkHolder remove = this.pendingChunkUpdates.remove();
- remove.isUpdateQueued = false;
- remove.updateFutures(chunkStorage, this.mainThreadExecutor);
- }
- } finally { this.pollingPendingChunkUpdates = false; } // Paper - Chunk priority
- // Paper end
- return true;
- } else {
- if (!this.ticketsToRelease.isEmpty()) {
- LongIterator longiterator = this.ticketsToRelease.iterator();
+ // Paper start - replace level propagator
+ ticket_update_loop:
+ while (!this.ticketLevelUpdates.isEmpty()) {
+ flag = true;
- while (longiterator.hasNext()) {
- long j = longiterator.nextLong();
+ boolean oldPolling = this.pollingPendingChunkUpdates;
+ this.pollingPendingChunkUpdates = true;
+ try {
+ for (java.util.Iterator<Long2IntMap.Entry> iterator = this.ticketLevelUpdates.long2IntEntrySet().fastIterator(); iterator.hasNext();) {
+ Long2IntMap.Entry entry = iterator.next();
+ long key = entry.getLongKey();
+ int newLevel = entry.getIntValue();
+ ChunkHolder chunk = this.getChunk(key);
+
+ if (chunk == null && newLevel > ChunkMap.MAX_CHUNK_DISTANCE) {
+ // not loaded and it shouldn't be loaded!
+ continue;
+ }
- if (this.getTickets(j).stream().anyMatch((ticket) -> {
- return ticket.getType() == TicketType.PLAYER;
- })) {
- ChunkHolder playerchunk = chunkStorage.getUpdatingChunkIfPresent(j);
+ int currentLevel = chunk == null ? ChunkMap.MAX_CHUNK_DISTANCE + 1 : chunk.getTicketLevel();
- if (playerchunk == null) {
- throw new IllegalStateException();
+ if (currentLevel == newLevel) {
+ // nothing to do
+ continue;
+ }
+
+ this.updateChunkScheduling(key, newLevel, chunk, currentLevel);
+ }
+
+ long recursiveCheck = ++this.ticketLevelUpdateCount;
+ while (!this.ticketLevelUpdates.isEmpty()) {
+ long key = this.ticketLevelUpdates.firstLongKey();
+ int newLevel = this.ticketLevelUpdates.removeFirstInt();
+ ChunkHolder chunk = this.getChunk(key);
+
+ if (chunk == null) {
+ if (newLevel <= ChunkMap.MAX_CHUNK_DISTANCE) {
+ throw new IllegalStateException("Expected chunk holder to be created");
}
+ // not loaded and it shouldn't be loaded!
+ continue;
+ }
- CompletableFuture<Either<LevelChunk, ChunkHolder.ChunkLoadingFailure>> completablefuture = playerchunk.getEntityTickingChunkFuture();
+ int currentLevel = chunk.oldTicketLevel;
- completablefuture.thenAccept((either) -> {
- this.mainThreadExecutor.execute(() -> {
- this.ticketThrottlerReleaser.tell(ChunkTaskPriorityQueueSorter.release(() -> {
- }, j, false));
- });
- });
+ if (currentLevel == newLevel) {
+ // nothing to do
+ continue;
+ }
+
+ chunk.updateFutures(chunkStorage, this.mainThreadExecutor);
+ if (recursiveCheck != this.ticketLevelUpdateCount) {
+ // back to the start, we must create player chunks and update the ticket level fields before
+ // processing the actual level updates
+ continue ticket_update_loop;
}
}
- this.ticketsToRelease.clear();
- }
+ for (;;) {
+ if (recursiveCheck != this.ticketLevelUpdateCount) {
+ continue ticket_update_loop;
+ }
+ ChunkHolder pendingUpdate = this.pendingChunkUpdates.poll();
+ if (pendingUpdate == null) {
+ break;
+ }
- return flag;
+ pendingUpdate.updateFutures(chunkStorage, this.mainThreadExecutor);
+ }
+ } finally {
+ this.pollingPendingChunkUpdates = oldPolling;
+ }
}
+
+ return flag;
+ // Paper end - replace level propagator
}
boolean pollingPendingChunkUpdates = false; // Paper - Chunk priority
@@ -206,7 +280,7 @@ public abstract class DistanceManager {
ticket1.setCreatedTick(this.ticketTickCounter);
if (ticket.getTicketLevel() < j) {
- this.ticketTracker.update(i, ticket.getTicketLevel(), true);
+ this.updateTicketLevel(i, ticket.getTicketLevel()); // Paper - replace ticket level propagator
}
return ticket == ticket1; // CraftBukkit
@@ -250,7 +324,7 @@ public abstract class DistanceManager {
// Paper start - Chunk priority
int newLevel = getTicketLevelAt(arraysetsorted);
if (newLevel > oldLevel) {
- this.ticketTracker.update(i, newLevel, false);
+ this.updateTicketLevel(i, newLevel); // Paper // Paper - replace ticket level propagator
}
// Paper end
return removed; // CraftBukkit
@@ -564,7 +638,7 @@ public abstract class DistanceManager {
}
if (flag) {
- this.ticketTracker.update(entry.getLongKey(), DistanceManager.getTicketLevelAt((SortedArraySet) entry.getValue()), false);
+ this.updateTicketLevel(entry.getLongKey(), DistanceManager.getTicketLevelAt((SortedArraySet) entry.getValue())); // Paper - replace ticket level propagator
}
if (((SortedArraySet) entry.getValue()).isEmpty()) {
@@ -587,7 +661,7 @@ public abstract class DistanceManager {
SortedArraySet<Ticket<?>> tickets = entry.getValue();
if (tickets.remove(target)) {
// copied from removeTicket
- this.ticketTracker.update(entry.getLongKey(), DistanceManager.getTicketLevelAt(tickets), false);
+ this.updateTicketLevel(entry.getLongKey(), getTicketLevelAt(tickets)); // Paper - replace ticket level propagator
// can't use entry after it's removed
if (tickets.isEmpty()) {