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Firstly, the old methods all routed to the CompletableFuture method. However, the CF method could not guarantee that if the caller was off-main that the future would be "completed" on-main. Since the callback methods used the CF one, this meant that the callback methods did not guarantee that the callbacks were to be called on the main thread. Now, all methods route to getChunkAtAsync(x, z, gen, urgent, cb) so that the methods with the callback are guaranteed to invoke the callback on the main thread. The CF behavior remains unchanged; it may still appear to complete on main if invoked off-main. Secondly, remove the scheduleOnMain invocation in the async chunk completion. This unnecessarily delays the callback by 1 tick. Thirdly, add getChunksAtAsync(minX, minZ, maxX, maxZ, ...) which will load chunks within an area. This method is provided as a helper as keeping all chunks loaded within an area can be complicated to implement for plugins (due to the lacking ticket API), and is already implemented internally anyways. Fourthly, remove the ticket addition that occured with getChunkAt and getChunkAtAsync. The ticket addition may delay the unloading of the chunk unnecessarily. It also fixes a very rare timing bug where the future/callback would be completed after the chunk unloads.
57 lines
3.3 KiB
Diff
57 lines
3.3 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: stonar96 <minecraft.stonar96@gmail.com>
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Date: Sun, 17 Jan 2021 01:11:36 +0100
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Subject: [PATCH] Optimize HashMapPalette
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HashMapPalette uses an instance of CrudeIncrementalIntIdentityHashBiMap
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internally. A Palette has a preset maximum size = 1 << bits.
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CrudeIncrementalIntIdentityHashBiMap has an initial size but is
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automatically resized. The CrudeIncrementalIntIdentityHashBiMap is created
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with the maximum size in the constructor of HashMapPalette, with the aim
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that it doesn't need to be resized anymore. However, there are two things
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that I think Mojang hasn't considered here:
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1) The CrudeIncrementalIntIdentityHashBiMap is resized, when its initial
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size is reached and not the next time, when a further object is added.
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2) HashMapPalette adds objects (unnecessarily) before checking if the
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initial size of CrudeIncrementalIntIdentityHashBiMap is reached.
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This means to actually avoid resize operations in
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CrudeIncrementalIntIdentityHashBiMap, one has to add 2 to the initial size
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or add 1 and check the size before adding objects. This commit implements
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the second approach. Note that this isn't only an optimization but also
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makes async reads of Palettes fail-safe. An async read while the
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CrudeIncrementalIntIdentityHashBiMap is resized is fatal and can even lead
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to corrupted data. This is also something that Anti-Xray is currently
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relying on.
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diff --git a/src/main/java/net/minecraft/world/level/chunk/HashMapPalette.java b/src/main/java/net/minecraft/world/level/chunk/HashMapPalette.java
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index ac673cb38755852eef37e915f157f6a702117306..98dbeaf8bde15940e5b5d5d1f13fd4bb32f0a10d 100644
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--- a/src/main/java/net/minecraft/world/level/chunk/HashMapPalette.java
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+++ b/src/main/java/net/minecraft/world/level/chunk/HashMapPalette.java
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@@ -20,7 +20,7 @@ public class HashMapPalette<T> implements Palette<T> {
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}
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public HashMapPalette(IdMap<T> idList, int indexBits, PaletteResize<T> listener) {
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- this(idList, indexBits, listener, CrudeIncrementalIntIdentityHashBiMap.create(1 << indexBits));
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+ this(idList, indexBits, listener, CrudeIncrementalIntIdentityHashBiMap.create((1 << indexBits) + 1)); // Paper - Perf: Avoid unnecessary resize operation in CrudeIncrementalIntIdentityHashBiMap
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}
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private HashMapPalette(IdMap<T> idList, int indexBits, PaletteResize<T> listener, CrudeIncrementalIntIdentityHashBiMap<T> map) {
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@@ -38,10 +38,16 @@ public class HashMapPalette<T> implements Palette<T> {
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public int idFor(T object) {
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int i = this.values.getId(object);
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if (i == -1) {
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- i = this.values.add(object);
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- if (i >= 1 << this.bits) {
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+ // Paper start - Perf: Avoid unnecessary resize operation in CrudeIncrementalIntIdentityHashBiMap and optimize
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+ // We use size() instead of the result from add(K)
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+ // This avoids adding another object unnecessarily
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+ // Without this change, + 2 would be required in the constructor
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+ if (this.values.size() >= 1 << this.bits) {
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i = this.resizeHandler.onResize(this.bits + 1, object);
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+ } else {
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+ i = this.values.add(object);
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}
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+ // Paper end - Perf: Avoid unnecessary resize operation in CrudeIncrementalIntIdentityHashBiMap and optimize
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}
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return i;
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