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dc684c60d1
The new behavior of disconnect to block the current thread until the disconnect succeeded is better than throwing it off to happen at some point
58 lines
3.3 KiB
Diff
58 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 f80cde264393f3606bc0c54ba2fd6a467f4bcb5a..c5e1040c239874dcf20b79472bf690ee7f0a9e5f 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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