Paper/patches/server/0516-Significantly-improve-performance-of-the-end-generat.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

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: SuperCoder7979 <25208576+SuperCoder7979@users.noreply.github.com>
Date: Tue, 3 Nov 2020 23:48:05 -0600
Subject: [PATCH] Significantly improve performance of the end generation
This patch implements a noise cache for the end which significantly reduces the computation time of generation. This results in about a 3x improvement.
Original code by SuperCoder7979 and Gegy in Lithium, licensed under LGPL-3.0 (Source: https://github.com/jellysquid3/lithium-fabric)
Co-authored-by: Gegy <gegy1000@gmail.com>
Co-authored-by: Dylan Xaldin <Puremin0rez515@gmail.com>
Co-authored-by: pop4959 <pop4959@gmail.com>
diff --git a/src/main/java/net/minecraft/world/level/levelgen/DensityFunctions.java b/src/main/java/net/minecraft/world/level/levelgen/DensityFunctions.java
index 683474cd96d3a0cdfb3b22d0111c8d3231f01d92..f09fd5027535d2fc4d4afae010f08e7accff45b3 100644
--- a/src/main/java/net/minecraft/world/level/levelgen/DensityFunctions.java
+++ b/src/main/java/net/minecraft/world/level/levelgen/DensityFunctions.java
@@ -489,6 +489,16 @@ public final class DensityFunctions {
public static final KeyDispatchDataCodec<DensityFunctions.EndIslandDensityFunction> CODEC = KeyDispatchDataCodec.of(MapCodec.unit(new DensityFunctions.EndIslandDensityFunction(0L)));
private static final float ISLAND_THRESHOLD = -0.9F;
private final SimplexNoise islandNoise;
+ // Paper start
+ private static final class NoiseCache {
+ public long[] keys = new long[8192];
+ public float[] values = new float[8192];
+ public NoiseCache() {
+ java.util.Arrays.fill(keys, Long.MIN_VALUE);
+ }
+ }
+ private static final ThreadLocal<java.util.Map<SimplexNoise, NoiseCache>> noiseCache = ThreadLocal.withInitial(java.util.WeakHashMap::new);
+ // Paper end
public EndIslandDensityFunction(long seed) {
RandomSource randomSource = new LegacyRandomSource(seed);
@@ -504,12 +514,26 @@ public final class DensityFunctions {
float f = 100.0F - Mth.sqrt((long) x * (long) x + (long) z * (long) z) * 8.0F; // Paper - cast ints to long to avoid integer overflow
f = Mth.clamp(f, -100.0F, 80.0F);
+ NoiseCache cache = noiseCache.get().computeIfAbsent(sampler, noiseKey -> new NoiseCache()); // Paper
for(int m = -12; m <= 12; ++m) {
for(int n = -12; n <= 12; ++n) {
long o = (long)(i + m);
long p = (long)(j + n);
- if (o * o + p * p > 4096L && sampler.getValue((double)o, (double)p) < (double)-0.9F) {
- float g = (Mth.abs((float)o) * 3439.0F + Mth.abs((float)p) * 147.0F) % 13.0F + 9.0F;
+ // Paper start - Significantly improve end generation performance by using a noise cache
+ long key = net.minecraft.world.level.ChunkPos.asLong((int) o, (int) p);
+ int index = (int) it.unimi.dsi.fastutil.HashCommon.mix(key) & 8191;
+ float g = Float.MIN_VALUE;
+ if (cache.keys[index] == key) {
+ g = cache.values[index];
+ } else {
+ if (o * o + p * p > 4096L && sampler.getValue((double)o, (double)p) < (double)-0.9F) {
+ g = (Mth.abs((float) o) * 3439.0F + Mth.abs((float) p) * 147.0F) % 13.0F + 9.0F;
+ }
+ cache.keys[index] = key;
+ cache.values[index] = g;
+ }
+ if (g != Float.MIN_VALUE) {
+ // Paper end
float h = (float)(k - m * 2);
float q = (float)(l - n * 2);
float r = 100.0F - Mth.sqrt(h * h + q * q) * g;