Paper/patches/server/0381-Reduce-Either-Optional-allocation.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: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Mon, 6 Apr 2020 18:35:09 -0700
Subject: [PATCH] Reduce Either Optional allocation
In order to get chunk values, we shouldn't need to create
an optional each time.
diff --git a/src/main/java/com/mojang/datafixers/util/Either.java b/src/main/java/com/mojang/datafixers/util/Either.java
index a90adac7bd7ebd423f480e9ae0f44cb9d521fa4f..3f65fe71024928e35111fc6719a290aab9a6859e 100644
--- a/src/main/java/com/mojang/datafixers/util/Either.java
+++ b/src/main/java/com/mojang/datafixers/util/Either.java
@@ -22,7 +22,7 @@ public abstract class Either<L, R> implements App<Either.Mu<R>, L> {
}
private static final class Left<L, R> extends Either<L, R> {
- private final L value;
+ private final L value; private Optional<L> valueOptional; // Paper - reduce the optional allocation...
public Left(final L value) {
this.value = value;
@@ -51,7 +51,7 @@ public abstract class Either<L, R> implements App<Either.Mu<R>, L> {
@Override
public Optional<L> left() {
- return Optional.of(value);
+ return this.valueOptional == null ? this.valueOptional = Optional.of(this.value) : this.valueOptional; // Paper - reduce the optional allocation...
}
@Override
@@ -83,7 +83,7 @@ public abstract class Either<L, R> implements App<Either.Mu<R>, L> {
}
private static final class Right<L, R> extends Either<L, R> {
- private final R value;
+ private final R value; private Optional<R> valueOptional; // Paper - reduce the optional allocation...
public Right(final R value) {
this.value = value;
@@ -117,7 +117,7 @@ public abstract class Either<L, R> implements App<Either.Mu<R>, L> {
@Override
public Optional<R> right() {
- return Optional.of(value);
+ return this.valueOptional == null ? this.valueOptional = Optional.of(this.value) : this.valueOptional; // Paper - reduce the optional allocation...
}
@Override