Paper/patches/server/0887-Optimize-VarInts.patch
Spottedleaf 8c5b837e05 Rework async chunk api implementation
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.
2024-11-18 23:00:59 -08:00

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: astei <andrew@steinborn.me>
Date: Sat, 28 Oct 2023 19:46:21 -0400
Subject: [PATCH] Optimize VarInts
https://github.com/PaperMC/Paper/pull/6957#issuecomment-985250854
diff --git a/src/main/java/net/minecraft/network/VarInt.java b/src/main/java/net/minecraft/network/VarInt.java
index 49a8ddc269d53458cfbd639b7de838c2e5765748..74ed47659d3e615c2dae7da98d5a8cf1559625bf 100644
--- a/src/main/java/net/minecraft/network/VarInt.java
+++ b/src/main/java/net/minecraft/network/VarInt.java
@@ -9,6 +9,18 @@ public class VarInt {
private static final int DATA_BITS_PER_BYTE = 7;
public static int getByteSize(int i) {
+ // Paper start - Optimize VarInts
+ return VARINT_EXACT_BYTE_LENGTHS[Integer.numberOfLeadingZeros(i)];
+ }
+ private static final int[] VARINT_EXACT_BYTE_LENGTHS = new int[33];
+ static {
+ for (int i = 0; i <= 32; ++i) {
+ VARINT_EXACT_BYTE_LENGTHS[i] = (int) Math.ceil((31d - (i - 1)) / 7d);
+ }
+ VARINT_EXACT_BYTE_LENGTHS[32] = 1; // Special case for the number 0.
+ }
+ public static int getByteSizeOld(int i) {
+ // Paper end - Optimize VarInts
for (int j = 1; j < 5; j++) {
if ((i & -1 << j * 7) == 0) {
return j;
@@ -39,6 +51,21 @@ public class VarInt {
}
public static ByteBuf write(ByteBuf buf, int i) {
+ // Paper start - Optimize VarInts
+ // Peel the one and two byte count cases explicitly as they are the most common VarInt sizes
+ // that the proxy will write, to improve inlining.
+ if ((i & (0xFFFFFFFF << 7)) == 0) {
+ buf.writeByte(i);
+ } else if ((i & (0xFFFFFFFF << 14)) == 0) {
+ int w = (i & 0x7F | 0x80) << 8 | (i >>> 7);
+ buf.writeShort(w);
+ } else {
+ writeOld(buf, i);
+ }
+ return buf;
+ }
+ public static ByteBuf writeOld(ByteBuf buf, int i) {
+ // Paper end - Optimize VarInts
while ((i & -128) != 0) {
buf.writeByte(i & 127 | 128);
i >>>= 7;