From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Martijn Muijsers Date: Tue, 22 Aug 2023 21:38:37 +0200 Subject: [PATCH] Optimize VarInt#write and VarLong#write License: GPL-3.0 (https://www.gnu.org/licenses/gpl-3.0.html) Gale - https://galemc.org This patch is based on the following commit: "Reapply "Optimize varint writing"" By: Andrew Steinborn As part of: Velocity (https://github.com/PaperMC/Velocity) Licensed under: GPL-3.0 (https://www.gnu.org/licenses/gpl-3.0.html) * Velocity description * Inspired by the approach described at the bottom of https://richardstartin.github.io/posts/dont-use-protobuf-for-telemetry Given that we do a lot of varint writing as well, this should provide a small performance boost for larger/complex packets whilst not regressing hard on smaller packets. This includes a test to ensure that the behavior is as expected and fixes the initialization loop so that the correct results will be given. Much thanks to @octylFractal for acting as my duck while trying to figure this out. diff --git a/net/minecraft/network/VarInt.java b/net/minecraft/network/VarInt.java index 4897ff4648083ebe737ae5b32bae344af27357e4..6f8dd31582f0e1d3a71acc7a142c1f4ec0539d9e 100644 --- a/net/minecraft/network/VarInt.java +++ b/net/minecraft/network/VarInt.java @@ -51,6 +51,41 @@ public class VarInt { } public static ByteBuf write(ByteBuf buffer, int value) { + // Gale start - Velocity - optimized VarInt#write + if ((value & 0xFFFFFF80) == 0) { + buffer.writeByte(value); + } else if ((value & 0xFFFFC000) == 0) { + int w = (value & 0x7F) << 8 + | (value >>> 7) + | 0x00008000; + buffer.writeShort(w); + } else if ((value & 0xFFE00000) == 0) { + int w = (value & 0x7F) << 16 + | (value & 0x3F80) << 1 + | (value >>> 14) + | 0x00808000; + buffer.writeMedium(w); + } else if ((value & 0xF0000000) == 0) { + int w = (value & 0x7F) << 24 + | ((value & 0x3F80) << 9) + | (value & 0x1FC000) >> 6 + | (value >>> 21) + | 0x80808000; + buffer.writeInt(w); + } else { + int w = (value & 0x7F) << 24 + | (value & 0x3F80) << 9 + | (value & 0x1FC000) >> 6 + | ((value >>> 21) & 0x7F) + | 0x80808080; + buffer.writeInt(w); + buffer.writeByte(value >>> 28); + } + return buffer; + } + + static ByteBuf writeOld(ByteBuf buffer, int value) { // public -> package-private + // Gale end - Velocity - optimized VarInt#write // 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. @@ -60,11 +95,11 @@ public class VarInt { int w = (value & 0x7F | 0x80) << 8 | (value >>> 7); buffer.writeShort(w); } else { - writeOld(buffer, value); + writeOld2(buffer, value); // rename } return buffer; } - public static ByteBuf writeOld(ByteBuf buffer, int value) { + public static ByteBuf writeOld2(ByteBuf buffer, int value) { // rename // Paper end - Optimize VarInts while ((value & -128) != 0) { buffer.writeByte(value & 127 | 128); diff --git a/net/minecraft/network/VarLong.java b/net/minecraft/network/VarLong.java index ff9d84bf761797a8f695926c3cbb12c07609365d..244f8c06c6410541056a989815faf43f0fee9111 100644 --- a/net/minecraft/network/VarLong.java +++ b/net/minecraft/network/VarLong.java @@ -51,6 +51,127 @@ public class VarLong { } public static ByteBuf write(ByteBuf buffer, long value) { + // Gale start - Velocity - optimized VarLong#write + if ((value & 0xFFFFFFFFFFFFFF80L) == 0) { + buffer.writeByte((int) value); + } else if (value < 0) { + // The case of writing arbitrary longs is common + // Here, the number is negative, which has probability 1/2 for arbitrary numbers + int least7bits = (int) (value & 0xFFFFFFFL); + int w = (least7bits & 0x7F) << 24 + | (least7bits & 0x3F80) << 9 + | (least7bits & 0x1FC000) >> 6 + | ((least7bits >>> 21) & 0x7F) + | 0x80808080; + long nonLeast7Bits = value >>> 28; + int secondLeast7bits = (int) (nonLeast7Bits & 0xFFFFFFFL); + int w2 = (secondLeast7bits & 0x7F) << 24 + | ((secondLeast7bits & 0x3F80) << 9) + | (secondLeast7bits & 0x1FC000) >> 6 + | (secondLeast7bits >>> 21) + | 0x80808080; + int thirdLeast7Bits = (int) (nonLeast7Bits >>> 28); + int w3 = (thirdLeast7Bits & 0x7F) << 8 + | (thirdLeast7Bits >>> 7) + | 0x00008000; + buffer.writeInt(w); + buffer.writeInt(w2); + buffer.writeShort(w3); + } else if ((value & 0xFFFFFFFFFFFFC000L) == 0) { + int least7bits = (int) value; + int w = (least7bits & 0x7F) << 8 + | (least7bits >>> 7) + | 0x00008000; + buffer.writeShort(w); + } else if ((value & 0xFFFFFFFFFFE00000L) == 0) { + int least7bits = (int) value; + int w = (least7bits & 0x7F) << 16 + | (least7bits & 0x3F80) << 1 + | (least7bits >>> 14) + | 0x00808000; + buffer.writeMedium(w); + } else if ((value & 0xFFFFFFFFF0000000L) == 0) { + int least7bits = (int) value; + int w = (least7bits & 0x7F) << 24 + | ((least7bits & 0x3F80) << 9) + | (least7bits & 0x1FC000) >> 6 + | (least7bits >>> 21) + | 0x80808000; + buffer.writeInt(w); + } else if ((value & 0xFFFFFFF800000000L) == 0) { + int least7bits = (int) (value & 0xFFFFFFFL); + int w = (least7bits & 0x7F) << 24 + | (least7bits & 0x3F80) << 9 + | (least7bits & 0x1FC000) >> 6 + | ((least7bits >>> 21) & 0x7F) + | 0x80808080; + buffer.writeInt(w); + buffer.writeByte((int) (value >>> 28)); + } else if ((value & 0xFFFFFC0000000000L) == 0) { + int least7bits = (int) (value & 0xFFFFFFFL); + int w = (least7bits & 0x7F) << 24 + | (least7bits & 0x3F80) << 9 + | (least7bits & 0x1FC000) >> 6 + | ((least7bits >>> 21) & 0x7F) + | 0x80808080; + int secondLeast7bits = (int) (value >>> 28); + int w2 = (secondLeast7bits & 0x7F) << 8 + | (secondLeast7bits >>> 7) + | 0x00008000; + buffer.writeInt(w); + buffer.writeShort(w2); + } else if ((value & 0xFFFE000000000000L) == 0) { + int least7bits = (int) (value & 0xFFFFFFFL); + int w = (least7bits & 0x7F) << 24 + | (least7bits & 0x3F80) << 9 + | (least7bits & 0x1FC000) >> 6 + | ((least7bits >>> 21) & 0x7F) + | 0x80808080; + int secondLeast7bits = (int) (value >>> 28); + int w2 = (secondLeast7bits & 0x7F) << 16 + | (secondLeast7bits & 0x3F80) << 1 + | (secondLeast7bits >>> 14) + | 0x00808000; + buffer.writeInt(w); + buffer.writeMedium(w2); + } else if ((value & 0xFF00000000000000L) == 0) { + int least7bits = (int) (value & 0xFFFFFFFL); + int w = (least7bits & 0x7F) << 24 + | (least7bits & 0x3F80) << 9 + | (least7bits & 0x1FC000) >> 6 + | ((least7bits >>> 21) & 0x7F) + | 0x80808080; + int secondLeast7bits = (int) (value >>> 28); + int w2 = (secondLeast7bits & 0x7F) << 24 + | ((secondLeast7bits & 0x3F80) << 9) + | (secondLeast7bits & 0x1FC000) >> 6 + | (secondLeast7bits >>> 21) + | 0x80808000; + buffer.writeInt(w); + buffer.writeInt(w2); + } else { + int least7bits = (int) (value & 0xFFFFFFFL); + int w = (least7bits & 0x7F) << 24 + | (least7bits & 0x3F80) << 9 + | (least7bits & 0x1FC000) >> 6 + | ((least7bits >>> 21) & 0x7F) + | 0x80808080; + long nonLeast7Bits = value >>> 28; + int secondLeast7bits = (int) (nonLeast7Bits & 0xFFFFFFFL); + int w2 = (secondLeast7bits & 0x7F) << 24 + | ((secondLeast7bits & 0x3F80) << 9) + | (secondLeast7bits & 0x1FC000) >> 6 + | (secondLeast7bits >>> 21) + | 0x80808080; + buffer.writeInt(w); + buffer.writeInt(w2); + buffer.writeByte((int) (nonLeast7Bits >>> 28)); + } + return buffer; + } + + static ByteBuf writeOld(ByteBuf buffer, long value) { // public -> package-private + // Gale end - Velocity - optimized VarLong#write while ((value & -128L) != 0L) { buffer.writeByte((int)(value & 127L) | 128); value >>>= 7;