Paper/Spigot-Server-Patches/0302-Optimize-Region-File-Cache.patch

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From ef3479c926dcb3b18351f3d163558c9b1d86aa58 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Mon, 23 Jul 2018 23:40:04 -0400
Subject: [PATCH] Optimize Region File Cache
CraftBukkit added synchronization to read and write methods. This adds
much more contention on this object for accessing region files, as
the entire read and write of NBT data is now a blocking operation.
This causes issues when something then simply needs to check if a chunk exists
on the main thread, causing a block...
However, this synchronization was unnecessary, because there is already
enough synchronization done to keep things safe
1) Obtaining a Region File: Those methods are still static synchronized.
Meaning we can safely obtain a Region File concurrently.
2) RegionFile data access: Methods reading and manipulating data from
a region file are also marked synchronized, ensuring that no 2 processes
are reading or writing data at the same time.
3) Checking a region file for chunkExists: getOffset is also synchronized
ensuring that even if a chunk is currently being written, it will be safe.
By removing these synchronizations, we reduce the locking to only
when data is being write or read.
GZIP compression and NBT Buffer creation will no longer be part of the
synchronized context, reducing lock times.
Ultimately: This brings us back to Vanilla, which has had no indication of region file loss.
diff --git a/src/main/java/net/minecraft/server/RegionFileCache.java b/src/main/java/net/minecraft/server/RegionFileCache.java
Updated Upstream (Bukkit/CraftBukkit/Spigot) Upstream has released updates that appears to apply and compile correctly. This update has not been tested by PaperMC and as with ANY update, please do your own testing Warning: this commit contains more mapping changes from upstream, As always, ensure that you have working backups and test this build before deployment; Developers working on paper will, yet again, need to delete their work/Minecraft/1.13.2 folder Bukkit Changes: 7fca5fd4 SPIGOT-4558: Preserve user order in the face of copied defaults in configurations 15c9b1eb Ignore spurious slot IDs sent by client, e.g. in enchanting tables 5d2a10c5 SPIGOT-3747: Add API for force loaded chunks d6dd2bb3 SPIGOT-3538: Add getHitBlockFace for ProjectileHitEvent 771db4aa SPIGOT-794: Call EntityPlaceEvent for Minecart placement 55462509 Add InventoryView#getSlotType 2f3ce5b6 Remove EntityTransformEvent and CustomItemTagContainer from draft API f04ad7b6 Make ProjectileLaunchEvent extend EntitySpawnEvent ccb85808 Define EntitySpawnEvent b8cc3ebe Add PlayerItemDamageEvent 184a495d Ease ClassLoader Deadlocks Where Possible 11ac4728 Expand Boolean Prompt Values in Conversation API aae62d51 Added getAllSessionData() to the Conversation API. 9290ff91 Add InventoryView#getInventory API 995e530f Add API to get / set base arrow damage CraftBukkit Changes: c4a67eed SPIGOT-4556: Fix plugins closing inventory during drop events 5be2ddcb Replace version constants with methods to prevent compiler inlining a5b9c7b3 Use API method to create offset command completions 2bc7d1df SPIGOT-3747: Add API for force loaded chunks a408f375 SPIGOT-3538: Add getHitBlockFace for ProjectileHitEvent b54b9409 SPIGOT-2864: Make Arrow / Item setTicksLived behave like FallingBlock 79ded7a8 SPIGOT-1811: Death message not shown on respawn screen b4a4f15d SPIGOT-943: InventoryCloseEvent called on death regardless of open inventory 0afed592 SPIGOT-794: Call EntityPlaceEvent for Minecart placement 2b2d084a Add InventoryView#getSlotType 01a9959a Do not use deprecated ItemSpawnEvent constructor 9642498d SPIGOT-4547: Call EntitySpawnEvent as general spawn fallback event 963f4a5f Add PlayerItemDamageEvent 63db0445 Add API to get / set base arrow damage 531c25d7 Add CraftMagicNumbers.MAPPINGS_VERSION for use by NMS plugins d05c8b14 Mappings Update bd36e200 SPIGOT-4551: Ignore invalid attribute modifier slots Spigot Changes: 518206a1 Remove redundant trove depend 1959ad21 MC-11211,SPIGOT-4552: Fix placing double slabs at y = 255 29ab5e43 SPIGOT-3661: Allow arguments in restart-script 7cc46316 SPIGOT-852: Growth modifiers for beetroots, potatoes, carrots 82e117e1 Squelch "fatal: Resolve operation not in progress" message 0a1a68e7 Mappings Update & Patch Rebuild
2019-01-01 04:15:55 +01:00
index 964996976..d07222239 100644
--- a/src/main/java/net/minecraft/server/RegionFileCache.java
+++ b/src/main/java/net/minecraft/server/RegionFileCache.java
@@ -99,7 +99,7 @@ public class RegionFileCache {
@Nullable
// CraftBukkit start - call sites hoisted for synchronization
- public static synchronized NBTTagCompound read(File file, int i, int j) throws IOException {
+ public static NBTTagCompound read(File file, int i, int j) throws IOException { // Paper - remove synchronization
RegionFile regionfile = a(file, i, j);
DataInputStream datainputstream = regionfile.a(i & 31, j & 31);
@@ -112,7 +112,7 @@ public class RegionFileCache {
}
@Nullable
- public static synchronized void write(File file, int i, int j, NBTTagCompound nbttagcompound) throws IOException {
+ public static void write(File file, int i, int j, NBTTagCompound nbttagcompound) throws IOException {
int attempts = 0; Exception laste = null; while (attempts++ < 5) { try { // Paper
RegionFile regionfile = a(file, i, j);
@@ -138,7 +138,7 @@ public class RegionFileCache {
// Paper end
}
- public static synchronized boolean chunkExists(File file, int i, int j) {
+ public static boolean chunkExists(File file, int i, int j) { // Paper - remove synchronization
RegionFile regionfile = b(file, i, j);
return regionfile != null ? regionfile.d(i & 31, j & 31) : false;
--
2.21.0