Paper/patches/server/0816-Execute-chunk-tasks-fairly-for-worlds-while-waiting-.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: Tue, 28 Dec 2021 07:19:01 -0800
Subject: [PATCH] Execute chunk tasks fairly for worlds while waiting for next
tick
Currently, only the first world would have had tasks executed.
This might result in chunks loading far slower in the nether,
for example.
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index efe7a3afaf5ef548bded4dc2957375fdbc605d63..8a51a5da86e3e9b277109b0acf2982197292682e 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -1308,6 +1308,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
this.executeMidTickTasks(); // Paper - execute chunk tasks mid tick
return true;
} else {
+ boolean ret = false; // Paper - force execution of all worlds, do not just bias the first
if (this.haveTime()) {
Iterator iterator = this.getAllLevels().iterator();
@@ -1315,12 +1316,12 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
ServerLevel worldserver = (ServerLevel) iterator.next();
if (worldserver.getChunkSource().pollTask()) {
- return true;
+ ret = true; // Paper - force execution of all worlds, do not just bias the first
}
}
}
- return false;
+ return ret; // Paper - force execution of all worlds, do not just bias the first
}
}