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01a13871de
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.
55 lines
2.4 KiB
Diff
55 lines
2.4 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Wyatt Childers <wchilders@nearce.com>
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Date: Sat, 4 Jul 2020 23:07:43 -0400
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Subject: [PATCH] Optimize the advancement data player iteration to be O(N)
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rather than O(N^2)
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diff --git a/src/main/java/net/minecraft/server/PlayerAdvancements.java b/src/main/java/net/minecraft/server/PlayerAdvancements.java
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index 3f7f6a43ac0bf2efb0e66dc96438febbd92113e9..0c2f12e7930646a3da53a50f38be62e0cb1ed2b7 100644
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--- a/src/main/java/net/minecraft/server/PlayerAdvancements.java
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+++ b/src/main/java/net/minecraft/server/PlayerAdvancements.java
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@@ -435,6 +435,16 @@ public class PlayerAdvancements {
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}
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private void ensureVisibility(Advancement advancement) {
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+ // Paper start
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+ ensureVisibility(advancement, IterationEntryPoint.ROOT);
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+ }
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+ private enum IterationEntryPoint {
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+ ROOT,
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+ ITERATOR,
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+ PARENT_OF_ITERATOR
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+ }
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+ private void ensureVisibility(Advancement advancement, IterationEntryPoint entryPoint) {
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+ // Paper end
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boolean flag = this.shouldBeVisible(advancement);
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boolean flag1 = this.visible.contains(advancement);
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@@ -450,15 +460,23 @@ public class PlayerAdvancements {
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}
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if (flag != flag1 && advancement.getParent() != null) {
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- this.ensureVisibility(advancement.getParent());
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+ // Paper start - If we're not coming from an iterator consider this to be a root entry, otherwise
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+ // market that we're entering from the parent of an iterator.
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+ this.ensureVisibility(advancement.getParent(), entryPoint == IterationEntryPoint.ITERATOR ? IterationEntryPoint.PARENT_OF_ITERATOR : IterationEntryPoint.ROOT);
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}
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+ // If this is true, we've went through a child iteration, entered the parent, processed the parent
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+ // and are about to reprocess the children. Stop processing here to prevent O(N^2) processing.
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+ if (entryPoint == IterationEntryPoint.PARENT_OF_ITERATOR) {
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+ return;
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+ } // Paper end
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+
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Iterator iterator = advancement.getChildren().iterator();
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while (iterator.hasNext()) {
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Advancement advancement1 = (Advancement) iterator.next();
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- this.ensureVisibility(advancement1);
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+ this.ensureVisibility(advancement1, IterationEntryPoint.ITERATOR); // Paper - Mark this call as being from iteration
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}
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}
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