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Fix patch "Faster redstone torch rapid clock removal" (#2014)

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Tux pointed out the patch still has O(n^2) time complexity since
the sublist class in arraylist does not override clear() from
AbstractList, which uses a forward moving iterator to clear
the list.

Resolved by using a peek and poll from ArrayDeque.

This patch also removes the useless WeakHashMap which holds
the list (it mapped world->list) and replaces it with a
field on World.
This commit is contained in:
Spottedleaf
2019-05-10 08:48:58 -07:00
parent 69ca68db14
commit 396186a950
13 changed files with 84 additions and 34 deletions
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70
Spigot-Server-Patches/Faster-redstone-torch-rapid-clock-removal.patch
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@@ -6,29 +6,67 @@ Subject: [PATCH] Faster redstone torch rapid clock removal
Only resize the the redstone torch list once, since resizing arrays / lists is costly
diff --git a/src/main/java/net/minecraft/server/BlockRedstoneTorch.java b/src/main/java/net/minecraft/server/BlockRedstoneTorch.java
index a99f979ef..a79484e3e 100644
index a99f979ef..919ba8a14 100644
--- a/src/main/java/net/minecraft/server/BlockRedstoneTorch.java
+++ b/src/main/java/net/minecraft/server/BlockRedstoneTorch.java
@@ -0,0 +0,0 @@ import org.bukkit.event.block.BlockRedstoneEvent; // CraftBukkit
public class BlockRedstoneTorch extends BlockTorch {
public static final BlockStateBoolean LIT = BlockProperties.r;
- private static final Map<IBlockAccess, List<BlockRedstoneTorch.RedstoneUpdateInfo>> b = new WeakHashMap();
+ // Paper - Move the mapped list to World
protected BlockRedstoneTorch(Block.Info block_info) {
super(block_info);
@@ -0,0 +0,0 @@ public class BlockRedstoneTorch extends BlockTorch {
}
public static void a(IBlockData iblockdata, World world, BlockPosition blockposition, Random random, boolean flag) {
List list = (List) BlockRedstoneTorch.b.get(world);
- List list = (List) BlockRedstoneTorch.b.get(world);
+ // Paper start
+ java.util.ArrayDeque<BlockRedstoneTorch.RedstoneUpdateInfo> redstoneUpdateInfos = world.redstoneUpdateInfos;
- while (list != null && !list.isEmpty() && world.getTime() - ((BlockRedstoneTorch.RedstoneUpdateInfo) list.get(0)).b > 60L) {
- list.remove(0);
+ // Paper start
+ if (list != null) {
+ int index = 0;
+ while (index < list.size() && world.getTime() - ((BlockRedstoneTorch.RedstoneUpdateInfo) list.get(index)).getTime() > 60L) {
+ index++;
+ }
+ if (index > 0) {
+ list.subList(0, index).clear();
+ if (redstoneUpdateInfos != null) {
+ BlockRedstoneTorch.RedstoneUpdateInfo curr;
+ while ((curr = redstoneUpdateInfos.peek()) != null && world.getTime() - curr.getTime() > 60L) {
+ redstoneUpdateInfos.poll();
+ }
}
+ // Paper end
// CraftBukkit start
org.bukkit.plugin.PluginManager manager = world.getServer().getPluginManager();
@@ -0,0 +0,0 @@ public class BlockRedstoneTorch extends BlockTorch {
}
private static boolean a(World world, BlockPosition blockposition, boolean flag) {
- List<BlockRedstoneTorch.RedstoneUpdateInfo> list = (List) BlockRedstoneTorch.b.computeIfAbsent(world, (iblockaccess) -> {
- return Lists.newArrayList();
- });
+ // Paper start
+ java.util.ArrayDeque<BlockRedstoneTorch.RedstoneUpdateInfo> list = world.redstoneUpdateInfos;
+ if (list == null) {
+ list = world.redstoneUpdateInfos = new java.util.ArrayDeque<>();
+ }
+
if (flag) {
list.add(new BlockRedstoneTorch.RedstoneUpdateInfo(blockposition.immutableCopy(), world.getTime()));
@@ -0,0 +0,0 @@ public class BlockRedstoneTorch extends BlockTorch {
int i = 0;
- for (int j = 0; j < list.size(); ++j) {
- BlockRedstoneTorch.RedstoneUpdateInfo blockredstonetorch_redstoneupdateinfo = (BlockRedstoneTorch.RedstoneUpdateInfo) list.get(j);
-
+ for (java.util.Iterator<BlockRedstoneTorch.RedstoneUpdateInfo> iterator = list.iterator(); iterator.hasNext();) {
+ BlockRedstoneTorch.RedstoneUpdateInfo blockredstonetorch_redstoneupdateinfo = iterator.next();
+ // Paper end
if (blockredstonetorch_redstoneupdateinfo.a.equals(blockposition)) {
++i;
if (i >= 8) {
@@ -0,0 +0,0 @@ public class BlockRedstoneTorch extends BlockTorch {
public static class RedstoneUpdateInfo {
@@ -38,4 +76,16 @@ index a99f979ef..a79484e3e 100644
public RedstoneUpdateInfo(BlockPosition blockposition, long i) {
this.a = blockposition;
diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
index de09ed97e..3305e110c 100644
--- a/src/main/java/net/minecraft/server/World.java
+++ b/src/main/java/net/minecraft/server/World.java
@@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose
private org.spigotmc.TickLimiter tileLimiter;
private int tileTickPosition;
public final Map<Explosion.CacheKey, Float> explosionDensityCache = new HashMap<>(); // Paper - Optimize explosions
+ public java.util.ArrayDeque<BlockRedstoneTorch.RedstoneUpdateInfo> redstoneUpdateInfos; // Paper - Move from Map in BlockRedstoneTorch to here
public CraftWorld getWorld() {
return this.world;
--