Paper/Spigot-Server-Patches/0437-Optimise-random-block-ticking.patch

From a9e20c5c7a618f765b43d7ce1358544b702855f5 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Mon, 27 Jan 2020 21:28:00 -0800
Subject: [PATCH] Optimise random block ticking

Massive performance improvement for random block ticking.
The performance increase comes from the fact that the vast
majority of attempted block ticks (~95% in my testing) fail
because the randomly selected block is not tickable.

Now only tickable blocks are targeted, however this means that
the maximum number of block ticks occurs per chunk. However,
not all chunks are going to be targeted. The percent chance
of a chunk being targeted is based on how many tickable blocks
are in the chunk.
This means that while block ticks are spread out less, the
total number of blocks ticked per world tick remains the same.
Therefore, the chance of a random tickable block being ticked
remains the same.

diff --git a/src/main/java/com/destroystokyo/paper/util/math/ThreadUnsafeRandom.java b/src/main/java/com/destroystokyo/paper/util/math/ThreadUnsafeRandom.java
new file mode 100644
index 0000000000..3edc8e52e0
--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/util/math/ThreadUnsafeRandom.java
@@ -0,0 +1,46 @@
+package com.destroystokyo.paper.util.math;
+
+import java.util.Random;
+
+public final class ThreadUnsafeRandom extends Random {
+
+    // See javadoc and internal comments for java.util.Random where these values come from, how they are used, and the author for them.
+    private static final long multiplier = 0x5DEECE66DL;
+    private static final long addend = 0xBL;
+    private static final long mask = (1L << 48) - 1;
+
+    private static long initialScramble(long seed) {
+        return (seed ^ multiplier) & mask;
+    }
+
+    private long seed;
+
+    @Override
+    public void setSeed(long seed) {
+        // note: called by Random constructor
+        this.seed = initialScramble(seed);
+    }
+
+    @Override
+    protected int next(int bits) {
+        // avoid the expensive CAS logic used by superclass
+        return (int) (((this.seed = this.seed * multiplier + addend) & mask) >>> (48 - bits));
+    }
+
+    // Taken from
+    // https://lemire.me/blog/2016/06/27/a-fast-alternative-to-the-modulo-reduction/
+    // https://github.com/lemire/Code-used-on-Daniel-Lemire-s-blog/blob/master/2016/06/25/fastrange.c
+    // Original license is public domain
+    public static int fastRandomBounded(final long randomInteger, final long limit) {
+        // randomInteger must be [0, pow(2, 32))
+        // limit must be [0, pow(2, 32))
+        return (int)((randomInteger * limit) >>> 32);
+    }
+
+    @Override
+    public int nextInt(int bound) {
+        // yes this breaks random's spec
+        // however there's nothing that uses this class that relies on it
+        return fastRandomBounded(this.next(32) & 0xFFFFFFFFL, bound);
+    }
+}
diff --git a/src/main/java/net/minecraft/server/Block.java b/src/main/java/net/minecraft/server/Block.java
index e29ec958b3..e40375b67a 100644
--- a/src/main/java/net/minecraft/server/Block.java
+++ b/src/main/java/net/minecraft/server/Block.java
@@ -109,8 +109,8 @@ public class Block implements IMaterial {
         return iblockdata.d(iblockaccess, blockposition, EnumDirection.UP) && this.n < 14;
     }
 
-    @Deprecated
-    public boolean d(IBlockData iblockdata) {
+    public final boolean isAir(IBlockData iblockdata) { return this.d(iblockdata); } // Paper - OBFHELPER
+    @Deprecated public boolean d(IBlockData iblockdata) { // Paper - OBFHELPER
         return false;
     }
 
diff --git a/src/main/java/net/minecraft/server/BlockFluids.java b/src/main/java/net/minecraft/server/BlockFluids.java
index 6d351f0979..a44f65f40d 100644
--- a/src/main/java/net/minecraft/server/BlockFluids.java
+++ b/src/main/java/net/minecraft/server/BlockFluids.java
@@ -27,7 +27,7 @@ public class BlockFluids extends Block implements IFluidSource {
 
     @Override
     public void b(IBlockData iblockdata, WorldServer worldserver, BlockPosition blockposition, Random random) {
-        worldserver.getFluid(blockposition).b(worldserver, blockposition, random);
+        iblockdata.getFluid().b(worldserver, blockposition, random); // Paper - avoid getType call
     }
 
     @Override
diff --git a/src/main/java/net/minecraft/server/BlockPosition.java b/src/main/java/net/minecraft/server/BlockPosition.java
index e76528f199..e650a2e48d 100644
--- a/src/main/java/net/minecraft/server/BlockPosition.java
+++ b/src/main/java/net/minecraft/server/BlockPosition.java
@@ -450,6 +450,7 @@ public class BlockPosition extends BaseBlockPosition implements MinecraftSeriali
             return this.d(MathHelper.floor(d0), MathHelper.floor(d1), MathHelper.floor(d2));
         }
 
+        public final BlockPosition.MutableBlockPosition setValues(final BaseBlockPosition baseblockposition) { return this.g(baseblockposition); } // Paper - OBFHELPER
         public BlockPosition.MutableBlockPosition g(BaseBlockPosition baseblockposition) {
             return this.d(baseblockposition.getX(), baseblockposition.getY(), baseblockposition.getZ());
         }
diff --git a/src/main/java/net/minecraft/server/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
index 38ab4197b2..971c0315d5 100644
--- a/src/main/java/net/minecraft/server/Chunk.java
+++ b/src/main/java/net/minecraft/server/Chunk.java
@@ -52,6 +52,8 @@ public class Chunk implements IChunkAccess {
     private final ChunkCoordIntPair loc; public final long coordinateKey; // Paper - cache coordinate key
     private volatile boolean x;
 
+    final com.destroystokyo.paper.util.maplist.IBlockDataList tickingList = new com.destroystokyo.paper.util.maplist.IBlockDataList(); // Paper
+
     public Chunk(World world, ChunkCoordIntPair chunkcoordintpair, BiomeStorage biomestorage) {
         this(world, chunkcoordintpair, biomestorage, ChunkConverter.a, TickListEmpty.b(), TickListEmpty.b(), 0L, (ChunkSection[]) null, (Consumer) null);
     }
@@ -124,6 +126,18 @@ public class Chunk implements IChunkAccess {
         this.v = consumer;
         if (achunksection != null) {
             if (this.sections.length == achunksection.length) {
+                // Paper start - maintain a list of ticking blocks in a chunk
+                for (ChunkSection section : achunksection) {
+                    if (section != null) {
+                        section.chunk = this;
+                        int offset = com.destroystokyo.paper.util.maplist.IBlockDataList.getLocationKey(0, section.yPos, 0);
+                        for (it.unimi.dsi.fastutil.longs.LongIterator iterator = section.tickingList.getRawIterator(); iterator.hasNext();) {
+                            long raw = iterator.nextLong();
+                            this.tickingList.add(com.destroystokyo.paper.util.maplist.IBlockDataList.getLocationFromRaw(raw) + offset, com.destroystokyo.paper.util.maplist.IBlockDataList.getBlockDataFromRaw(raw));
+                        }
+                    }
+                }
+                // Paper end
                 System.arraycopy(achunksection, 0, this.sections, 0, this.sections.length);
             } else {
                 Chunk.LOGGER.warn("Could not set level chunk sections, array length is {} instead of {}", achunksection.length, this.sections.length);
@@ -490,8 +504,8 @@ public class Chunk implements IChunkAccess {
         this.entities.remove(entity); // Paper
     }
 
-    @Override
-    public int a(HeightMap.Type heightmap_type, int i, int j) {
+    public int getHighestBlockY(HeightMap.Type heightmap_type, int i, int j) { return this.a(heightmap_type, i, j) + 1; } // Paper - sort of an obfhelper, but without -1
+    @Override public int a(HeightMap.Type heightmap_type, int i, int j) { // Paper
         return ((HeightMap) this.heightMap.get(heightmap_type)).a(i & 15, j & 15) - 1;
     }
 
diff --git a/src/main/java/net/minecraft/server/ChunkSection.java b/src/main/java/net/minecraft/server/ChunkSection.java
index 4526527aca..8b28fb5ee1 100644
--- a/src/main/java/net/minecraft/server/ChunkSection.java
+++ b/src/main/java/net/minecraft/server/ChunkSection.java
@@ -5,12 +5,15 @@ import javax.annotation.Nullable;
 public class ChunkSection {
 
     public static final DataPalette<IBlockData> GLOBAL_PALETTE = new DataPaletteGlobal<>(Block.REGISTRY_ID, Blocks.AIR.getBlockData());
-    private final int yPos;
+    final int yPos; // Paper - private -> package-private
     short nonEmptyBlockCount; // Paper - private -> package-private
-    private short tickingBlockCount;
+    short tickingBlockCount; // Paper - private -> package-private
     private short e;
     final DataPaletteBlock<IBlockData> blockIds;
 
+    Chunk chunk; // Paper
+    final com.destroystokyo.paper.util.maplist.IBlockDataList tickingList = new com.destroystokyo.paper.util.maplist.IBlockDataList(); // Paper
+
     public ChunkSection(int i) {
         // Paper start - add parameters
         this(i, (IChunkAccess)null, (IWorldReader)null, true);
@@ -31,6 +34,11 @@ public class ChunkSection {
         this.tickingBlockCount = short1;
         this.e = short2;
         this.blockIds = new DataPaletteBlock<>(ChunkSection.GLOBAL_PALETTE, Block.REGISTRY_ID, GameProfileSerializer::d, GameProfileSerializer::a, Blocks.AIR.getBlockData(), world instanceof GeneratorAccess ? ((GeneratorAccess) world).getMinecraftWorld().chunkPacketBlockController.getPredefinedBlockData(world, chunk, this, initializeBlocks) : null, initializeBlocks); // Paper - Anti-Xray - Add predefined block data
+        // Paper start
+        if (chunk instanceof Chunk) {
+            this.chunk = (Chunk)chunk;
+        }
+        // Paper end
     }
 
     public IBlockData getType(int i, int j, int k) {
@@ -69,6 +77,12 @@ public class ChunkSection {
             --this.nonEmptyBlockCount;
             if (iblockdata1.q()) {
                 --this.tickingBlockCount;
+                // Paper start
+                this.tickingList.remove(i, j, k);
+                if (this.chunk != null) {
+                    this.chunk.tickingList.remove(i, j + this.yPos, k);
+                }
+                // Paper end
             }
         }
 
@@ -80,6 +94,12 @@ public class ChunkSection {
             ++this.nonEmptyBlockCount;
             if (iblockdata.q()) {
                 ++this.tickingBlockCount;
+                // Paper start
+                this.tickingList.add(i, j, k, iblockdata);
+                if (this.chunk != null) {
+                    this.chunk.tickingList.add(i, j + this.yPos, k, iblockdata);
+                }
+                // Paper end
             }
         }
 
@@ -115,23 +135,39 @@ public class ChunkSection {
     }
 
     public void recalcBlockCounts() {
+        // Paper start
+        int offset = com.destroystokyo.paper.util.maplist.IBlockDataList.getLocationKey(0, this.yPos, 0);
+        if (this.chunk != null) {
+            for (it.unimi.dsi.fastutil.longs.LongIterator iterator = this.tickingList.getRawIterator(); iterator.hasNext();) {
+                long raw = iterator.nextLong();
+                this.chunk.tickingList.remove(com.destroystokyo.paper.util.maplist.IBlockDataList.getLocationFromRaw(raw) + offset);
+            }
+        }
+        this.tickingList.clear();
+        // Paper end
         this.nonEmptyBlockCount = 0;
         this.tickingBlockCount = 0;
         this.e = 0;
-        this.blockIds.a((iblockdata, i) -> {
+        this.blockIds.forEachLocation((iblockdata, location) -> { // Paper
             Fluid fluid = iblockdata.getFluid();
 
             if (!iblockdata.isAir()) {
-                this.nonEmptyBlockCount = (short) (this.nonEmptyBlockCount + i);
+                this.nonEmptyBlockCount = (short) (this.nonEmptyBlockCount + 1); // Paper
                 if (iblockdata.q()) {
-                    this.tickingBlockCount = (short) (this.tickingBlockCount + i);
+                    this.tickingBlockCount = (short) (this.tickingBlockCount + 1); // Paper
+                    // Paper start
+                    this.tickingList.add(location, iblockdata);
+                    if (this.chunk != null) {
+                        this.chunk.tickingList.add(location + offset, iblockdata);
+                    }
+                    // Paper end
                 }
             }
 
             if (!fluid.isEmpty()) {
-                this.nonEmptyBlockCount = (short) (this.nonEmptyBlockCount + i);
+                this.nonEmptyBlockCount = (short) (this.nonEmptyBlockCount + 1); // Paper
                 if (fluid.h()) {
-                    this.e = (short) (this.e + i);
+                    this.e = (short) (this.e + 1); // Paper
                 }
             }
 
diff --git a/src/main/java/net/minecraft/server/DataBits.java b/src/main/java/net/minecraft/server/DataBits.java
index f9680b6830..a61cffa3f4 100644
--- a/src/main/java/net/minecraft/server/DataBits.java
+++ b/src/main/java/net/minecraft/server/DataBits.java
@@ -127,4 +127,46 @@ public class DataBits {
 
         }
     }
+
+    // Paper start
+    public final void forEach(DataBitConsumer consumer) {
+        // Note: copied from above
+        int i = this.a.length;
+
+        if (i != 0) {
+            int j = 0;
+            long k = this.a[0];
+            long l = i > 1 ? this.a[1] : 0L;
+
+            for (int i1 = 0; i1 < this.d; ++i1) {
+                int j1 = i1 * this.b;
+                int k1 = j1 >> 6;
+                int l1 = (i1 + 1) * this.b - 1 >> 6;
+                int i2 = j1 ^ k1 << 6;
+
+                if (k1 != j) {
+                    k = l;
+                    l = k1 + 1 < i ? this.a[k1 + 1] : 0L;
+                    j = k1;
+                }
+
+                if (k1 == l1) {
+                    consumer.accept(i1, (int) (k >>> i2 & this.c));
+                } else {
+                    int j2 = 64 - i2;
+
+                    consumer.accept(i1, (int) ((k >>> i2 | l << j2) & this.c));
+                }
+            }
+
+        }
+    }
+
+    @FunctionalInterface
+    static interface DataBitConsumer {
+
+        void accept(int location, int data);
+
+    }
+    // Paper end
 }
diff --git a/src/main/java/net/minecraft/server/DataPaletteBlock.java b/src/main/java/net/minecraft/server/DataPaletteBlock.java
index 44aed67274..fa664897fb 100644
--- a/src/main/java/net/minecraft/server/DataPaletteBlock.java
+++ b/src/main/java/net/minecraft/server/DataPaletteBlock.java
@@ -287,6 +287,14 @@ public class DataPaletteBlock<T> implements DataPaletteExpandable<T> {
         });
     }
 
+    // Paper start
+    public void forEachLocation(DataPaletteBlock.a<T> datapaletteblock_a) {
+        this.getDataBits().forEach((int location, int data) -> {
+            datapaletteblock_a.accept(this.getDataPalette().getObject(data), location);
+        });
+    }
+    // Paper end
+
     @FunctionalInterface
     public interface a<T> {
 
diff --git a/src/main/java/net/minecraft/server/EntityTurtle.java b/src/main/java/net/minecraft/server/EntityTurtle.java
index dd02cb3485..b24a5100b4 100644
--- a/src/main/java/net/minecraft/server/EntityTurtle.java
+++ b/src/main/java/net/minecraft/server/EntityTurtle.java
@@ -29,7 +29,7 @@ public class EntityTurtle extends EntityAnimal {
 
     public final void setHome(BlockPosition pos) { g(pos); } // Paper - OBFHELPER
     public void g(BlockPosition blockposition) {
-        this.datawatcher.set(EntityTurtle.bx, blockposition);
+        this.datawatcher.set(EntityTurtle.bx, blockposition.immutableCopy()); // Paper - make sure home position can't change
     }
 
     public final BlockPosition getHome() { return this.es(); } // Paper - OBFHELPER
diff --git a/src/main/java/net/minecraft/server/IBlockData.java b/src/main/java/net/minecraft/server/IBlockData.java
index de43881653..e821c236b4 100644
--- a/src/main/java/net/minecraft/server/IBlockData.java
+++ b/src/main/java/net/minecraft/server/IBlockData.java
@@ -22,11 +22,15 @@ public class IBlockData extends BlockDataAbstract<Block, IBlockData> implements
     private IBlockData.a c;
     private final int d;
     private final boolean e;
+    private final boolean isAir; // Paper
+    private final boolean isTicking; // Paper
 
     public IBlockData(Block block, ImmutableMap<IBlockState<?>, Comparable<?>> immutablemap) {
         super(block, immutablemap);
         this.d = block.a(this);
         this.e = block.o(this);
+        this.isAir = this.getBlock().isAir(this); // Paper
+        this.isTicking = this.getBlock().isTicking(this); // Paper
     }
 
     public void c() {
@@ -81,8 +85,8 @@ public class IBlockData extends BlockDataAbstract<Block, IBlockData> implements
         return this.d;
     }
 
-    public boolean isAir() {
-        return this.getBlock().d(this);
+    public final boolean isAir() { // Paper - compile fail if the impl changes
+        return this.isAir; // Paper - improve inlining of isAir
     }
 
     public MaterialMapColor c(IBlockAccess iblockaccess, BlockPosition blockposition) {
@@ -267,12 +271,19 @@ public class IBlockData extends BlockDataAbstract<Block, IBlockData> implements
         return this.getBlock().a(tag);
     }
 
+    private Fluid fluidData; // Paper - cache result
     public Fluid getFluid() {
-        return this.getBlock().a_(this);
+        // Paper start
+        // This can't be done during the constructor, order issues
+        if (this.fluidData != null) {
+            return this.fluidData;
+        }
+        return this.fluidData = this.getBlock().a_(this);
+        // Paper end
     }
 
     public boolean q() {
-        return this.getBlock().isTicking(this);
+        return this.isTicking; // Paper
     }
 
     public final SoundEffectType getStepSound() { return this.r(); } // Paper - OBFHELPER
diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
index 28b6c9a083..d554d4cf0f 100644
--- a/src/main/java/net/minecraft/server/World.java
+++ b/src/main/java/net/minecraft/server/World.java
@@ -1557,10 +1557,19 @@ public abstract class World implements GeneratorAccess, AutoCloseable {
     public abstract TagRegistry t();
 
     public BlockPosition a(int i, int j, int k, int l) {
+        // Paper start - allow use of mutable pos
+        BlockPosition.MutableBlockPosition ret = new BlockPosition.MutableBlockPosition();
+        this.getRandomBlockPosition(i, j, k, l, ret);
+        return ret.immutableCopy();
+    }
+
+    public final BlockPosition.MutableBlockPosition getRandomBlockPosition(int i, int j, int k, int l, BlockPosition.MutableBlockPosition out) {
+        // Paper end
         this.i = this.i * 3 + 1013904223;
         int i1 = this.i >> 2;
 
-        return new BlockPosition(i + (i1 & 15), j + (i1 >> 16 & l), k + (i1 >> 8 & 15));
+        out.setValues(i + (i1 & 15), j + (i1 >> 16 & l), k + (i1 >> 8 & 15)); // Paper - change to setValues call
+        return out; // Paper
     }
 
     public boolean isSavingDisabled() {
diff --git a/src/main/java/net/minecraft/server/WorldServer.java b/src/main/java/net/minecraft/server/WorldServer.java
index 9211f996c0..eb99819e51 100644
--- a/src/main/java/net/minecraft/server/WorldServer.java
+++ b/src/main/java/net/minecraft/server/WorldServer.java
@@ -531,6 +531,11 @@ public class WorldServer extends World {
         });
     }
 
+    // Paper start - optimise random block ticking
+    private final BlockPosition.MutableBlockPosition chunkTickMutablePosition = new BlockPosition.MutableBlockPosition();
+    private final com.destroystokyo.paper.util.math.ThreadUnsafeRandom randomTickRandom = new com.destroystokyo.paper.util.math.ThreadUnsafeRandom();
+    // Paper end
+
     public void a(Chunk chunk, int i) {
         ChunkCoordIntPair chunkcoordintpair = chunk.getPos();
         boolean flag = this.isRaining();
@@ -539,10 +544,10 @@ public class WorldServer extends World {
         GameProfilerFiller gameprofilerfiller = this.getMethodProfiler();
 
         gameprofilerfiller.enter("thunder");
-        BlockPosition blockposition;
+        final BlockPosition.MutableBlockPosition blockposition = this.chunkTickMutablePosition; // Paper - use mutable to reduce allocation rate, final to force compile fail on change
 
-        if (!this.paperConfig.disableThunder && flag && this.U() && this.random.nextInt(100000) == 0) { // Paper - Disable thunder
-            blockposition = this.a(this.a(j, 0, k, 15));
+        if (!this.paperConfig.disableThunder && flag && this.U() && this.randomTickRandom.nextInt(100000) == 0) { // Paper - Disable thunder // Paper - optimise random ticking
+            blockposition.setValues(this.a(this.getRandomBlockPosition(j, 0, k, 15, blockposition))); // Paper
             if (this.isRainingAt(blockposition)) {
                 DifficultyDamageScaler difficultydamagescaler = this.getDamageScaler(blockposition);
                 boolean flag1 = this.getGameRules().getBoolean(GameRules.DO_MOB_SPAWNING) && this.random.nextDouble() < (double) difficultydamagescaler.b() * paperConfig.skeleHorseSpawnChance; // Paper
@@ -561,61 +566,81 @@ public class WorldServer extends World {
         }
 
         gameprofilerfiller.exitEnter("iceandsnow");
-        if (!this.paperConfig.disableIceAndSnow && this.random.nextInt(16) == 0) { // Paper - Disable ice and snow
-            blockposition = this.getHighestBlockYAt(HeightMap.Type.MOTION_BLOCKING, this.a(j, 0, k, 15));
-            BlockPosition blockposition1 = blockposition.down();
+        if (!this.paperConfig.disableIceAndSnow && this.randomTickRandom.nextInt(16) == 0) { // Paper - Disable ice and snow // Paper - optimise random ticking
+            // Paper start - optimise chunk ticking
+            this.getRandomBlockPosition(j, 0, k, 15, blockposition);
+            int normalY = chunk.getHighestBlockY(HeightMap.Type.MOTION_BLOCKING, blockposition.getX() & 15, blockposition.getZ() & 15);
+            int downY = normalY - 1;
+            blockposition.setY(normalY);
+            // Paper end
             BiomeBase biomebase = this.getBiome(blockposition);
 
-            if (biomebase.a((IWorldReader) this, blockposition1)) {
-                org.bukkit.craftbukkit.event.CraftEventFactory.handleBlockFormEvent(this, blockposition1, Blocks.ICE.getBlockData(), null); // CraftBukkit
+            // Paper start - optimise chunk ticking
+            blockposition.setY(downY);
+            if (biomebase.a((IWorldReader) this, blockposition)) {
+                org.bukkit.craftbukkit.event.CraftEventFactory.handleBlockFormEvent(this, blockposition, Blocks.ICE.getBlockData(), null); // CraftBukkit
+                // Paper end
             }
 
+            blockposition.setY(normalY); // Paper
             if (flag && biomebase.b(this, blockposition)) {
                 org.bukkit.craftbukkit.event.CraftEventFactory.handleBlockFormEvent(this, blockposition, Blocks.SNOW.getBlockData(), null); // CraftBukkit
             }
 
-            if (flag && this.getBiome(blockposition1).d() == BiomeBase.Precipitation.RAIN) {
-                this.getType(blockposition1).getBlock().c((World) this, blockposition1);
+            // Paper start - optimise chunk ticking
+            blockposition.setY(downY);
+            if (flag && this.getBiome(blockposition).d() == BiomeBase.Precipitation.RAIN) {
+                chunk.getType(blockposition).getBlock().c((World) this, blockposition);
+                // Paper end
             }
         }
 
-        gameprofilerfiller.exitEnter("tickBlocks");
-        timings.chunkTicksBlocks.startTiming(); // Paper
-        if (i > 0) {
-            ChunkSection[] achunksection = chunk.getSections();
-            int l = achunksection.length;
-
-            for (int i1 = 0; i1 < l; ++i1) {
-                ChunkSection chunksection = achunksection[i1];
-
-                if (chunksection != Chunk.a && chunksection.d()) {
-                    int j1 = chunksection.getYPosition();
+        // Paper start - optimise random block ticking
+        gameprofilerfiller.exit();
+        int blocks = chunk.tickingList.size();
+        if (i > 0 && blocks > 0) {
+            if ((this.randomTickRandom.nextInt() & (16 * 16 * 256 - 1)) > blocks) {
+                // we optimise random block ticking by realising that most of the blocks we will try to tick
+                // are not tickable. Instead we only tick tickable blocks, but only if the above
+                // statement is true
+                // Note: The number of blocks that get ticked per tick still REMAIN the same.
+                return;
+            }
+            gameprofilerfiller.enter("tickBlocks");
+            timings.chunkTicksBlocks.startTiming(); // Paper
 
-                    for (int k1 = 0; k1 < i; ++k1) {
-                        BlockPosition blockposition2 = this.a(j, j1, k, 15);
+            int toTick = i << 4; // i * 16
 
-                        gameprofilerfiller.enter("randomTick");
-                        IBlockData iblockdata = chunksection.getType(blockposition2.getX() - j, blockposition2.getY() - j1, blockposition2.getZ() - k);
+            gameprofilerfiller.enter("randomTick");
+            for (int tick = 0; tick < toTick; ++tick) {
+                int tickingSize = chunk.tickingList.size();
+                if (tickingSize == 0) {
+                    break;
+                }
 
-                        if (iblockdata.q()) {
-                            iblockdata.getBlock().randomTick = true; // Paper - fix MC-113809
-                            iblockdata.b(this, blockposition2, this.random);
-                            iblockdata.getBlock().randomTick = false; // Paper - fix MC-113809
-                        }
+                int index = this.randomTickRandom.nextInt(tickingSize);
+                long raw = chunk.tickingList.getRaw(index);
+                int location = com.destroystokyo.paper.util.maplist.IBlockDataList.getLocationFromRaw(raw);
+                int randomX = location & 15;
+                int randomY = (location >>> (4 + 4)) & 255;
+                int randomZ = (location >>> 4) & 15;
 
-                        Fluid fluid = iblockdata.getFluid();
+                BlockPosition blockposition2 = blockposition.setValues(j + randomX, randomY, k + randomZ);
+                IBlockData iblockdata = com.destroystokyo.paper.util.maplist.IBlockDataList.getBlockDataFromRaw(raw);
 
-                        if (fluid.h()) {
-                            fluid.b(this, blockposition2, this.random);
-                        }
+                iblockdata.getBlock().randomTick = true; // Paper - fix MC-113809
+                iblockdata.b(this, blockposition2, this.randomTickRandom);
+                iblockdata.getBlock().randomTick = false; // Paper - fix MC-113809
 
-                        gameprofilerfiller.exit();
-                    }
-                }
+                // We drop the fluid tick since LAVA is ALREADY TICKED by the above method.
+                // TODO CHECK ON UPDATE
             }
+
+            gameprofilerfiller.exit();
+            timings.chunkTicksBlocks.stopTiming(); // Paper
+            gameprofilerfiller.exit();
+            // Paper end
         }
-        timings.chunkTicksBlocks.stopTiming(); // Paper
-        gameprofilerfiller.exit();
     }
 
     protected BlockPosition a(BlockPosition blockposition) {
-- 
2.25.1