Re-use slot for Add / Remove ops (#266)

Optimisation.

Author: metalgearsloth

src/Arch.Benchmarks/AddRemoveBenchmark.cs

@@ -0,0 +1,45 @@
+using Arch.Core;
+
+namespace Arch.Benchmarks;
+
+[HtmlExporter]
+[MemoryDiagnoser]
+public class AddRemoveBenchmark
+{
+    [Params(10000, 100000, 1000000)] public int Amount;
+
+    private static World _world;
+    private static List<Entity> _entities;
+
+    [GlobalSetup]
+    public void Setup()
+    {
+        _world = World.Create();
+
+        _entities = new List<Entity>(Amount);
+        for (var index = 0; index < Amount; index++)
+        {
+            _entities.Add(_world.Create(new Transform(), new Velocity()));
+        }
+    }
+
+    [Benchmark]
+    public void Add()
+    {
+        for (var index = 0; index < _entities.Count; index++)
+        {
+            var entity = _entities[index];
+            _world.Add<Position2D>(entity);
+        }
+    }
+
+    [Benchmark]
+    public void Remove()
+    {
+        for (var index = 0; index < _entities.Count; index++)
+        {
+            var entity = _entities[index];
+            _world.Remove<Transform>(entity);
+        }
+    }
+}

src/Arch.Benchmarks/Benchmark.cs

@@ -9,7 +9,7 @@ public class Benchmark
 {
     private static void Main(string[] args)
     {
-  /*
+
         // NOTE: Can this be replaced with ManualConfig.CreateEmpty()?
 #pragma warning disable HAA0101 // Array allocation for params parameter
         var config = new ManualConfig()
@@ -18,30 +18,9 @@ private static void Main(string[] args)
             .AddLogger(ConsoleLogger.Default)
             .AddColumnProvider(DefaultColumnProviders.Instance);
 #pragma warning restore HAA0101 // Array allocation for params parameter
-*/
-
-
-        var world = World.Create();
-        world.Create(1_000_00, 10);
-        /*world.Reserve(in Component<int>.Signature, 1_000_00);
-        for (var index = 0; index <= 1_000_00; index++)
-        {
-            world.Create<int>();
-        }*/
-
-        /*
-        var desc = new QueryDescription().WithAll<int>();
-        for (var index = 0; index <= 100000; index++)
-        {
-            world.Query(in desc, (ref int i) =>
-            {
-            });
-        }*/
-
-
 
         // NOTE: Is `-- --job` a typo?
         // Use: dotnet run -c Release --framework net7.0 -- --job short --filter *IterationBenchmark*
-        //BenchmarkSwitcher.FromAssembly(typeof(Benchmark).Assembly).Run(args, config);
+        BenchmarkSwitcher.FromAssembly(typeof(Benchmark).Assembly).Run(args, config);
     }
 }

src/Arch/Buffer/CommandBuffer.cs

@@ -436,15 +436,16 @@ public void Dispose()
 public sealed partial class CommandBuffer
 {
     /// <summary>
-    ///     Adds an list of new components to the <see cref="Entity"/> and moves it to the new <see cref="Archetype"/>.
+    ///     Adds a list of new components to the <see cref="Entity"/> and moves it to the new <see cref="Archetype"/>.
     /// </summary>
     /// <param name="world">The world to operate on.</param>
     /// <param name="entity">The <see cref="Entity"/>.</param>
     /// <param name="components">A <see cref="IList{T}"/> of <see cref="ComponentType"/>'s, those are added to the <see cref="Entity"/>.</param>
     [SkipLocalsInit]
     internal static void AddRange(World world, Entity entity, Span<ComponentType> components)
     {
-        var oldArchetype = world.EntityInfo.GetArchetype(entity.Id);
+        ref var data = ref world.EntityInfo.EntityData[entity.Id];
+        var oldArchetype = data.Archetype;
 
         // BitSet to stack/span bitset, size big enough to contain ALL registered components.
         Span<uint> stack = stackalloc uint[BitSet.RequiredLength(ComponentRegistry.Size)];
@@ -465,6 +466,6 @@ internal static void AddRange(World world, Entity entity, Span<ComponentType> co
             newArchetype = world.GetOrCreate(newSignature);
         }
 
-        world.Move(entity, oldArchetype, newArchetype, out _);
+        world.Move(entity, ref data, oldArchetype, newArchetype, out _);
     }
 }

src/Arch/Core/World.cs

@@ -317,23 +317,29 @@ public Entity Create(in Signature types)
     ///     Moves an <see cref="Entity"/> from one <see cref="Archetype"/> <see cref="Slot"/> to another.
     /// </summary>
     /// <param name="entity">The <see cref="Entity"/>.</param>
+    /// <param name="data">The <see cref="EntityData"/> of the supplied entity.</param>
     /// <param name="source">Its <see cref="Archetype"/>.</param>
     /// <param name="destination">The new <see cref="Archetype"/>.</param>
     /// <param name="destinationSlot">The new <see cref="Slot"/> in which the moved <see cref="Entity"/> will land.</param>
-    internal void Move(Entity entity, Archetype source, Archetype destination, out Slot destinationSlot)
+    internal void Move(Entity entity, ref EntityData data, Archetype source, Archetype destination, out Slot destinationSlot)
     {
+        // Entity should match the supplied EntityData.
+        Debug.Assert(entity == data.Archetype.Entity(ref data.Slot));
+
         // A common mistake, happening in many cases.
         Debug.Assert(source != destination, "From-Archetype is the same as the To-Archetype. Entities cannot move within the same archetype using this function. Probably an attempt was made to attach already existing components to the entity or to remove non-existing ones.");
 
         // Copy entity to other archetype
-        ref var slot = ref EntityInfo.GetSlot(entity.Id);
+        var slot = data.Slot;
         var allocatedEntities = destination.Add(entity, out _, out destinationSlot);
         Archetype.CopyComponents(source, ref slot, destination, ref destinationSlot);
         source.Remove(slot, out var movedEntity);
 
         // Update moved entity from the remove
         EntityInfo.Move(movedEntity, slot);
-        EntityInfo.Move(entity.Id, destination, destinationSlot);
+
+        data.Archetype = destination;
+        data.Slot = destinationSlot;
 
         // Calculate the entity difference between the moved archetypes to allocate more space accordingly.
         Capacity += allocatedEntities;
@@ -1223,11 +1229,12 @@ public ref T AddOrGet<T>(Entity entity, T? component = default)
     [StructuralChange]
     internal void Add<T>(Entity entity, out Archetype newArchetype, out Slot slot)
     {
-        var oldArchetype = EntityInfo.GetArchetype(entity.Id);
+        ref var data = ref EntityInfo.EntityData[entity.Id];
+        var oldArchetype = data.Archetype;
         var type = Component<T>.ComponentType;
         newArchetype = GetOrCreateArchetypeByAddEdge(in type, oldArchetype);
 
-        Move(entity, oldArchetype, newArchetype, out slot);
+        Move(entity, ref data, oldArchetype, newArchetype, out slot);
     }
 
     /// <summary>
@@ -1279,12 +1286,14 @@ public void Add<T>(Entity entity, in T component)
     [StructuralChange]
     public void Remove<T>(Entity entity)
     {
-        var oldArchetype = EntityInfo.GetArchetype(entity.Id);
+        ref var data = ref EntityInfo.EntityData[entity.Id];
+        var oldArchetype = data.Archetype;
+
         var type = Component<T>.ComponentType;
         var newArchetype = GetOrCreateArchetypeByRemoveEdge(in type, oldArchetype);
 
         OnComponentRemoved<T>(entity);
-        Move(entity, oldArchetype, newArchetype, out _);
+        Move(entity, ref data, oldArchetype, newArchetype, out _);
     }
 }
 
@@ -1449,11 +1458,13 @@ public bool TryGet(Entity entity, ComponentType type, out object? component)
     [StructuralChange]
     public void Add(Entity entity, in object cmp)
     {
-        var oldArchetype = EntityInfo.GetArchetype(entity.Id);
+        ref var data = ref EntityInfo.EntityData[entity.Id];
+
+        var oldArchetype = data.Archetype;
         var type = (ComponentType)cmp.GetType();
         var newArchetype = GetOrCreateArchetypeByAddEdge(in type, oldArchetype);
 
-        Move(entity, oldArchetype, newArchetype, out var slot);
+        Move(entity, ref data, oldArchetype, newArchetype, out var slot);
         newArchetype.Set(ref slot, cmp);
         OnComponentAdded(entity, type);
     }
@@ -1470,7 +1481,8 @@ public void Add(Entity entity, in object cmp)
     [StructuralChange]
     public void AddRange(Entity entity, Span<object> components)
     {
-        var oldArchetype = EntityInfo.GetArchetype(entity.Id);
+        ref var data = ref EntityInfo.EntityData[entity.Id];
+        var oldArchetype = data.Archetype;
 
         // BitSet to stack/span bitset, size big enough to contain ALL registered components.
         Span<uint> stack = stackalloc uint[BitSet.RequiredLength(ComponentRegistry.Size)];
@@ -1498,7 +1510,7 @@ public void AddRange(Entity entity, Span<object> components)
         }
 
         // Move and fire events
-        Move(entity, oldArchetype, newArchetype, out var slot);
+        Move(entity, ref data, oldArchetype, newArchetype, out var slot);
         foreach (var cmp in components)
         {
             newArchetype.Set(ref slot, cmp);
@@ -1519,7 +1531,8 @@ public void AddRange(Entity entity, Span<object> components)
     [StructuralChange]
     public void AddRange(Entity entity, Span<ComponentType> components)
     {
-        var oldArchetype = EntityInfo.GetArchetype(entity.Id);
+        ref var data = ref EntityInfo.EntityData[entity.Id];
+        var oldArchetype = data.Archetype;
 
         // BitSet to stack/span bitset, size big enough to contain ALL registered components.
         Span<uint> stack = stackalloc uint[BitSet.RequiredLength(ComponentRegistry.Size)];
@@ -1540,7 +1553,7 @@ public void AddRange(Entity entity, Span<ComponentType> components)
             newArchetype = GetOrCreate(newSignature);
         }
 
-        Move(entity, oldArchetype, newArchetype, out _);
+        Move(entity, ref data, oldArchetype, newArchetype, out _);
 
 #if EVENTS
         for (var i = 0; i < components.Length; i++)
@@ -1561,7 +1574,8 @@ public void AddRange(Entity entity, Span<ComponentType> components)
     [StructuralChange]
     public void Remove(Entity entity, ComponentType type)
     {
-        var oldArchetype = EntityInfo.GetArchetype(entity.Id);
+        ref var data = ref EntityInfo.EntityData[entity.Id];
+        var oldArchetype = data.Archetype;
 
         // BitSet to stack/span bitset, size big enough to contain ALL registered components.
         Span<uint> stack = stackalloc uint[oldArchetype.BitSet.Length];
@@ -1578,7 +1592,7 @@ public void Remove(Entity entity, ComponentType type)
         }
 
         OnComponentRemoved(entity, type);
-        Move(entity, oldArchetype, newArchetype, out _);
+        Move(entity, ref data, oldArchetype, newArchetype, out _);
     }
 
     /// <summary>
@@ -1593,7 +1607,8 @@ public void Remove(Entity entity, ComponentType type)
     [StructuralChange]
     public void RemoveRange(Entity entity, Span<ComponentType> types)
     {
-        var oldArchetype = EntityInfo.GetArchetype(entity.Id);
+        ref var data = ref EntityInfo.EntityData[entity.Id];
+        var oldArchetype = data.Archetype;
 
         // BitSet to stack/span bitset, size big enough to contain ALL registered components.
         Span<uint> stack = stackalloc uint[oldArchetype.BitSet.Length];
@@ -1620,7 +1635,7 @@ public void RemoveRange(Entity entity, Span<ComponentType> types)
             OnComponentRemoved(entity, type);
         }
 
-        Move(entity, oldArchetype, newArchetype, out _);
+        Move(entity, ref data, oldArchetype, newArchetype, out _);
     }
 }