Optimization: Replace CounterIncrementer & PositionUpdater array indexing by direct reference from Accessor (#198)

* Optimization: Replace `CounterIncrementer` & `PositionUpdater` array indexing by direct reference from Accessor

* Move Incrementer init into PackedFieldAccessor ctor

* Remove unnecessary check

* Simplify

Author: SergeiPavlov

Orm/Xtensive.Orm/Tuples/Packed/PackedFieldAccessor.cs

@@ -6,8 +6,11 @@
 
 using System;
 using System.Numerics;
-using System.Data.Common;
+using System.Runtime.CompilerServices;
 using Xtensive.Sql;
+using Counters = Xtensive.Tuples.Packed.TupleLayout.Counters;
+using CounterIncrementer = Xtensive.Tuples.Packed.TupleLayout.CounterIncrementer;
+using PositionUpdater = Xtensive.Tuples.Packed.TupleLayout.PositionUpdater;
 
 namespace Xtensive.Tuples.Packed
 {
@@ -40,6 +43,9 @@ internal abstract class PackedFieldAccessor
     protected readonly long ValueBitMask;
     public readonly byte Index;
 
+    public readonly CounterIncrementer CounterIncrementer;
+    public readonly PositionUpdater PositionUpdater;
+
     public void SetValue<T>(PackedTuple tuple, PackedFieldDescriptor descriptor, bool isNullable, T value)
     {
       if ((isNullable ? NullableSetter : Setter) is SetValueDelegate<T> setter) {
@@ -82,6 +88,13 @@ public abstract bool ValueEquals(PackedTuple left, PackedFieldDescriptor leftDes
 
     public abstract int GetValueHashCode(PackedTuple tuple, PackedFieldDescriptor descriptor);
 
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private void UpdateDescriptorPosition(ref PackedFieldDescriptor descriptor, ref int bitCounter)
+    {
+      descriptor.DataPosition = bitCounter;
+      bitCounter += ValueBitCount;
+    }
+
     protected PackedFieldAccessor(int rank, byte index)
     {
       Rank = rank;
@@ -104,6 +117,26 @@ protected PackedFieldAccessor(int rank, byte index)
       // and then
       // 1000_0000 << 1 = 0000_0000
       ValueBitMask = (1L << (ValueBitCount - 1) << 1) - 1;
+
+      CounterIncrementer = Rank switch {
+        0 => (ref Counters counters) => counters.Val001Counter++,
+        3 => (ref Counters counters) => counters.Val008Counter++,
+        4 => (ref Counters counters) => counters.Val016Counter++,
+        5 => (ref Counters counters) => counters.Val032Counter++,
+        6 => (ref Counters counters) => counters.Val064Counter++,
+        7 => (ref Counters counters) => counters.Val128Counter++,
+        _ => (ref Counters counters) => throw new NotSupportedException(),
+      };
+
+      PositionUpdater = Rank switch {
+        0 => (ref PackedFieldDescriptor descriptor, ref Counters counters) => UpdateDescriptorPosition(ref descriptor, ref counters.Val001Counter),
+        3 => (ref PackedFieldDescriptor descriptor, ref Counters counters) => UpdateDescriptorPosition(ref descriptor, ref counters.Val008Counter),
+        4 => (ref PackedFieldDescriptor descriptor, ref Counters counters) => UpdateDescriptorPosition(ref descriptor, ref counters.Val016Counter),
+        5 => (ref PackedFieldDescriptor descriptor, ref Counters counters) => UpdateDescriptorPosition(ref descriptor, ref counters.Val032Counter),
+        6 => (ref PackedFieldDescriptor descriptor, ref Counters counters) => UpdateDescriptorPosition(ref descriptor, ref counters.Val064Counter),
+        7 => (ref PackedFieldDescriptor descriptor, ref Counters counters) => UpdateDescriptorPosition(ref descriptor, ref counters.Val128Counter),
+        _ => (ref PackedFieldDescriptor descriptor, ref Counters counters) => throw new NotSupportedException()
+      };
     }
   }
 

Orm/Xtensive.Orm/Tuples/Packed/TupleLayout.cs

@@ -20,7 +20,7 @@ internal static class TupleLayout
 
     private const int Val064BitCount = 1 << Val064Rank;
 
-    private ref struct Counters
+    internal ref struct Counters
     {
       public int ObjectCounter;
 
@@ -107,13 +107,11 @@ ValueFieldAccessor ResolveByNullableType(Type type)
       }
     }
 
-    private delegate void CounterIncrementer(ref Counters counters);
+    internal delegate void CounterIncrementer(ref Counters counters);
 
-    private delegate void PositionUpdater(ref PackedFieldDescriptor descriptor, ref Counters counters);
+    internal delegate void PositionUpdater(ref PackedFieldDescriptor descriptor, ref Counters counters);
 
     private static readonly ObjectFieldAccessor ObjectAccessor = new ObjectFieldAccessor();
-    private static readonly CounterIncrementer[] IncrementerByRank;
-    private static readonly PositionUpdater[] PositionUpdaterByRank;
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static void ConfigureFieldAccessor(ref PackedFieldDescriptor descriptor, Type fieldType) =>
@@ -218,76 +216,31 @@ public static void Configure(Type[] fieldTypes, PackedFieldDescriptor[] fieldDes
 
       for (var fieldIndex = 0; fieldIndex < fieldCount; fieldIndex++) {
         ref var descriptor = ref fieldDescriptors[fieldIndex];
-        if (descriptor.IsObjectField()) {
-          continue;
+        if (!descriptor.IsObjectField()) {
+          descriptor.GetAccessor().PositionUpdater(ref descriptor, ref counters);
         }
-
-        PositionUpdaterByRank[descriptor.GetAccessor().Rank].Invoke(ref descriptor, ref counters);
       }
 
       valuesLength = (totalBitCount + (Val064BitCount - 1)) >> Val064Rank;
       objectsLength = counters.ObjectCounter;
     }
 
-    [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    private static void UpdateDescriptorPosition(ref PackedFieldDescriptor descriptor, ref int bitCounter)
-    {
-      descriptor.DataPosition = bitCounter;
-      bitCounter += descriptor.GetAccessor().ValueBitCount;
-    }
-
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     private static void ConfigureFieldPhase1(ref PackedFieldDescriptor descriptor, ref Counters counters,
       Type[] fieldTypes, int fieldIndex)
     {
       descriptor.StatePosition = checked((ushort)(fieldIndex << 1));
 
       ref var fieldType = ref fieldTypes[fieldIndex];
-      var valueAccessor = ValueFieldAccessorResolver.GetValue(fieldType);
-      if (valueAccessor != null) {
+      if (ValueFieldAccessorResolver.GetValue(fieldType) is { } valueAccessor) {
         descriptor.AccessorIndex = valueAccessor.Index;
-
-        IncrementerByRank[valueAccessor.Rank].Invoke(ref counters);
-
+        valueAccessor.CounterIncrementer(ref counters);
         fieldType = valueAccessor.FieldType;
         return;
       }
 
       descriptor.AccessorIndex = ObjectAccessor.Index;
       descriptor.DataPosition = counters.ObjectCounter++;
     }
-
-    static TupleLayout()
-    {
-      IncrementerByRank = new CounterIncrementer[] {
-        (ref Counters counters) => counters.Val001Counter++,
-        (ref Counters counters) => throw new NotSupportedException(),
-        (ref Counters counters) => throw new NotSupportedException(),
-        (ref Counters counters) => counters.Val008Counter++,
-        (ref Counters counters) => counters.Val016Counter++,
-        (ref Counters counters) => counters.Val032Counter++,
-        (ref Counters counters) => counters.Val064Counter++,
-        (ref Counters counters) => counters.Val128Counter++
-      };
-
-      PositionUpdaterByRank = new PositionUpdater[] {
-        (ref PackedFieldDescriptor descriptor, ref Counters counters)
-          => UpdateDescriptorPosition(ref descriptor, ref counters.Val001Counter),
-        (ref PackedFieldDescriptor descriptor, ref Counters counters)
-          => throw new NotSupportedException(),
-        (ref PackedFieldDescriptor descriptor, ref Counters counters)
-          => throw new NotSupportedException(),
-        (ref PackedFieldDescriptor descriptor, ref Counters counters)
-          => UpdateDescriptorPosition(ref descriptor, ref counters.Val008Counter),
-        (ref PackedFieldDescriptor descriptor, ref Counters counters)
-          => UpdateDescriptorPosition(ref descriptor, ref counters.Val016Counter),
-        (ref PackedFieldDescriptor descriptor, ref Counters counters)
-          => UpdateDescriptorPosition(ref descriptor, ref counters.Val032Counter),
-        (ref PackedFieldDescriptor descriptor, ref Counters counters)
-          => UpdateDescriptorPosition(ref descriptor, ref counters.Val064Counter),
-        (ref PackedFieldDescriptor descriptor, ref Counters counters)
-          => UpdateDescriptorPosition(ref descriptor, ref counters.Val128Counter)
-      };
-    }
   }
 }