Improve measure benchmark.

tests/Avalonia.Benchmarks/ControlHierarchyCreator.cs

@@ -0,0 +1,35 @@
+using System.Collections.Generic;
+using Avalonia.Controls;
+
+namespace Avalonia.Benchmarks
+{
+    internal class ControlHierarchyCreator
+    {
+        public static List<Control> CreateChildren(List<Control> controls, IPanel parent, int childCount, int innerCount, int iterations)
+        {
+            for (var i = 0; i < childCount; ++i)
+            {
+                var control = new StackPanel();
+                parent.Children.Add(control);
+
+                for (int j = 0; j < innerCount; ++j)
+                {
+                    var child = new Button();
+
+                    parent.Children.Add(child);
+
+                    controls.Add(child);
+                }
+
+                if (iterations > 0)
+                {
+                    CreateChildren(controls, control, childCount, innerCount, iterations - 1);
+                }
+
+                controls.Add(control);
+            }
+
+            return controls;
+        }
+    }
+}

tests/Avalonia.Benchmarks/Layout/Measure.cs

@@ -1,7 +1,6 @@
-using System;
-using System.Collections.Generic;
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
 using Avalonia.Controls;
-using Avalonia.Layout;
 using Avalonia.UnitTests;
 using BenchmarkDotNet.Attributes;
 
@@ -10,48 +9,34 @@ namespace Avalonia.Benchmarks.Layout
     [MemoryDiagnoser]
     public class Measure
     {
-        private TestRoot root;
-        private List<Control> controls = new List<Control>();
+        private readonly TestRoot _root;
+        private readonly List<Control> _controls = new List<Control>();
 
         public Measure()
         {
             var panel = new StackPanel();
-            root = new TestRoot { Child = panel };
-            controls.Add(panel);
-            CreateChildren(panel, 3, 5);
-            root.LayoutManager.ExecuteInitialLayoutPass(root);
-        }
-
-        [Benchmark]
-        public void Remeasure_Half()
-        {
-            var random = new Random(1);
 
-            foreach (var control in controls)
+            _root = new TestRoot
             {
-                if (random.Next(2) == 0)
-                {
-                    control.InvalidateMeasure();
-                }
-            }
+                Child = panel,
+                Renderer = new NullRenderer()
+            };
 
-            root.LayoutManager.ExecuteLayoutPass();
+            _controls.Add(panel);
+            _controls = ControlHierarchyCreator.CreateChildren(_controls, panel, 3, 5, 5);
+
+            _root.LayoutManager.ExecuteInitialLayoutPass(_root);
         }
 
-        private void CreateChildren(IPanel parent, int childCount, int iterations)
+        [Benchmark, MethodImpl(MethodImplOptions.NoInlining)]
+        public void Remeasure()
         {
-            for (var i = 0; i < childCount; ++i)
+            foreach (var control in _controls)
             {
-                var control = new StackPanel();
-                parent.Children.Add(control);
-
-                if (iterations > 0)
-                {
-                    CreateChildren(control, childCount, iterations - 1);
-                }
-
-                controls.Add(control);
+                control.InvalidateMeasure();
             }
+
+            _root.LayoutManager.ExecuteLayoutPass();
         }
     }
 }

tests/Avalonia.Benchmarks/NullRenderer.cs

@@ -0,0 +1,44 @@
+using System;
+using System.Collections.Generic;
+using Avalonia.Rendering;
+using Avalonia.VisualTree;
+
+namespace Avalonia.Benchmarks
+{
+    internal class NullRenderer : IRenderer
+    {
+        public bool DrawFps { get; set; }
+        public bool DrawDirtyRects { get; set; }
+        public event EventHandler<SceneInvalidatedEventArgs> SceneInvalidated;
+
+        public void AddDirty(IVisual visual)
+        {
+        }
+
+        public void Dispose()
+        {
+        }
+
+        public IEnumerable<IVisual> HitTest(Point p, IVisual root, Func<IVisual, bool> filter) => null;
+
+        public void Paint(Rect rect)
+        {
+        }
+
+        public void RecalculateChildren(IVisual visual)
+        {
+        }
+
+        public void Resized(Size size)
+        {
+        }
+
+        public void Start()
+        {
+        }
+
+        public void Stop()
+        {
+        }
+    }
+}