Profiler-driven performance optimization: CPU profiling, hotspot fixes, and new benchmarks (#7)

Author: Copilot

benchmark/CDT.Benchmarks/Benchmarks.cs

@@ -4,6 +4,7 @@
 
 using BenchmarkDotNet.Attributes;
 using BenchmarkDotNet.Configs;
+using BenchmarkDotNet.Diagnosers;
 using BenchmarkDotNet.Running;
 using CDT;
 
@@ -59,6 +60,7 @@ public static (List<V2d<double>> Vertices, List<Edge> Edges) Read(string fileNam
 /// ~2 600 constraint edges) – the same dataset used in the C++ CDT benchmarks.
 /// </summary>
 [MemoryDiagnoser]
+[EventPipeProfiler(EventPipeProfile.CpuSampling)]
 [GroupBenchmarksBy(BenchmarkLogicalGroupRule.ByCategory)]
 [CategoriesColumn]
 [ShortRunJob]
@@ -127,6 +129,16 @@ public Triangulation<double> Conforming_Auto()
         return cdt;
     }
 
+    [Benchmark(Description = "Conforming – AsProvided")]
+    [BenchmarkCategory("Conforming")]
+    public Triangulation<double> Conforming_AsProvided()
+    {
+        var cdt = new Triangulation<double>(VertexInsertionOrder.AsProvided);
+        cdt.InsertVertices(_vertices);
+        cdt.ConformToEdges(_edges);
+        return cdt;
+    }
+
     // -- Full pipeline (insert + erase outer + holes) ------------------------
 
     [Benchmark(Description = "Full pipeline – Auto")]
@@ -140,6 +152,30 @@ public Triangulation<double> FullPipeline_Auto()
         cdt.EraseOuterTrianglesAndHoles();
         return cdt;
     }
+
+    // -- Finalization APIs (EraseSuperTriangle / EraseOuterTriangles) ---------
+
+    [Benchmark(Description = "EraseSuperTriangle – Auto")]
+    [BenchmarkCategory("Finalization")]
+    public Triangulation<double> EraseSuperTriangle_Auto()
+    {
+        var cdt = new Triangulation<double>(VertexInsertionOrder.Auto);
+        cdt.InsertVertices(_vertices);
+        cdt.InsertEdges(_edges);
+        cdt.EraseSuperTriangle();
+        return cdt;
+    }
+
+    [Benchmark(Description = "EraseOuterTriangles – Auto")]
+    [BenchmarkCategory("Finalization")]
+    public Triangulation<double> EraseOuterTriangles_Auto()
+    {
+        var cdt = new Triangulation<double>(VertexInsertionOrder.Auto);
+        cdt.InsertVertices(_vertices);
+        cdt.InsertEdges(_edges);
+        cdt.EraseOuterTriangles();
+        return cdt;
+    }
 }
 
 // ---------------------------------------------------------------------------
@@ -151,6 +187,7 @@ public Triangulation<double> FullPipeline_Auto()
 /// to measure per-vertex overhead without the noise of large datasets.
 /// </summary>
 [MemoryDiagnoser]
+[EventPipeProfiler(EventPipeProfile.CpuSampling)]
 [GroupBenchmarksBy(BenchmarkLogicalGroupRule.ByCategory)]
 [CategoriesColumn]
 [ShortRunJob]
@@ -206,4 +243,37 @@ public Triangulation<float> FloatVsDouble_Float()
         cdt.InsertEdges(ef);
         return cdt;
     }
+
+    [Benchmark(Description = "Small – Conforming Auto")]
+    [BenchmarkCategory("SmallConforming")]
+    public Triangulation<double> Small_Conforming_Auto()
+    {
+        var cdt = new Triangulation<double>(VertexInsertionOrder.Auto);
+        cdt.InsertVertices(_vertices);
+        cdt.ConformToEdges(_edges);
+        return cdt;
+    }
+
+    [Benchmark(Description = "Small – EraseSuperTriangle Auto")]
+    [BenchmarkCategory("SmallFinalization")]
+    public Triangulation<double> Small_EraseSuperTriangle_Auto()
+    {
+        var cdt = new Triangulation<double>(VertexInsertionOrder.Auto);
+        cdt.InsertVertices(_vertices);
+        cdt.InsertEdges(_edges);
+        cdt.EraseSuperTriangle();
+        return cdt;
+    }
+
+    [Benchmark(Description = "Small – EraseOuterTrianglesAndHoles Auto")]
+    [BenchmarkCategory("SmallFinalization")]
+    public Triangulation<double> Small_EraseOuterTrianglesAndHoles_Auto()
+    {
+        var cdt = new Triangulation<double>(VertexInsertionOrder.Auto,
+            IntersectingConstraintEdges.TryResolve, 0.0);
+        cdt.InsertVertices(_vertices);
+        cdt.InsertEdges(_edges);
+        cdt.EraseOuterTrianglesAndHoles();
+        return cdt;
+    }
 }

src/CDT.Core/KdTree.cs

@@ -55,12 +55,14 @@ public NearestTask(int node, T minX, T minY, T maxX, T maxY, SplitDir dir, T dis
     private T _minX, _minY, _maxX, _maxY;
     private bool _boxInitialized;
     private int _size;
+    private readonly T _two;
 
     private NearestTask[] _stack = new NearestTask[InitialStackDepth];
 
     /// <summary>Initializes an empty KD-tree with no bounding box pre-set.</summary>
     public KdTree()
     {
+        _two = T.One + T.One;
         _minX = T.MinValue; _minY = T.MinValue;
         _maxX = T.MaxValue; _maxY = T.MaxValue;
         _root = AddNewNode();
@@ -70,6 +72,7 @@ public KdTree()
     /// <summary>Initializes an empty KD-tree with a known bounding box.</summary>
     public KdTree(T minX, T minY, T maxX, T maxY)
     {
+        _two = T.One + T.One;
         _minX = minX; _minY = minY; _maxX = maxX; _maxY = maxY;
         _root = AddNewNode();
         _boxInitialized = true;
@@ -226,10 +229,9 @@ private static bool IsInsideBox(T px, T py, T minX, T minY, T maxX, T maxY)
         => px >= minX && px <= maxX && py >= minY && py <= maxY;
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    private static T GetMid(T minX, T minY, T maxX, T maxY, SplitDir dir)
+    private T GetMid(T minX, T minY, T maxX, T maxY, SplitDir dir)
     {
-        T two = T.One + T.One;
-        return dir == SplitDir.X ? (minX + maxX) / two : (minY + maxY) / two;
+        return dir == SplitDir.X ? (minX + maxX) / _two : (minY + maxY) / _two;
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]