Add base becnhmark

src/ImageSharp/Processing/Processors/Transforms/InterpolatedTransformProcessorBase.cs

@@ -72,7 +72,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
                 for (int i = 0; i < length; i++)
                 {
                     ref float wRef = ref Unsafe.Add(ref weightsRef, i);
-                    wRef = wRef / sum;
+                    wRef /= sum;
                 }
             }
         }
@@ -90,8 +90,7 @@ namespace SixLabors.ImageSharp.Processing.Processors.Transforms
         {
             for (int x = 0, i = sourceMin; i <= sourceMax; i++, x++)
             {
-                float weight = sampler.GetValue(i - point);
-                Unsafe.Add(ref weightsRef, x) = weight;
+                Unsafe.Add(ref weightsRef, x) = sampler.GetValue(i - point);
             }
         }
 

tests/ImageSharp.Benchmarks/Samplers/Rotate.cs

@@ -0,0 +1,39 @@
+using BenchmarkDotNet.Attributes;
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Processing;
+using SixLabors.Primitives;
+
+namespace SixLabors.ImageSharp.Benchmarks.Samplers
+{
+    [Config(typeof(Config.ShortClr))]
+    public class Rotate
+    {
+        [Benchmark]
+        public Size DoRotate()
+        {
+            using (var image = new Image<Rgba32>(Configuration.Default, 400, 400, Rgba32.BlanchedAlmond))
+            {
+                image.Mutate(x => x.Rotate(37.5F));
+
+                return image.Size();
+            }
+        }
+    }
+}
+
+// Nov 4 2018
+//BenchmarkDotNet=v0.10.14, OS=Windows 10.0.17763
+//Intel Core i7-6600U CPU 2.60GHz(Skylake), 1 CPU, 4 logical and 2 physical cores
+//.NET Core SDK = 2.1.403
+
+// [Host]     : .NET Core 2.1.5 (CoreCLR 4.6.26919.02, CoreFX 4.6.26919.02), 64bit RyuJIT
+//  Job-KKDIMW : .NET Framework 4.7.1 (CLR 4.0.30319.42000), 64bit RyuJIT-v4.7.3190.0
+//  Job-IUZRFA : .NET Core 2.1.5 (CoreCLR 4.6.26919.02, CoreFX 4.6.26919.02), 64bit RyuJIT
+
+//LaunchCount=1  TargetCount=3  WarmupCount=3
+
+// #### BEFORE ####:
+//   Method | Runtime |     Mean |     Error |    StdDev | Allocated |
+//--------- |-------- |---------:|----------:|----------:|----------:|
+// DoRotate |     Clr | 85.19 ms | 13.379 ms | 0.7560 ms |      6 KB |
+// DoRotate |    Core | 53.51 ms |  9.512 ms | 0.5375 ms |   4.29 KB |