Added resizing benchmark results

src/ImageSharp/Formats/Jpeg/Components/Decoder/SpectralConverter.cs

@@ -103,6 +103,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
                 int fullBlocksWidth = (int)((uint)size.Width / blockNativePixelSize);
                 int fullBlocksHeight = (int)((uint)size.Height / blockNativePixelSize);
 
+                // & (blockNativePixelSize - 1) is Numerics.Modulo8(), basically
                 int blockWidthRemainder = size.Width & (blockNativePixelSize - 1);
                 int blockHeightRemainder = size.Height & (blockNativePixelSize - 1);
 

tests/ImageSharp.Benchmarks/LoadResizeSave/LoadResizeSaveStressBenchmarks.cs

@@ -36,7 +36,7 @@ namespace SixLabors.ImageSharp.Benchmarks.LoadResizeSave
 
         public int[] ParallelismValues { get; } =
         {
-            Environment.ProcessorCount,
+            // Environment.ProcessorCount,
             // Environment.ProcessorCount / 2,
             // Environment.ProcessorCount / 4,
             1
@@ -71,3 +71,24 @@ namespace SixLabors.ImageSharp.Benchmarks.LoadResizeSave
         public void NetVips(int maxDegreeOfParallelism) => this.ForEachImage(this.runner.NetVipsResize, maxDegreeOfParallelism);
     }
 }
+
+/*
+BenchmarkDotNet=v0.13.0, OS=Windows 10.0.19044
+Intel Core i7-6700K CPU 4.00GHz (Skylake), 1 CPU, 8 logical and 4 physical cores
+.NET SDK=6.0.300
+  [Host]   : .NET 6.0.5 (6.0.522.21309), X64 RyuJIT
+  ShortRun : .NET 6.0.5 (6.0.522.21309), X64 RyuJIT
+
+Job=ShortRun  IterationCount=3  LaunchCount=1
+WarmupCount=3
+
+|                       Method | maxDegreeOfParallelism |       Mean |       Error |    StdDev | Ratio | RatioSD | Gen 0 | Gen 1 | Gen 2 | Allocated |
+|----------------------------- |----------------------- |-----------:|------------:|----------:|------:|--------:|------:|------:|------:|----------:|
+|                SystemDrawing |                      1 | 3,624.2 ms |   721.39 ms |  39.54 ms |  3.30 |    0.04 |     - |     - |     - |     12 KB |
+|                   ImageSharp |                      1 | 1,098.4 ms |    45.64 ms |   2.50 ms |  1.00 |    0.00 |     - |     - |     - |    717 KB |
+|                       Magick |                      1 | 4,089.8 ms |   905.06 ms |  49.61 ms |  3.72 |    0.04 |     - |     - |     - |     43 KB |
+|                  MagicScaler |                      1 |   888.0 ms |   168.33 ms |   9.23 ms |  0.81 |    0.01 |     - |     - |     - |    105 KB |
+|                   SkiaBitmap |                      1 | 2,934.4 ms | 2,023.43 ms | 110.91 ms |  2.67 |    0.10 |     - |     - |     - |     43 KB |
+| SkiaBitmapDecodeToTargetSize |                      1 |   892.3 ms |   115.54 ms |   6.33 ms |  0.81 |    0.01 |     - |     - |     - |     48 KB |
+|                      NetVips |                      1 |   806.8 ms |    86.23 ms |   4.73 ms |  0.73 |    0.01 |     - |     - |     - |     42 KB |
+*/