From 5d637481bc5bfe46fd57e464b86e9daa20c7696d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=BCnther=20Foidl?= <gue@korporal.at>
Date: Sun, 3 Apr 2022 13:15:06 +0200
Subject: [PATCH] Benchmark for SpanHelpers.Contains

---
 src/benchmarks/micro/MicroBenchmarks.csproj   |  1 +
 .../libraries/System.Memory/SpanHelpers.cs    | 81 +++++++++++++++++++
 2 files changed, 82 insertions(+)
 create mode 100644 src/benchmarks/micro/libraries/System.Memory/SpanHelpers.cs

diff --git a/src/benchmarks/micro/MicroBenchmarks.csproj b/src/benchmarks/micro/MicroBenchmarks.csproj
index 39593a2f9c2..ba1921f5fac 100644
--- a/src/benchmarks/micro/MicroBenchmarks.csproj
+++ b/src/benchmarks/micro/MicroBenchmarks.csproj
@@ -144,6 +144,7 @@
   <ItemGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' Or ('$(TargetFrameworkIdentifier)' == '.NETCoreApp' And '$(_TargetFrameworkVersionWithoutV)' &lt; '6.0')">
     <Compile Remove="libraries\System.Collections\PriorityQueue\Perf_PriorityQueue.cs" />
     <Compile Remove="libraries\Common\AlignedMemory.cs" />
+    <Compile Remove="libraries\System.Memory\SpanHelpers.cs" />
     <Compile Remove="libraries\System.IO.FileSystem\Perf.RandomAccess.cs" />
     <Compile Remove="libraries\System.IO.FileSystem\Perf.RandomAccess.NoBuffering.cs" />
   </ItemGroup>
diff --git a/src/benchmarks/micro/libraries/System.Memory/SpanHelpers.cs b/src/benchmarks/micro/libraries/System.Memory/SpanHelpers.cs
new file mode 100644
index 00000000000..28898f1629c
--- /dev/null
+++ b/src/benchmarks/micro/libraries/System.Memory/SpanHelpers.cs
@@ -0,0 +1,81 @@
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Numerics;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Extensions;
+using MicroBenchmarks;
+
+namespace System.Memory
+{
+    [GenericTypeArguments(typeof(byte))]
+    [GenericTypeArguments(typeof(char))]
+    [BenchmarkCategory(Categories.Runtime, Categories.Libraries, Categories.Span)]
+    [ShortRunJob]
+    public unsafe class SpanHelpers<T>
+        where T : unmanaged, IComparable<T>, IEquatable<T>
+    {
+        private T* _searchSpace;
+        private T _value;
+
+        [ParamsSource(nameof(LengthValues))]
+        public int Length { get; set; }
+
+        public static IEnumerable<object> LengthValues()
+        {
+            // The values for the length take into account the different cut-offs
+            // in the vectorized pathes.
+
+            if (typeof(T) == typeof(byte))
+            {
+                // Vectorization is done on 2 * Vector<byte>.Count => 64 byte elements
+                yield return 63;    // one less the vectorization threshould
+                yield return 64;    // exactly two vectorized operations
+                yield return 65;    // one element more than standard vectorized loop
+                yield return 95;    // one element less than another iteration of the standard vectorized loop
+                yield return 100;
+            }
+            else if (typeof(T) == typeof(char))
+            {
+                // Vectorization is done on 2 * Vector<char>.Count => 32 char elements
+                // Values analogous to the byte values above
+                yield return 31;
+                yield return 32;
+                yield return 33;
+                yield return 47;
+                yield return 100;
+            }
+            else
+            {
+                throw new NotSupportedException();
+            }
+        }
+
+        [GlobalSetup]
+        public void Setup()
+        {
+            _searchSpace = (T*)NativeMemory.AlignedAlloc((uint)Length, 32);
+            Debug.Assert((nint)_searchSpace % Vector<T>.Count == 0);
+            Unsafe.InitBlock(_searchSpace, 0x00, (uint)Length);
+
+            _value = ValuesGenerator.GetNonDefaultValue<T>();
+        }
+
+        [GlobalCleanup]
+        public void Cleanup()
+        {
+            if (_searchSpace != null)
+            {
+                NativeMemory.AlignedFree(_searchSpace);
+                _searchSpace = null;
+            }
+        }
+
+        [Benchmark]
+        public bool Contains()
+        {
+            return new System.Span<T>(_searchSpace, Length).Contains(_value);
+        }
+    }
+}