1 files changed, 166 insertions, 0 deletions
diff --git a/src/System.Memory/tests/Performance/Perf.Memory.Span.cs b/src/System.Memory/tests/Performance/Perf.Memory.Span.cs
new file mode 100644
index 0000000000..f2db92e0f4
--- /dev/null
+++ b/src/System.Memory/tests/Performance/Perf.Memory.Span.cs
@@ -0,0 +1,166 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Buffers;
+using System.MemoryTests;
+using Microsoft.Xunit.Performance;
+using Xunit;
+
+namespace System.Memory.Tests
+{
+    public class Perf_Memory_Span
+    {
+        private const int InnerCount = 1_000_000;
+
+        [Benchmark(InnerIterationCount = InnerCount)]
+        public static void SpanFromDefaultIntegerMemory()
+        {
+            Memory<int> memory = default;
+
+            foreach (BenchmarkIteration iteration in Benchmark.Iterations)
+            {
+                using (iteration.StartMeasurement())
+                {
+                    for (int i = 0; i < Benchmark.InnerIterationCount; i++)
+                    {
+                        Span<int> span = memory.Span;
+                    }
+                }
+            }
+        }
+
+        [Benchmark(InnerIterationCount = InnerCount)]
+        public static void SpanFromIntegerArrayBackedMemory()
+        {
+            int[] a = { 91, 92, -93, 94 };
+            var memory = new Memory<int>(a);
+
+            foreach (BenchmarkIteration iteration in Benchmark.Iterations)
+            {
+                using (iteration.StartMeasurement())
+                {
+                    for (int i = 0; i < Benchmark.InnerIterationCount; i++)
+                    {
+                        Span<int> span = memory.Span;
+                    }
+                }
+            }
+        }
+
+        [Benchmark(InnerIterationCount = InnerCount)]
+        public static void SpanFromCharArrayBackedMemory()
+        {
+            char[] a = "9192-9394".ToCharArray();
+            var memory = new Memory<char>(a);
+
+            foreach (BenchmarkIteration iteration in Benchmark.Iterations)
+            {
+                using (iteration.StartMeasurement())
+                {
+                    for (int i = 0; i < Benchmark.InnerIterationCount; i++)
+                    {
+                        Span<char> span = memory.Span;
+                    }
+                }
+            }
+        }
+
+        [Benchmark(InnerIterationCount = InnerCount)]
+        public static void SpanFromObjectArrayBackedMemory()
+        {
+            object o1 = new object();
+            object o2 = new object();
+            object[] a = { o1, o2 };
+            var memory = new Memory<object>(a);
+
+            foreach (BenchmarkIteration iteration in Benchmark.Iterations)
+            {
+                using (iteration.StartMeasurement())
+                {
+                    for (int i = 0; i < Benchmark.InnerIterationCount; i++)
+                    {
+                        Span<object> span = memory.Span;
+                    }
+                }
+            }
+        }
+
+        [Benchmark(InnerIterationCount = InnerCount)]
+        public static void SpanFromStringBackedMemory()
+        {
+            string a = "9192-9394";
+            ReadOnlyMemory<char> memory = a.AsMemory();
+
+            foreach (BenchmarkIteration iteration in Benchmark.Iterations)
+            {
+                using (iteration.StartMeasurement())
+                {
+                    for (int i = 0; i < Benchmark.InnerIterationCount; i++)
+                    {
+                        ReadOnlySpan<char> span = memory.Span;
+                    }
+                }
+            }
+        }
+
+        [Benchmark(InnerIterationCount = InnerCount)]
+        public static void SpanFromIntegerMemoryManager()
+        {
+            int[] a = { 91, 92, -93, 94 };
+            var memory = new Memory<int>(a);
+            MemoryManager<int> manager = new CustomMemoryForTest<int>(a);
+
+            foreach (BenchmarkIteration iteration in Benchmark.Iterations)
+            {
+                using (iteration.StartMeasurement())
+                {
+                    for (int i = 0; i < Benchmark.InnerIterationCount; i++)
+                    {
+                        Span<int> span = manager.Memory.Span;
+                    }
+                }
+            }
+        }
+
+        [Benchmark(InnerIterationCount = InnerCount)]
+        public static void SpanFromCharMemoryManager()
+        {
+            char[] a = "9192-9394".ToCharArray();
+            var memory = new Memory<char>(a);
+            MemoryManager<char> manager = new CustomMemoryForTest<char>(a);
+
+            foreach (BenchmarkIteration iteration in Benchmark.Iterations)
+            {
+                using (iteration.StartMeasurement())
+                {
+                    for (int i = 0; i < Benchmark.InnerIterationCount; i++)
+                    {
+                        Span<char> span = manager.Memory.Span;
+                    }
+                }
+            }
+        }
+
+        [Benchmark(InnerIterationCount = InnerCount)]
+        public static void SpanFromObjectMemoryManager()
+        {
+            object o1 = new object();
+            object o2 = new object();
+            object[] a = { o1, o2 };
+            var memory = new Memory<object>(a);
+            MemoryManager<object> manager = new CustomMemoryForTest<object>(a);
+
+            foreach (BenchmarkIteration iteration in Benchmark.Iterations)
+            {
+                using (iteration.StartMeasurement())
+                {
+                    for (int i = 0; i < Benchmark.InnerIterationCount; i++)
+                    {
+                        Span<object> span = manager.Memory.Span;
+                    }
+                }
+            }
+        }
+    }
+}