Add benchmarks for (de)serialization using ReferenceHandling.Preserve

src/benchmarks/micro/MicroBenchmarks.csproj

@@ -87,6 +87,11 @@
     <Compile Remove="runtime\PacketTracer\**\*.cs" />
   </ItemGroup>
 
+  <ItemGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' Or ('$(TargetFrameworkIdentifier)' == '.NETCoreApp' And '$(_TargetFrameworkVersionWithoutV)' &lt; '5.0')">
+    <Compile Remove="libraries\System.Text.Json\Serializer\ReadPreservedReferences.cs" />
+    <Compile Remove="libraries\System.Text.Json\Serializer\WritePreservedReferences.cs" />
+  </ItemGroup>
+
   <ItemGroup>
     <!-- Workaround https://github.com/dotnet/project-system/issues/935 -->
     <None Include="**/*.cs" />

src/benchmarks/micro/Serializers/DataGenerator.cs

@@ -35,6 +35,8 @@ internal static T Generate<T>()
                 return (T)(object)CreateXmlElement();
             if (typeof(T) == typeof(SimpleStructWithProperties))
                 return (T)(object)new SimpleStructWithProperties { Num = 1, Text = "Foo" };
+            if (typeof(T) == typeof(SimpleListOfInt))
+                return (T)(object)new SimpleListOfInt { 10, 20, 30 };
             if (typeof(T) == typeof(ClassImplementingIXmlSerialiable))
                 return (T)(object)new ClassImplementingIXmlSerialiable { StringValue = "Hello world" };
             if (typeof(T) == typeof(Dictionary<string, string>))
@@ -361,6 +363,8 @@ public struct SimpleStructWithProperties
         public int Num { get; set; }
         public string Text { get; set; }
     }
+
+    public class SimpleListOfInt : List<int> { }
 
     public class ClassImplementingIXmlSerialiable : IXmlSerializable
     {

src/benchmarks/micro/libraries/System.Text.Json/Serializer/ReadPreservedReferences.cs

@@ -0,0 +1,55 @@
+// 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 BenchmarkDotNet.Attributes;
+using MicroBenchmarks;
+using MicroBenchmarks.Serializers;
+using Newtonsoft.Json;
+
+namespace System.Text.Json.Serialization.Tests
+{
+    [GenericTypeArguments(typeof(LoginViewModel))]
+    [GenericTypeArguments(typeof(Location))]
+    [GenericTypeArguments(typeof(IndexViewModel))]
+    [GenericTypeArguments(typeof(MyEventsListerViewModel))]
+    [GenericTypeArguments(typeof(SimpleListOfInt))]
+    [GenericTypeArguments(typeof(SimpleStructWithProperties))]
+    public class ReadPreservedReferences<T>
+    {
+        [Params(false, true)]
+        public bool IsDataPreserved;
+
+        private string _serialized;
+        private JsonSerializerOptions _options;
+        private JsonSerializerSettings _settings;
+
+        [GlobalSetup]
+        public void Setup()
+        {
+            _options = new JsonSerializerOptions { ReferenceHandling = ReferenceHandling.Preserve };
+
+            _settings = new JsonSerializerSettings { PreserveReferencesHandling = PreserveReferencesHandling.All };
+
+            T value = DataGenerator.Generate<T>();
+
+            if (IsDataPreserved)
+            {
+                _serialized = JsonConvert.SerializeObject(value, _settings);
+            }
+            else
+            {
+                // Use payload that does not contain metadata in order to see what is the penalty of having ReferenceHandling.Preserve set.
+                _serialized = JsonConvert.SerializeObject(value);
+            }
+        }
+
+        [BenchmarkCategory(Categories.Libraries, Categories.JSON)]
+        [Benchmark]
+        public T DeserializePreserved() => JsonSerializer.Deserialize<T>(_serialized, _options);
+
+        [BenchmarkCategory(Categories.ThirdParty, Categories.JSON)]
+        [Benchmark(Baseline = true)]
+        public T NewtonsoftDeserializePreserved() => JsonConvert.DeserializeObject<T>(_serialized, _settings);
+    }    
+}

src/benchmarks/micro/libraries/System.Text.Json/Serializer/WritePreservedReferences.cs

@@ -0,0 +1,42 @@
+// 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 BenchmarkDotNet.Attributes;
+using MicroBenchmarks;
+using MicroBenchmarks.Serializers;
+using Newtonsoft.Json;
+
+namespace System.Text.Json.Serialization.Tests
+{
+    [GenericTypeArguments(typeof(LoginViewModel))]
+    [GenericTypeArguments(typeof(Location))]
+    [GenericTypeArguments(typeof(IndexViewModel))]
+    [GenericTypeArguments(typeof(MyEventsListerViewModel))]
+    [GenericTypeArguments(typeof(SimpleListOfInt))]
+    [GenericTypeArguments(typeof(SimpleStructWithProperties))]
+    public class WritePreservedReferences<T>
+    {
+        private T _value;
+        private JsonSerializerOptions _options;
+        private JsonSerializerSettings _settings;
+
+        [GlobalSetup]
+        public void Setup()
+        {
+            _value = DataGenerator.Generate<T>();
+
+            _options = new JsonSerializerOptions { ReferenceHandling = ReferenceHandling.Preserve };
+
+            _settings = new JsonSerializerSettings { PreserveReferencesHandling = PreserveReferencesHandling.All };
+        }
+
+        [BenchmarkCategory(Categories.Libraries, Categories.JSON)]
+        [Benchmark]
+        public string SerializePreserved() => JsonSerializer.Serialize(_value, _options);
+
+        [BenchmarkCategory(Categories.ThirdParty, Categories.JSON)]
+        [Benchmark(Baseline = true)]
+        public string NewtonsoftSerializePreserved() => JsonConvert.SerializeObject(_value, _settings);
+    }
+}