Update JSON platform benchmarks to use JSON source generator

src/BenchmarksApps/Kestrel/PlatformBenchmarks/BenchmarkApplication.Caching.cs

@@ -10,7 +10,11 @@ public partial class BenchmarkApplication
     {
         private async Task Caching(PipeWriter pipeWriter, int count)
         {
+#if NET6_0_OR_GREATER
+            OutputMultipleQueries(pipeWriter, await RawDb.LoadCachedQueries(count), SerializerContext.CachedWorldArray);
+#else
             OutputMultipleQueries(pipeWriter, await RawDb.LoadCachedQueries(count));
+#endif
         }
     }
 }

src/BenchmarksApps/Kestrel/PlatformBenchmarks/BenchmarkApplication.Json.cs

@@ -1,15 +1,21 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
 using System.Buffers;
 using System.Text.Json;
 
 namespace PlatformBenchmarks
 {
     public partial class BenchmarkApplication
     {
-        private readonly static uint _jsonPayloadSize = (uint)JsonSerializer.SerializeToUtf8Bytes(new JsonMessage { message = "Hello, World!" }, SerializerOptions).Length;
+        private readonly static uint _jsonPayloadSize = (uint)JsonSerializer.SerializeToUtf8Bytes(
+            new JsonMessage { message = "Hello, World!" },
+#if NET6_0_OR_GREATER
+            SerializerContext.JsonMessage
+#else
+            SerializerOptions
+#endif
+            ).Length;
 
         private readonly static AsciiString _jsonPreamble =
             _http11OK +
@@ -30,7 +36,15 @@ private static void Json(ref BufferWriter<WriterAdapter> writer, IBufferWriter<b
             utf8JsonWriter.Reset(bodyWriter);
 
             // Body
-            JsonSerializer.Serialize<JsonMessage>(utf8JsonWriter, new JsonMessage { message = "Hello, World!" }, SerializerOptions);
+            JsonSerializer.Serialize(
+                utf8JsonWriter,
+                new JsonMessage { message = "Hello, World!" },
+#if NET6_0_OR_GREATER
+                SerializerContext.JsonMessage
+#else
+                SerializerOptions
+#endif
+                );
         }
     }
 }

src/BenchmarksApps/Kestrel/PlatformBenchmarks/BenchmarkApplication.MultipleQueries.cs

@@ -4,17 +4,28 @@
 using System.IO.Pipelines;
 using System.Text.Json;
 using System.Threading.Tasks;
+#if NET6_0_OR_GREATER
+using System.Text.Json.Serialization.Metadata;
+#endif
 
 namespace PlatformBenchmarks
 {
     public partial class BenchmarkApplication
     {
         private async Task MultipleQueries(PipeWriter pipeWriter, int count)
         {
+#if NET6_0_OR_GREATER
+            OutputMultipleQueries(pipeWriter, await RawDb.LoadMultipleQueriesRows(count), SerializerContext.WorldArray);
+#else
             OutputMultipleQueries(pipeWriter, await RawDb.LoadMultipleQueriesRows(count));
+#endif
         }
 
+#if NET6_0_OR_GREATER
+        private static void OutputMultipleQueries<TWord>(PipeWriter pipeWriter, TWord[] rows, JsonTypeInfo<TWord[]> jsonTypeInfo)
+#else
         private static void OutputMultipleQueries<TWord>(PipeWriter pipeWriter, TWord[] rows)
+#endif
         {
             var writer = GetWriter(pipeWriter, sizeHint: 160 * rows.Length); // in reality it's 152 for one
 
@@ -32,7 +43,15 @@ private static void OutputMultipleQueries<TWord>(PipeWriter pipeWriter, TWord[]
             utf8JsonWriter.Reset(pipeWriter);
 
             // Body
-            JsonSerializer.Serialize<TWord[]>(utf8JsonWriter, rows, SerializerOptions);
+            JsonSerializer.Serialize(
+                utf8JsonWriter,
+                rows,
+#if NET6_0_OR_GREATER
+                jsonTypeInfo
+#else
+                SerializerOptions
+#endif
+                );
 
             // Content-Length
             lengthWriter.WriteNumeric((uint)utf8JsonWriter.BytesCommitted);

src/BenchmarksApps/Kestrel/PlatformBenchmarks/BenchmarkApplication.SingleQuery.cs

@@ -32,7 +32,15 @@ private static void OutputSingleQuery(PipeWriter pipeWriter, World row)
             utf8JsonWriter.Reset(pipeWriter);
 
             // Body
-            JsonSerializer.Serialize<World>(utf8JsonWriter, row, SerializerOptions);
+            JsonSerializer.Serialize(
+                utf8JsonWriter,
+                row,
+#if NET6_0_OR_GREATER
+                SerializerContext.World
+#else
+                SerializerOptions
+#endif
+                );
 
             // Content-Length
             lengthWriter.WriteNumeric((uint)utf8JsonWriter.BytesCommitted);

src/BenchmarksApps/Kestrel/PlatformBenchmarks/BenchmarkApplication.Updates.cs

@@ -32,7 +32,15 @@ private static void OutputUpdates(PipeWriter pipeWriter, World[] rows)
             utf8JsonWriter.Reset(pipeWriter);
 
             // Body
-            JsonSerializer.Serialize<World[]>(utf8JsonWriter, rows, SerializerOptions);
+            JsonSerializer.Serialize(
+                utf8JsonWriter,
+                rows,
+#if NET6_0_OR_GREATER
+                SerializerContext.WorldArray
+#else
+                SerializerOptions
+#endif
+                );
 
             // Content-Length
             lengthWriter.WriteNumeric((uint)utf8JsonWriter.BytesCommitted);

src/BenchmarksApps/Kestrel/PlatformBenchmarks/BenchmarkApplication.cs

@@ -5,6 +5,7 @@
 using System.Buffers.Text;
 using System.IO.Pipelines;
 using System.Text.Json;
+using System.Text.Json.Serialization;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
 
@@ -34,8 +35,6 @@ public partial class BenchmarkApplication
 
         private readonly static AsciiString _plainTextBody = "Hello, World!";
 
-        private static readonly JsonSerializerOptions SerializerOptions = new JsonSerializerOptions();
-
         private readonly static AsciiString _fortunesTableStart = "<!DOCTYPE html><html><head><title>Fortunes</title></head><body><table><tr><th>id</th><th>message</th></tr>";
         private readonly static AsciiString _fortunesRowStart = "<tr><td>";
         private readonly static AsciiString _fortunesColumn = "</td><td>";
@@ -50,6 +49,20 @@ public partial class BenchmarkApplication
         [ThreadStatic]
         private static Utf8JsonWriter t_writer;
 
+#if NET6_0_OR_GREATER
+        private static readonly JsonContext SerializerContext = JsonContext.Default;
+
+        [JsonSourceGenerationOptions(GenerationMode = JsonSourceGenerationMode.Serialization)]
+        [JsonSerializable(typeof(JsonMessage))]
+        [JsonSerializable(typeof(CachedWorld[]))]
+        [JsonSerializable(typeof(World[]))]
+        private partial class JsonContext : JsonSerializerContext
+        {
+        }
+#else
+        private static readonly JsonSerializerOptions SerializerOptions = new();
+#endif
+
         public static class Paths
         {
             public readonly static AsciiString Json = "/json";