Add Perf_String_Substring_* benchmarks

src/benchmarks/micro/Serializers/Binary_FromStream.cs

@@ -10,6 +10,7 @@
 
 namespace MicroBenchmarks.Serializers
 {
+#pragma warning disable SYSLIB0011 // BinaryFormatter serialization is obsolete and should not be used.
     [GenericTypeArguments(typeof(LoginViewModel))]
     [GenericTypeArguments(typeof(Location))]
     [GenericTypeArguments(typeof(IndexViewModel))]
@@ -84,4 +85,5 @@ public T MessagePack_()
         [GlobalCleanup]
         public void Cleanup() => memoryStream.Dispose();
     }
+#pragma warning restore SYSLIB0011
 }

src/benchmarks/micro/Serializers/Binary_ToStream.cs

@@ -10,6 +10,7 @@
 
 namespace MicroBenchmarks.Serializers
 {
+#pragma warning disable SYSLIB0011 // BinaryFormatter serialization is obsolete and should not be used.
     [GenericTypeArguments(typeof(LoginViewModel))]
     [GenericTypeArguments(typeof(Location))]
     [GenericTypeArguments(typeof(IndexViewModel))]
@@ -57,4 +58,5 @@ public void MessagePack_()
             MessagePack.MessagePackSerializer.Serialize<T>(memoryStream, value);
         }
     }
+#pragma warning restore SYSLIB0011
 }

src/benchmarks/micro/libraries/System.Runtime.Serialization.Formatters/Perf.BinaryFormatter.cs

@@ -11,6 +11,7 @@
 
 namespace System.Runtime.Serialization.Formatters.Tests
 {
+#pragma warning disable SYSLIB0011 // BinaryFormatter serialization is obsolete and should not be used.
     [BenchmarkCategory(Categories.Libraries, Categories.NoWASM)]
     public class Perf_BinaryFormatter
     {
@@ -47,4 +48,5 @@ public class Book
             public string Id;
         }
     }
+#pragma warning restore SYSLIB0011
 }

src/benchmarks/micro/libraries/System.Runtime/Perf.String.cs

@@ -95,6 +95,7 @@ public string Remove_IntInt(string s, int i1, int i2)
         [Arguments("dzsdzsDDZSDZSDZSddsz", 0)]
         [Arguments("dzsdzsDDZSDZSDZSddsz", 7)]
         [Arguments("dzsdzsDDZSDZSDZSddsz", 10)]
+        [Arguments("dzsdzsDDZSDZSDZSddsz", 19)]
         public string Substring_Int(string s, int i)
             => s.Substring(i);
 
@@ -276,7 +277,63 @@ private static char getStringCharNoInline(string str, int index)
             return str[index];
         }
     }
-
+
+    [BenchmarkCategory(Categories.Runtime, Categories.Libraries)]
+    [DisassemblyDiagnoser(maxDepth: 2, printSource: true, exportHtml: true, exportDiff: true)]
+    public class Perf_String_Substring_Int
+    {
+        const int _length = 16;
+        static readonly string _s = new string('a', _length);
+
+        [ParamsSource(nameof(GetStarts))]
+        public int Start { get; set; }
+
+        public static IEnumerable<int> GetStarts()
+        {
+            yield return 0;
+            yield return _length / 2;
+            yield return _length;
+        }
+
+        [Benchmark]
+        public void Substring() => _s.Substring(Start);
+    }
+
+    [BenchmarkCategory(Categories.Runtime, Categories.Libraries)]
+    [DisassemblyDiagnoser(maxDepth: 2, printSource: true, exportHtml: true, exportDiff: true)]
+    public class Perf_String_Substring_IntInt
+    {
+        const int _length = 16;
+        static readonly string _s = new string('a', _length);
+
+        [ParamsSource(nameof(GetSlices))]
+        public Sub Slice { get; set; }
+
+        public static IEnumerable<Sub> GetSlices()
+        {
+            for (int i = 0; i <= _length / 2; i++)
+            {
+                yield return new() { StartIndex = i, Length = i };
+            }
+            yield return new() { StartIndex = 0, Length = _length };
+        }
+
+        public class Sub
+        {
+            public int StartIndex { get; set; }
+            public int Length { get; set; }
+
+            public override string ToString() => $"I:{StartIndex,2} L:{Length,2}";
+        }
+
+        [Benchmark]
+        public void Substring()
+        {
+            var slice = Slice;
+            _s.Substring(slice.StartIndex, slice.Length);
+        }
+    }
+
     public class StringArguments
     {
         public int Size { get; }