Add String/StreamReader.ReadToEnd benchmarks (dotnet#2177)

Co-authored-by: Dan Moseley <[email protected]>
Co-authored-by: Adam Sitnik <[email protected]>

Author: 3 people

docs/microbenchmark-design-guidelines.md

@@ -242,6 +242,8 @@ reportedResult = 1/16*SpanCtor + 1*Slice
 
 **Note:** `OperationsPerInvoke` should be big enough to amortize the "setup" cost.
 
+**Tip:** To quickly run your new benchmark just enough to see how long the iterations are, you can add `--iterationCount 1 --warmupCount 0 --invocationCount 1 --unrollFactor 1 --strategy ColdStart` to the end of your command line. It won't give accurate results, but can help you determine whether you need to add more operations to bring the iteration time up to the  100ms goal.
+
 ## Test Cases
 
 ### Code Paths

src/benchmarks/micro/libraries/System.Buffers/Base64Tests.cs

@@ -90,7 +90,7 @@ public void SetupConvertTryFromBase64Chars()
     [WarmupCount(30)] // make sure it's promoted to Tier 1
     public class Base64EncodeDecodeInPlaceTests
     {
-        [Params(1000 * 1000 * 200)] // allows for stable iteraiton around 200ms
+        [Params(1000 * 1000 * 200)] // allows for stable iteration around 200ms
         public int NumberOfBytes { get; set; }
 
         private byte[] _source;

src/benchmarks/micro/libraries/System.Collections/Iterate/IterateFor.cs

@@ -77,7 +77,7 @@ public T List()
             var collection = _list;
             for(int i = 0; i < collection.Count; i++)
                 result = collection[i];
-            return result;;
+            return result;
         }
 
         [GlobalSetup(Target = nameof(IList))]

src/benchmarks/micro/libraries/System.IO/StreamReaderReadLineTests.cs

@@ -28,7 +28,6 @@ public void ReadLine()
             {
                 while (reader.ReadLine() != null) ;
             }
-            
         }
 
         [Benchmark]

src/benchmarks/micro/libraries/System.IO/StreamReaderReadToEndTests.cs

@@ -0,0 +1,47 @@
+// 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.Text;
+using System.Threading.Tasks;
+using BenchmarkDotNet.Attributes;
+using MicroBenchmarks;
+
+namespace System.IO.Tests
+{
+    [BenchmarkCategory(Categories.Libraries)]
+    public class StreamReaderReadToEndTests : TextReaderReadLineTests
+    {
+        private StreamReader _reader;
+
+        [GlobalSetup]
+        public void GlobalSetup()
+        {
+            _text = GenerateLinesText(LineLengthRange, 48 * 1024 * 1024);
+            _reader = new StreamReader(new MemoryStream(Encoding.UTF8.GetBytes(_text)));
+        }
+
+        [GlobalCleanup]
+        public void GlobalCleanup()
+        {
+            _reader?.Dispose();
+        }
+
+        [Benchmark]
+        public string ReadToEnd()
+        {
+            _reader.BaseStream.Position = 0;
+            _reader.DiscardBufferedData();
+            return _reader.ReadToEnd();
+        }
+
+        [Benchmark]
+        [BenchmarkCategory(Categories.NoWASM)]
+        public Task<string> ReadToEndAsync()
+        {
+            _reader.BaseStream.Position = 0;
+            _reader.DiscardBufferedData();
+            return _reader.ReadToEndAsync();
+        }
+    }
+}

src/benchmarks/micro/libraries/System.IO/StringReaderReadToEndTests.cs

@@ -0,0 +1,33 @@
+// 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.Threading.Tasks;
+using BenchmarkDotNet.Attributes;
+using MicroBenchmarks;
+
+namespace System.IO.Tests
+{
+    [BenchmarkCategory(Categories.Libraries)]
+    public class StringReaderReadToEndTests : TextReaderReadLineTests
+    {
+        [GlobalSetup]
+        public void GlobalSetup() => _text = GenerateLinesText(LineLengthRange, 48 * 1024 * 1024);
+
+        [Benchmark]
+        public string ReadToEnd()
+        {
+            // StringReaders cannot be reset, so we are forced to include the constructor in the benchmark
+            using StringReader reader = new StringReader(_text);
+            return reader.ReadToEnd();
+        }
+
+        [BenchmarkCategory(Categories.NoWASM)]
+        [Benchmark]
+        public Task<string> ReadToEndAsync()
+        {
+            using StringReader reader = new StringReader(_text);
+            return reader.ReadToEndAsync();
+        }
+    }
+}