Redesign benchmarks for culture-specific string operations

src/benchmarks/micro/corefx/System.Globalization/StringEquality.cs

@@ -0,0 +1,70 @@
+// 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 System.Collections.Generic;
+using System.IO;
+using System.IO.Compression;
+using System.Linq;
+
+namespace System.Globalization.Tests
+{
+    [BenchmarkCategory(Categories.CoreFX, Categories.CoreCLR)]
+    public class StringEquality
+    {
+        private string _value, _same, _sameUpper, _diffAtFirstChar;
+
+        public static IEnumerable<(CultureInfo CultureInfo, CompareOptions CompareOptions)> GetOptions()
+        {
+            // Ordinal and OrdinalIgnoreCase use single execution path for all cultures, so we test it only for "en-US"
+            yield return (new CultureInfo("en-US"), CompareOptions.Ordinal);
+            yield return (new CultureInfo("en-US"), CompareOptions.OrdinalIgnoreCase);
+
+            // the most popular culture:
+            yield return (new CultureInfo("en-US"), CompareOptions.None);
+            yield return (new CultureInfo("en-US"), CompareOptions.IgnoreCase);
+
+            // two very common use cases:
+            yield return (CultureInfo.InvariantCulture, CompareOptions.None);
+            yield return (CultureInfo.InvariantCulture, CompareOptions.IgnoreCase);
+
+            // IgnoreSymbols and IgnoreNonSpace are rarely used, this is why we test it only for a single culture
+            yield return (new CultureInfo("en-US"), CompareOptions.IgnoreSymbols);
+            yield return (new CultureInfo("en-US"), CompareOptions.IgnoreNonSpace);
+
+            // Polish language has a lot of special characters, for example 'ch', 'rz', 'sz', 'cz' use two chars to express one ;)
+            // it also has a lot of characters with accent so we use it as an example of a "complex" language
+            yield return (new CultureInfo("pl-PL"), CompareOptions.None);
+        }
+
+        [ParamsSource(nameof(GetOptions))]
+        public (CultureInfo CultureInfo, CompareOptions CompareOptions) Options;
+
+        [Params(1024)] // single execution path = single test case
+        public int Count;
+
+        [GlobalSetup]
+        public void Setup()
+        {
+            // we are using part of Alice's Adventures in Wonderland text as test data
+            char[] characters = File.ReadAllText(CompressedFile.GetFilePath("alice29.txt")).Take(Count).ToArray();
+            _value = new string(characters);
+            _same = new string(characters);
+            _sameUpper = _same.ToUpper();
+            char[] copy = characters.ToArray();
+            copy[0] = (char)(copy[0] + 1);
+            _diffAtFirstChar = new string(copy);
+        }
+
+        [Benchmark] // the most work to do: the strings have same conent, but don't point to the same memory
+        public int Compare_Same() => Options.CultureInfo.CompareInfo.Compare(_value, _same, Options.CompareOptions);
+
+        [Benchmark] // the most work to do for IgnoreCase: every char needs to be compared and uppercased
+        public int Compare_Same_Upper() => Options.CultureInfo.CompareInfo.Compare(_value, _sameUpper, Options.CompareOptions);
+
+        [Benchmark] // this should return quickly
+        public int Compare_DifferentFirstChar() => Options.CultureInfo.CompareInfo.Compare(_value, _diffAtFirstChar, Options.CompareOptions);
+    }
+}

src/benchmarks/micro/corefx/System.Globalization/StringHash.cs

@@ -0,0 +1,46 @@
+// 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 System.Collections.Generic;
+using System.IO;
+using System.IO.Compression;
+using System.Linq;
+
+namespace System.Globalization.Tests
+{
+    [BenchmarkCategory(Categories.CoreFX, Categories.CoreCLR)]
+    public class StringHash
+    {
+        public static IEnumerable<(CultureInfo CultureInfo, CompareOptions CompareOptions)> GetOptions()
+        {
+            // Ordinal and OrdinalIgnoreCase use single execution path for all cultures, so we test it only for "en-US"
+            yield return (new CultureInfo("en-US"), CompareOptions.Ordinal);
+            yield return (new CultureInfo("en-US"), CompareOptions.OrdinalIgnoreCase);
+
+            yield return (new CultureInfo("en-US"), CompareOptions.None);
+            yield return (new CultureInfo("en-US"), CompareOptions.IgnoreCase);
+
+            yield return (CultureInfo.InvariantCulture, CompareOptions.None);
+            yield return (CultureInfo.InvariantCulture, CompareOptions.IgnoreCase);
+        }
+
+        [ParamsSource(nameof(GetOptions))]
+        public (CultureInfo CultureInfo, CompareOptions CompareOptions) Options;
+
+        [Params(
+            128, // small input that fits into stack-allocated array https://github.com/dotnet/coreclr/blob/c6675ef2e22474d6222d054ae3d022c01eda9b6d/src/System.Private.CoreLib/shared/System/Globalization/CompareInfo.Unix.cs#L824
+            1024 * 128)] // medium size input that fits into an array rented from ArrayPool.Shared without allocation
+        public int Count;
+
+        private string _value;
+
+        [GlobalSetup] // we are using part of Alice's Adventures in Wonderland text as test data
+        public void Setup() => _value = new string(File.ReadAllText(CompressedFile.GetFilePath("alice29.txt")).Take(Count).ToArray());
+
+        [Benchmark]
+        public new void GetHashCode() => Options.CultureInfo.CompareInfo.GetHashCode(_value, Options.CompareOptions);
+    }
+}