String Builder Benchmarks

stringbuilder-benchmarks.cs

using System;
using System.Text;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Configs;
using BenchmarkDotNet.Diagnostics.Windows;
using BenchmarkDotNet.Running;

namespace StringBuilderBenchmarks
{
    class Program
    {
        static void Main(string[] args)
        {
            var summary = BenchmarkRunner.Run<StringBuilderBenchmark>();
        }
    }


    [Config(typeof(Config))]
    public class StringBuilderBenchmark
    {
        private class Config : ManualConfig
        {
            public Config()
            {
                Add(new MemoryDiagnoser());
            }
        }

        private readonly string _firstPart = DateTime.Now.ToString("ddd");
        private readonly string _secondPart = DateTime.Now.ToString("MMMM");
        private const int RunCount = 10000;

        [Benchmark]
        public string AppendFormatWithNewLineInFormat()
        {
            var sb = new StringBuilder();
            for (var i = 0; i < RunCount; i++)
            {
                sb.AppendFormat("{0}:{1}{2}", _firstPart, _secondPart, Environment.NewLine);
            }

            return sb.ToString();
        }

        [Benchmark]
        public string AppendFormatWithAppendLine()
        {
            var sb = new StringBuilder();
            for (var i = 0; i < RunCount; i++)
            {
                sb.AppendFormat("{0}:{1}", _firstPart, _secondPart).AppendLine();
            }

            return sb.ToString();
        }

        [Benchmark]
        public string AppendLineWithStringInterpolation()
        {
            var sb = new StringBuilder();
            for (var i = 0; i < RunCount; i++)
            {
                sb.AppendLine($"{_firstPart}:{_secondPart}");
            }

            return sb.ToString();
        }


        [Benchmark]
        public string NaiveAppendFormatLine()
        {
            var sb = new StringBuilder();
            for (var i = 0; i < RunCount; i++)
            {
                sb.NaiveAppendFormatLine("{0}:{1}", _firstPart, _secondPart);
            }

            return sb.ToString();
        }

        [Benchmark]
        public string AppendFormatLine()
        {
            var sb = new StringBuilder();
            for (var i = 0; i < RunCount; i++)
            {
                sb.AppendFormatLine("{0}:{1}", _firstPart, _secondPart);
            }

            return sb.ToString();
        }

        [Benchmark]
        public string AppendFormatWithEscapedNewLine()
        {
            var sb = new StringBuilder();
            for (var i = 0; i < RunCount; i++)
            {
                sb.AppendFormat("{0}:{1}\r\n", _firstPart, _secondPart);
            }

            return sb.ToString();
        }

        [Benchmark]
        public string AppendFormatWithEnvironmentNewLine()
        {
            var sb = new StringBuilder();
            var format = "{0}:{1}" + Environment.NewLine;
            for (var i = 0; i < RunCount; i++)
            {               
                sb.AppendFormat(format, _firstPart, _secondPart);
            }

            return sb.ToString();
        }

    }

    static class StringBuilderExtentions
    {
        public static StringBuilder NaiveAppendFormatLine(this StringBuilder sb, string format, params object[] args)
        {
            // knowing the AppendFormat with AppendLine is going to be generally the fastest
            // without having to rely on hard coding the new line or some verbose code to apply the newline
            // out of the loop an extension method makes sense. But the example you'll see
            // for this is counter-productive (e.g. http://stackoverflow.com/a/18729210/54342) and uses
            // a param array. To do this right we'll need to match all the overloads of stringBuilder.AppendFormat
            // to reduce the number of allocations needed for many cases
            return sb.AppendFormat(format, args).AppendLine();
        }

        public static StringBuilder AppendFormatLine(this StringBuilder sb, string format, object arg0, object arg1)
        {
            return sb.AppendFormat(format, arg0, arg1).AppendLine();
        }
    }
}