Simple string concat benchmark showing how to get started with BenchmarkDotNet and how to set some basic config

GettingStartedWithBenchmarkDotNet.cs

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Columns;
using BenchmarkDotNet.Configs;
using BenchmarkDotNet.Jobs;
using BenchmarkDotNet.Reports;
using System.Text;

namespace Benchmarks;

[MemoryDiagnoser]
[HideColumns(Column.RatioSD, Column.AllocRatio, Column.Gen0, Column.Gen2)]
[SimpleJob(RuntimeMoniker.Net90)]
[ReturnValueValidator(failOnError: true)] // Validate methods are equivalent
[Config(typeof(Config))] // Custom class to configure BenchmarkDotNet
public class StringBuilderVPlus
{
    private class Config : ManualConfig
    {
        public Config()
        {
            SummaryStyle =
                SummaryStyle.Default
                    .WithRatioStyle(RatioStyle.Trend)
                    .WithTimeUnit(Perfolizer.Horology.TimeUnit.Nanosecond);
        }
    }

    [Params(10, 20)] // Run benchmarks with these parameters
    public int Concats;

    [Benchmark]
    public string StringBuilder()
    {
        StringBuilder stringBuilder = new StringBuilder();

        for (int i = 0; i < Concats; i++)
        {
            stringBuilder.Append("Hello World");
        }

        return stringBuilder.ToString();
    }

    [Benchmark(Baseline = true)]
    public string StringConcatenation()
    {
        string str = "";

        for (int i = 0; i < Concats; i++)
        {
            str += "Hello World";
        }

        return str;
    }
}

public class Program
{
    public static void Main(string[] args)
    {
        BenchmarkRunner.Run<StringBuilderVPlus>();
    }
}