cast-benchmark.cs

using System;
using System.Collections.Generic;
using BenchmarkDotNet.Attributes;

public class P
{
    static void Main(string[] args)
    {
        BenchmarkDotNet.Running.BenchmarkSwitcher.FromAssembly(typeof(P).Assembly).Run(args);
    }

    public static IEnumerable<object> TestData()
    {
        //yield return new BaseClass();
        //yield return new SubClass3();
        yield return new SubClass6();
    }

    [Benchmark()]
    [ArgumentsSource(nameof(TestData))]
    public bool IsBaseClass(object o) => o is BaseClass;

    [Benchmark()]
    [ArgumentsSource(nameof(TestData))]
    public bool IsSubClass1(object o) => o is SubClass1;

    [Benchmark()]
    [ArgumentsSource(nameof(TestData))]
    public bool IsSubClass2(object o) => o is SubClass2;

    [Benchmark()]
    [ArgumentsSource(nameof(TestData))]
    public bool IsSubClass3(object o) => o is SubClass3;

    [Benchmark()]
    [ArgumentsSource(nameof(TestData))]
    public bool IsSubClass4(object o) => o is SubClass4;

    [Benchmark()]
    [ArgumentsSource(nameof(TestData))]
    public bool IsSubClass5(object o) => o is SubClass5;

    [Benchmark(Baseline = true)]
    [ArgumentsSource(nameof(TestData))]
    public bool IsSubClass6(object o) => o is SubClass6;
}

public class BaseClass : Object { }
public class SubClass1 : BaseClass { }
public class SubClass2 : SubClass1 { }
public class SubClass3 : SubClass2 { }
public class SubClass4 : SubClass3 { }
public class SubClass5 : SubClass4 { }
public class SubClass6 : SubClass5 { }