DictionaryTest.cs

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

namespace DictionaryPerf
{
    [InProcess]
    public class Program
    {
        const int OperationsPerInvoke = 100;
        static Dictionary<int, int> _dictionarySimple;
        static Dictionary<int, int> _dictionaryCollisions;

        [Benchmark(OperationsPerInvoke = OperationsPerInvoke)]
        public bool ContainsKeySimplePositive()
        {
            bool result = false;
            for(var i = 0; i < OperationsPerInvoke; i++)
            {
                result &= _dictionarySimple.ContainsKey(0);
            }
            
            return result;
        }

        [Benchmark(OperationsPerInvoke = OperationsPerInvoke)]
        public bool ContainsKeySimpleNegative()
        {
            bool result = false;
            for (var i = 0; i < OperationsPerInvoke; i++)
            {
                result &= _dictionarySimple.ContainsKey(1);
            }

            return result;
        }

        [Benchmark(OperationsPerInvoke = OperationsPerInvoke)]
        public bool ContainsKeyCollisionPositive()
        {
            bool result = false;
            for (var i = 0; i < OperationsPerInvoke; i++)
            {
                result &= _dictionaryCollisions.ContainsKey(0);
            }

            return result;
        }

        [Benchmark(OperationsPerInvoke = OperationsPerInvoke)]
        public bool ContainsKeyCollisionNegative()
        {
            bool result = false;
            for (var i = 0; i < OperationsPerInvoke; i++)
            {
                result &= _dictionaryCollisions.ContainsKey(49);
            }

            return result;
        }

        public static void Main(string[] args)
        {
            _dictionarySimple = InitalizeSimple();
            _dictionaryCollisions = InitalizeCollisions();

            BenchmarkRunner.Run<Program>();
        }

        static Dictionary<int, int> InitalizeSimple()
        {
            var dict = new Dictionary<int, int>();
            dict.Add(0, 0);
            return dict;
        }

        static Dictionary<int, int> InitalizeCollisions()
        {
            var dict = new Dictionary<int, int>(7);
            dict.Add(0, 0);
            dict.Add(7, 0);
            dict.Add(14, 0);

            dict.Add(21, 0);
            dict.Add(28, 0);
            dict.Add(35, 0);

            dict.Add(42, 0);
            return dict;
        }
    }
}