Benchmark Dictionary and ConcurrentDictionary

BenchmarkDictAndConcurrentDic.cs

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;
using System.Collections.Concurrent;

var summary = BenchmarkRunner.Run(typeof(Program).Assembly);

class Helper
{
    public static string Repeat(string str, int count)
    {
        return string.Create(str.Length * count, (str, count), (span, state) =>
        {
            var (val, n) = state;
            var span1 = span;
            for (int i = 0; i < n; i++)
            {
                val.AsSpan().CopyTo(span1);
                span1 = span1[val.Length..];
            }
        });
    }
}

public class BenchmarkingA
{
    private Dictionary<string, string> _dic = new Dictionary<string, string>();
    private ConcurrentDictionary<string, string> _currentDic = new ConcurrentDictionary<string, string>();
    private string? testKey;

    [GlobalSetup]
    public void Setup()
    {
        foreach (var i in Enumerable.Range(1, 100))
        {
            string key = Helper.Repeat("Aa", i);
            _dic[key] = key;
            _currentDic[key] = key;
        }
        testKey = Helper.Repeat("Aa", 40);
    }

    [Benchmark(Baseline = true)]
    public string GetDic()
    {
        return _dic[testKey!];
    }

    [Benchmark]
    public string GetCurrectDic()
    {
        return _currentDic[testKey!];
    }
}

result.md

BenchmarkDotNet=v0.13.1, OS=Windows 10.0.19043.1645 (21H1/May2021Update) Intel Core i7-3720QM CPU 2.60GHz (Ivy Bridge), 1 CPU, 8 logical and 4 physical cores .NET SDK=6.0.202 [Host] : .NET 6.0.4 (6.0.422.16404), X64 RyuJIT DefaultJob : .NET 6.0.4 (6.0.422.16404), X64 RyuJIT

Method	Mean	Error	StdDev	Ratio
GetDic	50.36 ns	0.225 ns	0.200 ns	1.00
GetCurrectDic	94.99 ns	0.457 ns	0.405 ns	1.89

BenchmarkDotNet=v0.13.1, OS=Windows 10.0.19044.1645 (21H2) Intel Core i9-10885H CPU 2.40GHz, 1 CPU, 16 logical and 8 physical cores .NET SDK=6.0.202 [Host] : .NET 6.0.4 (6.0.422.16404), X64 RyuJIT DefaultJob : .NET 6.0.4 (6.0.422.16404), X64 RyuJIT

Method	Mean	Error	StdDev	Ratio	RatioSD
GetDic	31.11 ns	0.238 ns	0.222 ns	1.00	0.00
GetCurrectDic	63.61 ns	0.735 ns	0.687 ns	2.04	0.02