DictionaryGetWriteValueBenchmark.cs

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Jobs;

namespace Storage.Benchmark.Glo;

[SimpleJob(RuntimeMoniker.Net60)]
[SimpleJob(RuntimeMoniker.NetCoreApp31)]
[SimpleJob(RuntimeMoniker.Net48)]
[MeanColumn]
public class DictionaryGetWriteValueBenchmark
{
    [Benchmark(Baseline = true)]
    public int Dictionary()
    {
        var dictionary = _dictionary;
        var sum = 0;
        foreach (var key in _keys)
        {
            var value = dictionary[key];
            sum += value;

            dictionary[key] = sum;
        }

        return sum;
    }

    [Benchmark]
    public int DictionaryMarshal()
    {
        var dictionary = _dictionary;
        var sum = 0;
        foreach (var key in _keys)
        {
#if NET6_0
            ref var value = ref System.Runtime.InteropServices.CollectionsMarshal.GetValueRefOrNullRef(dictionary, key);
            sum += value;

            value = sum;
#else
            var value = dictionary[key];
            sum += value;

            dictionary[key] = sum;
#endif
        }

        return sum;
    }

    [Benchmark]
    public int Glossary()
    {
        var glossary = _glossary;
        var sum = 0;
        foreach (var key in _keys)
        {
            ref var value = ref glossary.GetValue(key);
            sum += value;

            value = sum;
        }

        return sum;
    }

    #region Configuration

    private Dictionary<int, int> _dictionary = null!;
    private Glossary<int> _glossary;
    private int[] _keys = null!;

    [GlobalSetup]
    public void Init()
    {
        const int count = 1021;

        _dictionary = new Dictionary<int, int>(count);
        _glossary = new Glossary<int>(count);
        _keys = Enumerable.Range(0, count).ToArray();

        for (var i = 0; i < count; i++)
        {
            var number = _keys[i];
            _dictionary.Add(number, number);
            _glossary.Add(number, number);
        }

        Shuffle(_keys, new Random(1234));
    }

    private static void Shuffle<T>(T[] array, Random random)
    {
        var n = array.Length;
        while (n > 1)
        {
            var k = random.Next(n--);
            (array[n], array[k]) = (array[k], array[n]);
        }
    }

    #endregion
}