DeDupeDictionaryEntries-LINQGroupByFirstvsNONLINQ benchamarks

DeDupeDictionaryEntries-LINQGroupByFirstvsNONLINQ.cs

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

namespace Benchmark_ToListCall
{
    [MemoryDiagnoser]
    public class DictionaryBenchmarks
    {
        Dictionary<string, IReadOnlyDictionary<string, uint>> featureExtractors = null;

        [GlobalSetup]
        public void Init()
        {
            IReadOnlyDictionary<string, uint> featureValuesDict1 = new Dictionary<string, uint>(StringComparer.InvariantCultureIgnoreCase)
            {
                { "aaaa",   101 },
                { "foo-50", 202 },
                { "cccc",   301 },
                { "foo-60", 202 }
            };

            var featureValuesDict2 = new Dictionary<string, uint>(StringComparer.InvariantCultureIgnoreCase);

            for (var i = 0; i < 350; i++)
            {
                string str = i.ToString();
                featureValuesDict2.Add($"foo-{str}", (uint)i);
            }

            IReadOnlyDictionary<string, uint> featureValuesDict3 = new Dictionary<string, uint>(StringComparer.InvariantCultureIgnoreCase)
            {
                 { "foo-70",    202 },
                 { "xx",        9999 }
            };

            this.featureExtractors = new Dictionary<string, IReadOnlyDictionary<string, uint>>
            {
                { "featureExtractor1", featureValuesDict1 },
                { "featureExtractor2", featureValuesDict2 },
                { "featureExtractor3", featureValuesDict3 }
            };
        }

        [Benchmark]
        public Dictionary<string, uint> GetDeDupedEntriesUsingGroupByFirst()
        {
            var featureMap = new Dictionary<string, uint>(StringComparer.InvariantCultureIgnoreCase);

            foreach (var featureExtractor in this.featureExtractors)
            {
                var features = featureExtractor.Value;

                if (features == null || !features.Any())
                {
                    continue;
                }

                featureMap = featureMap.Union(features)
                    .GroupBy(g => g.Key)
                    .ToDictionary(pair => pair.Key, pair => pair.First().Value, StringComparer.InvariantCultureIgnoreCase);
            }

            return featureMap;
        }

        [Benchmark]
        public Dictionary<string, uint> GetDeDupedEntriesNonLINQ()
        {

            var featureMap = new Dictionary<string, uint>(StringComparer.InvariantCultureIgnoreCase);

            foreach (var featureExtractor in this.featureExtractors)
            {
                var features = featureExtractor.Value;

                if (features == null || !features.Any())
                {
                    continue;
                }

                foreach (var kp in features)
                {
                    featureMap.TryAdd(kp.Key, kp.Value);
                }
            }

            return featureMap;
        }
    }
}

NonLINQDeDupeBenchamrkResults.md

BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19042
Intel Xeon CPU E5-1650 v4 3.60GHz, 1 CPU, 12 logical and 6 physical cores
.NET Core SDK=5.0.100-rc.2.20479.15
  [Host]     : .NET Core 3.1.9 (CoreCLR 4.700.20.47201, CoreFX 4.700.20.47203), X64 RyuJIT
  DefaultJob : .NET Core 3.1.9 (CoreCLR 4.700.20.47201, CoreFX 4.700.20.47203), X64 RyuJIT

Method	Mean	Error	StdDev	Gen 0	Gen 1	Gen 2	Allocated
GetDeDupedEntriesUsingGroupByFirst	409.42 μs	8.122 μs	14.646 μs	26.8555	4.8828	-	206.99 KB
GetDeDupedEntriesNonLINQ	93.65 μs	1.864 μs	4.357 μs	2.8076	0.2441	-	22.11 KB