CorrelationIdGenerator.GenerateId Benchmark

Program.cs

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;
using System;
using System.Runtime.InteropServices;

namespace GenerateIdBenchmark
{
    class Program
    {
        static void Main(string[] args)
        {
            var summary = BenchmarkRunner.Run<Generator>();
        }
    }

    [MemoryDiagnoser]
    public class Generator
    {
        private readonly static long _id = DateTime.UtcNow.Ticks;

        [Benchmark(Baseline = true)]
        public string GenerateId_Origin() => CorrelationIdGenerator_Origin.GenerateId(_id);

        [Benchmark]
        public string GenerateId() => CorrelationIdGenerator.GenerateId(_id);
    }

    internal static class CorrelationIdGenerator_Origin
    {
        // Base32 encoding - in ascii sort order for easy text based sorting
        private static readonly char[] s_encode32Chars = "0123456789ABCDEFGHIJKLMNOPQRSTUV".ToCharArray();


        public static string GenerateId(long id)
        {
            return string.Create(13, id, (buffer, value) =>
            {
                char[] encode32Chars = s_encode32Chars;

                buffer[12] = encode32Chars[value & 31];
                buffer[11] = encode32Chars[(value >> 5) & 31];
                buffer[10] = encode32Chars[(value >> 10) & 31];
                buffer[9] = encode32Chars[(value >> 15) & 31];
                buffer[8] = encode32Chars[(value >> 20) & 31];
                buffer[7] = encode32Chars[(value >> 25) & 31];
                buffer[6] = encode32Chars[(value >> 30) & 31];
                buffer[5] = encode32Chars[(value >> 35) & 31];
                buffer[4] = encode32Chars[(value >> 40) & 31];
                buffer[3] = encode32Chars[(value >> 45) & 31];
                buffer[2] = encode32Chars[(value >> 50) & 31];
                buffer[1] = encode32Chars[(value >> 55) & 31];
                buffer[0] = encode32Chars[(value >> 60) & 31];
            });
        }
    }

    internal static class CorrelationIdGenerator
    {
        // Base32 encoding - in ascii sort order for easy text based sorting
        // 0123456789ABCDEFGHIJKLMNOPQRSTUV
        // use this optimization: https://github.com/dotnet/roslyn/pull/24621
        private static ReadOnlySpan<byte> s_encode32Bytes => new byte[] { (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G', (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N', (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U', (byte)'V' };

        public unsafe static string GenerateId(long id)
        {
            return string.Create(13, id, (buffer, value) =>
            {
                Span<byte> bufferBytes = MemoryMarshal.Cast<char, byte>(buffer);

                // ReadOnlySpan<byte> doesn't support long index, have to use pointer to avoid cast long to int.
                fixed (byte* encode32Bytes = s_encode32Bytes)
                {
                    if (BitConverter.IsLittleEndian)
                    {
                        bufferBytes[24] = encode32Bytes[value & 31];
                        bufferBytes[22] = encode32Bytes[(value >> 5) & 31];
                        bufferBytes[20] = encode32Bytes[(value >> 10) & 31];
                        bufferBytes[18] = encode32Bytes[(value >> 15) & 31];
                        bufferBytes[16] = encode32Bytes[(value >> 20) & 31];
                        bufferBytes[14] = encode32Bytes[(value >> 25) & 31];
                        bufferBytes[12] = encode32Bytes[(value >> 30) & 31];
                        bufferBytes[10] = encode32Bytes[(value >> 35) & 31];
                        bufferBytes[8] = encode32Bytes[(value >> 40) & 31];
                        bufferBytes[6] = encode32Bytes[(value >> 45) & 31];
                        bufferBytes[4] = encode32Bytes[(value >> 50) & 31];
                        bufferBytes[2] = encode32Bytes[(value >> 55) & 31];
                        bufferBytes[0] = encode32Bytes[(value >> 60) & 31];
                    }
                    else
                    {
                        bufferBytes[25] = encode32Bytes[value & 31];
                        bufferBytes[23] = encode32Bytes[(value >> 5) & 31];
                        bufferBytes[21] = encode32Bytes[(value >> 10) & 31];
                        bufferBytes[19] = encode32Bytes[(value >> 15) & 31];
                        bufferBytes[17] = encode32Bytes[(value >> 20) & 31];
                        bufferBytes[15] = encode32Bytes[(value >> 25) & 31];
                        bufferBytes[13] = encode32Bytes[(value >> 30) & 31];
                        bufferBytes[11] = encode32Bytes[(value >> 35) & 31];
                        bufferBytes[9] = encode32Bytes[(value >> 40) & 31];
                        bufferBytes[7] = encode32Bytes[(value >> 45) & 31];
                        bufferBytes[5] = encode32Bytes[(value >> 50) & 31];
                        bufferBytes[3] = encode32Bytes[(value >> 55) & 31];
                        bufferBytes[1] = encode32Bytes[(value >> 60) & 31];
                    }
                }
            });
        }
    }
}

result.txt

// * Summary *

BenchmarkDotNet=v0.11.5, OS=Windows 10.0.18362
Intel Core i7-3720QM CPU 2.60GHz (Ivy Bridge), 1 CPU, 8 logical and 4 physical cores
.NET Core SDK=3.0.100
  [Host]     : .NET Core 3.0.0 (CoreCLR 4.700.19.46205, CoreFX 4.700.19.46214), 64bit RyuJIT
  DefaultJob : .NET Core 3.0.0 (CoreCLR 4.700.19.46205, CoreFX 4.700.19.46214), 64bit RyuJIT


|            Method |     Mean |     Error |    StdDev | Ratio |  Gen 0 | Gen 1 | Gen 2 | Allocated |
|------------------ |---------:|----------:|----------:|------:|-------:|------:|------:|----------:|
| GenerateId_Origin | 18.19 ns | 0.1217 ns | 0.1079 ns |  1.00 | 0.0153 |     - |     - |      48 B |
|        GenerateId | 16.50 ns | 0.0786 ns | 0.0697 ns |  0.91 | 0.0153 |     - |     - |      48 B |