DateTime Formatting/Parsing

DateTimeBenchmark

using System;
using System.Buffers.Text;
using System.Globalization;
using System.Text;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

namespace FormatterBenchmark
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            BenchmarkRunner.Run<Benchmark>();
        }
    }

    [MemoryDiagnoser]
    public class Benchmark
    {
        private static readonly DateTime DateTimeValue = DateTime.UtcNow;
        private static readonly char[] DateTimeFormat = {'o'};

        private static readonly string s_DtInput = DateTimeValue.ToString("O");
        private static readonly byte[] s_DtInputArray = Encoding.UTF8.GetBytes(s_DtInput);
        private static readonly byte[] s_Buffer = new byte[40];

        [Benchmark(Description = "Format DateTime CoreCLR")]
        public string CoreClrDateTime()
        {
            var dt = DateTimeValue;
            Span<char> span = stackalloc char[40];
            int pos = 0;
            dt.TryFormat(span, out pos, DateTimeFormat.AsSpan(), CultureInfo.InvariantCulture);
            return span.Slice(0, pos).ToString();
        }

        [Benchmark(Description = "Format DateTime Utf8Formatter")]
        public byte[] Utf8FormatterDateTime()
        {
            var dt = DateTimeValue;
            Span<byte> span = s_Buffer;
            Utf8Formatter.TryFormat(dt, span, out var written);
            return s_Buffer;
        }

        [Benchmark(Description = "Parse DateTime CoreCLR")]
        public DateTime ParseCoreClrDateTime()
        {
            var local = s_DtInput;
            return DateTime.Parse(local.AsSpan(), CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal);
        }

        [Benchmark(Description = "Parse DateTime Utf8Formatter")]
        public DateTime ParseUtf8FormatterDateTime()
        {
            var local = s_DtInputArray;
            Utf8Parser.TryParse(local.AsSpan(), out DateTime value, out int consumed);
            return value;
        }
    }
}