format-vs-write-perftest.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static int z = 'z';

        static int a = 'a';

        static string MakeRandomString(Random r)
        {
            StringBuilder s = new StringBuilder();
            for (int i = 0; i < r.Next(8, 24); i++)
            {
                s.Append((char)r.Next(a, z));
            }
            return s.ToString();
        }

        static void Main(string[] args)
        {
            const int tries = 100;
            const int stringsCount = 2000000;

#if DEBUG
            Console.WriteLine("Configuration: DEBUG");
#else
            Console.WriteLine("Configuration: RELEASE");
#endif
            Console.WriteLine("Strings Count: " + stringsCount.ToString("n0"));
            Console.WriteLine("Tries: " + tries.ToString("n0"));
            Console.WriteLine();

            Random r = new Random(Seed: 1234);
            string[] randomStrings = new string[stringsCount];
            for (int i = 0; i < stringsCount; i++)
            {
                randomStrings[i] = MakeRandomString(r);
            }

            bool slowmethod = true;

            double slowticks = 0, slowmillis = 0,
                fastticks = 0, fastmillis = 0;

            again:

            long[] millis = new long[tries];
            long[] ticks = new long[tries];

            Stopwatch watch = new Stopwatch();

            MemoryStream stream = new MemoryStream(0);
            StreamWriter writer = new StreamWriter(stream);

            for (int tr = 0; tr < tries; tr++)
            {
                watch.Start();
                foreach (var a in randomStrings)
                {
                    if (slowmethod)
                    {
                        writer.WriteLine("[{0}]", a);
                    }
                    else
                    {
                        writer.Write('[');
                        writer.Write(a);
                        writer.Write(']');
                        writer.Write(writer.NewLine);
                    }
                }
                writer.Flush();
                watch.Stop();
                ticks[tr] = watch.ElapsedTicks;
                millis[tr] = watch.ElapsedMilliseconds;
                watch.Reset();
                stream.Seek(0, SeekOrigin.Begin);
                stream.SetLength(0);
            }

            Console.WriteLine("Method: " + (slowmethod ? "Format" : "Write"));
            Console.WriteLine("Average ticks       : " +  ticks.Average().ToString("N"));
            Console.WriteLine("Average milliseconds: " + millis.Average().ToString("N"));

            if (slowmethod)
            {
                slowticks = ticks.Average();
                slowmillis = millis.Average();
                slowmethod = false;
                goto again;
            }
            else
            {
                fastticks = ticks.Average();
                fastmillis = millis.Average();
            }

            Console.WriteLine("Fast method is {0:p} faster than slow method", 1.0d - fastticks / slowticks);

            Console.ReadLine();
        }
    }
}