using System;
using System.Diagnostics;
using System.Linq;

namespace QuickSort
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var watch = new Stopwatch();
            for (int i = 0; i < 5; i++)
            {
                watch.Restart();
                var vals = Enumerable.Range(0, 1000 * 1000).AsParallel().Select(x => new TestClass()).ToArray();
                watch.Stop();
                Console.WriteLine("Total secs: " + watch.Elapsed.TotalSeconds);
            }
            Console.WriteLine($"GC: {GC.CollectionCount(0)} {GC.CollectionCount(1)} {GC.CollectionCount(2)}");
            Console.ReadLine();
        }
    }

    internal class TestClass
    {
        public string Id = CreateGuid();
        public string Value = CreateGuid();
        private static readonly Random gen = new Random();

        private static string CreateGuid() => gen.Next(100000000).ToString("0000000000");
    }
}

using System;
using System.Diagnostics;
using System.Threading;

namespace QuickSort
{
    public class Program
    {
        private static int threadCount;
        private static ManualResetEvent waitHandle = new ManualResetEvent(false);

        public static void Main(string[] args)
        {
            const int ARRAY_SIZE = 1000 * 1000;
            const int THREADS = 4;

            var watch = new Stopwatch();
            for (var i = 0; i < 5; i++)
            {
                watch.Restart();
                waitHandle.Reset();

                var vals = new TestClass[ARRAY_SIZE];
                for (var j = 0; j < THREADS; j++)
                {
                    int segmentIndex = j;
                    ThreadPool.QueueUserWorkItem(_ => Fill(vals, segmentIndex * (ARRAY_SIZE / THREADS), ARRAY_SIZE / THREADS));
                }
                waitHandle.WaitOne();

                watch.Stop();
                Console.WriteLine($"Total: {watch.ElapsedMilliseconds} ms");
            }
            Console.WriteLine($"GC: {GC.CollectionCount(0)} {GC.CollectionCount(1)} {GC.CollectionCount(2)}");
            Console.ReadLine();
        }

        private static void Fill(TestClass[] array, int start, int count)
        {
            Interlocked.Increment(ref threadCount);

            int end = start + count;
            for (int i = start; i < end; i++)
            {
                array[i] = new TestClass();
            }

            Interlocked.Decrement(ref threadCount);
            if (threadCount == 0)
            {
                waitHandle.Set();
            }
        }
    }

    internal class TestClass
    {
        public string Id = CreateGuid();
        public string Value = CreateGuid();
        private static readonly Random gen = new Random();

        private static string CreateGuid() => gen.Next(100000000).ToString("0000000000");
    }
}