How to use Parallel Loops in C# how it improves performance??

This example shows how to use a Parallel.ForEach loop to enable data parallelism over anySystem.Collections.IEnumerable or System.Collections.Generic.IEnumerable<T> data source.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Diagnostics; namespace ParallelLoopSample { class Program { static void Main(string[] args) { List<string> Large_List1 = new List<string>(); List<string> Large_List2 = new List<string>(); Object myList = new Object(); //Time taken by Loop to Write to List1 var watch1 = Stopwatch.StartNew(); for (Int64 i = 0; i <= 10000000; i++) { Large_List1.Add(i.ToString()); } watch1.Stop(); var elapsedMs = watch1.ElapsedMilliseconds; Console.WriteLine("Total Time Taken to Finish Loop1:{0}", elapsedMs); //Time Taken by Loop to Read List1 and Write to List2 var watch2 = Stopwatch.StartNew(); Parallel.ForEach(Large_List1, new ParallelOptions() { MaxDegreeOfParallelism = 10 }, sel => { try { lock (myList) { Large_List2.Add(sel); } } catch (Exception ex) { Console.WriteLine(ex.ToString()); } }); watch2.Stop(); var elapsedMs2 = watch2.ElapsedMilliseconds; Console.WriteLine("Total Time Taken to Finish Loop2:{0}", elapsedMs2); Console.ReadLine(); } } }

Output: