.NET Information center: TPL Performance Improvements in .NET 4.5

Sunday, April 01, 2012

TPL Performance Improvements in .NET 4.5

Task.WaitAll and Task.WaitAny

Task’s waiting logic in .NET 4.5 has been changed. The performance gain for this change is most apparent when waiting on multiple Tasks, such as when using Task.WaitAll and Task.WaitAny.

Let’s explore the extent of this performance boost with this benchmark code for Task.WaitAll:

public static Tuple TestWaitAll(int ntasks)

{
Task[] tasks = new Task[ntasks];
Action action = () => { };
for (int i = 0; i < ntasks; i++) tasks[i] = new Task(action);
Stopwatch sw = new Stopwatch();
long startBytes = GC.GetTotalMemory(true);
sw.Start();
Task.WaitAll(tasks, 1);
sw.Stop();
long endBytes = GC.GetTotalMemory(true);
GC.KeepAlive(tasks);
return Tuple.Create(sw.ElapsedMilliseconds, endBytes - startBytes);

}