TPL APIs are available in the System.Threading and System.Threading.Tasks namespaces. They work around the task, which is a program or a block of code that runs asynchronously. An asynchronous task can be run by calling either the Task.Run or TaskFactory.StartNew methods. When we create a task, we provide a named delegate, anonymous method, or a lambda expression that the task executes.

Here is a code snippet that uses a lambda expression to execute the ExecuteLongRunningTasksmethod using Task.Run:

class Program 
{ 
  static void Main(string[] args) 
  { 
    Task t = Task.Run(()=>ExecuteLongRunningTask(5000)); 
    t.Wait(); 
  } 
 
  public static void ExecuteLongRunningTask(int millis) 
  { 
    Thread.Sleep(millis); 
    Console.WriteLine("Hello World"); 
             
  } 
} 

In the preceding code snippet, we have executed the ExecuteLongRunningTask method asynchronously using the Task.Run method. The Task.Run method returns the Task object that can be used to further wait for the asynchronous piece of code to be executed completely before the program ends. To wait for the task, we have used the Wait method.

Alternatively, we can also use the Task.Factory.StartNew method, which is more advanced and provides more options. While calling the Task.Factory.StartNew method, we can specify CancellationToken, TaskCreationOptions, and TaskScheduler to set the state, specify other options, and schedule tasks.

TPL uses multiple cores of the CPU out of the box. When the task is executed using the TPL API, it automatically splits the task into one or more threads and utilizes multiple processors, if they are available. The decision as to how many threads will be created is calculated at runtime by CLR. Whereas a thread only has an affinity to a single processor, running any task on multiple processors needs a proper manual implementation.