c# - Parallel task run with async and await - unable to use multiples cores

Question

I have searched a lot of codes saying that is possible to use multiple cores with parallel async, but none worked. It is always stuck in a single core.

Is it possible?

Bellow it is a code that uses the recommend setting for running task run in multiples cores, but it is not happening.

class Program
{
    static void Main(string[] args)
    {
        Task.Run(async () =>
        {
            var tasks = Enumerable.Range(0, 1000000)
             .Select(i => Console.Out.WriteLineAsync((100000 * 10000).ToString()));

            await Task.WhenAll(tasks);
        }).GetAwaiter().GetResult();
    }
}

Thanks for all the help.

Answer 1

The stream that is being accessed by Console.Out technically exposes asynchronous operations, but it doesn't actually execute any of them asynchronously. All of the asynchronous methods actually do all of their work synchronously, because writing to the console is just so fast that it would take longer to do anything else.

Of course, even if you replaced that operation with an IO operation that actually had an asynchronous implementation (such as network IO) then you're still unlikely to see much CPU usage, because the operation is IO bound. The CPU needs to do nothing more than start the IO operation. If you actually want to see lots of CPU cores doing lots of work, your work needs to be primarily CPU bound work.