c# – How do I set the TaskCreationOptions.LongRunning parameter for a normal task?

Question:

Example from andreycha pattern throttling :

public async Task CheckServers()
{
    var servers = new List<string>(10000) { ... };

    const int ConcurrencyLevel = 100;

    // запускаем первые 100 запросов
    var tasks = servers.Take(ConcurrencyLevel).Select(GetVersion).ToList();
    int nextIndex = ConcurrencyLevel;

    while (tasks.Count > 0)
    {
        // дожидаемся завершения любого запроса
        var completedTask = await Task.WhenAny(tasks);

        // удаляем его из списка
        tasks.Remove(completedTask);

        // добавляем новый запрос, если таковые остались
        if (nextIndex < servers.Count)
        {
            tasks.Add(GetVersion(servers[nextIndex++]));
        }

        string rfbVersion = await completedTask;
        // работаем с версией
    }
}

How to set TaskCreationOptions.LongRunning tasks nicely in such an implementation? Is this even possible without using Task.Factory.StartNew ?

Answer:

Look. Let's split Task 'and other asynchronous functions into those that are processor-limited (that is, take up a fixed thread for a long time) and others.

For the first functions, TaskCreationOptions.LongRunning makes sense, TaskCreationOptions.LongRunning we don't want to block a thread from the thread pool for a long time. But such functions are usually provided in the form of synchronous functions that we run through Task.Run . So you can, if you want, run it through Task.Factory.StartNew .

For the rest of the asynchronous functions, there is no concept of "the thread in which the function runs", and most of the time the Task does not run anywhere , just waiting for the await finish. For such functions, TaskCreationOptions.LongRunning meaningless and difficult (if not impossible) to set. But in this case, this option is not needed.