Tasks in the .NET Queue (Asynchronous / Waiting)

Question

I have a large number of tasks (~ 1000) that need to be completed. I work on a 4-core processor, so I would like to process 4 tasks at the same time, in parallel.

To give you a starting point, here are some sample code.

class Program
{
    public class LongOperation
    {
        private static readonly Random RandomNumberGenerator = new Random(0);
        const int UpdateFrequencyMilliseconds = 100;

        public int CurrentProgress { get; set; }

        public int TargetProcess { get; set; }

        public LongOperation()
        {
            TargetProcess = RandomNumberGenerator.Next(
                (int)TimeSpan.FromSeconds(5).TotalMilliseconds / UpdateFrequencyMilliseconds, 
                (int)TimeSpan.FromSeconds(10).TotalMilliseconds / UpdateFrequencyMilliseconds);
        }

        public async Task Execute()
        {
            while (!IsCompleted)
            {
                await Task.Delay(UpdateFrequencyMilliseconds);
                CurrentProgress++;
            }
        }

        public bool IsCompleted => CurrentProgress >= TargetProcess;
    }

    static void Main(string[] args)
    {
        Task.Factory.StartNew(async () =>
        {
            var operations = new List<LongOperation>();

            for(var x = 1; x <= 10; x++)
                operations.Add(new LongOperation());

            await ProcessOperations(4, operations);
        }).Wait();
    }

    public static async Task ProcessOperations(int maxSimultaneous, List<LongOperation> operations)
    {
        await Task.WhenAll(operations.Select(x => x.Execute()));
        // TODO: Process up to 4 operations at a time, until every operation is completed.
    }
}

I would like to receive information about which classes I will use, and how I would structure ProcessOperationsto process up to 4 operations at a time, until all operations are completed, in one expected Task.

I am thinking about using an object SemaphoreSlimin some way, as it seems to be designed to throttle a resource / process.

Answer 1

, TPL Dataflow library :

// storage
var operations = new BufferBlock<LongOperation>();
// no more than 4 actions at the time
var actions = new ActionBlock<LongOperation>(x => x.Execute(),
    new ExecutionDataflowBlockOptions { MaxDegreeOfParallelism = 4 });

// consume new operations automatically
operations.LinkTo(actions);
for(var x = 1; x <= 10; ++x)
{
    // blocking sending
    operations.Post(new LongOperation());
    // awaitable send for async operations
    // await operations.SendAsync(new LongOperation());
}

, , 30 , BoundedCapacity .