Question

I’ve modified Producer/Consumer example http://msdn.microsoft.com/en-us/library/yy12yx1f(v=vs.80).aspx. I don’t want Consumer to process queue “on event”. Instead i’m using infinity loop (the same to one used in Producer) and try to process all elements asap. Are there any problems with such approach? Why we need “events” between Consumer and Producer if we can use infinity loop?

    // Consumer.ThreadRun
    public void ThreadRun()
    {
        int count = 0;
        while (!_syncEvents.ExitThreadEvent.WaitOne(0, false))
        {
            lock (((ICollection)_queue).SyncRoot)
            {
                while (_queue.Count > 0)
                {
                    int item = _queue.Dequeue();
                    count++;
                }
            }
        }
        Console.WriteLine("Consumer Thread: consumed {0} items", count);
    }

Answer 1

I see two potential problems with what you have

1. When the queue is empty your version will sit in a busy loop burning precious CPU, using a event puts the thread to sleep until there is actual work to be done.
2. By locking the queue and processing all the elements in the queue in a single loop like you are doing, you negate the potential benefit of having multiple consumer threads processing the queue. Now because you only increment a count in your example this might not seem like a big deal, but if you start doing real work with the items that you dequeue you could benefit from having multple threads handling that work.

If you are using .NET 4 you might want to take a look at using BlockingCollection(T) Class which would give an even cleaner solution to all of this with less locking to boot.