.NET BlockingCollection<T> CPU 用法

Question

运行该程序将在四核系统中消耗 25% CPU 的功率。所以基本上是运行全力以赴。我将范围缩小到消费者，但是负载不会在按下 "x" 时停止，这应该会终止我的消费者。

我的代码

internal class TestBlockingCollectionConsumerProducer2
{
    private int _itemCount;

    internal void Run()
    {
        BlockingCollection<string> blockingCollection = new BlockingCollection<string>();

        // The token source for issuing the cancelation request.
        CancellationTokenSource cts = new CancellationTokenSource();

        // Simple thread waiting for a Console 'x'
        Task.Factory.StartNew(() =>
        {
            if (Console.ReadKey().KeyChar == 'x')
            {
                cts.Cancel();
            }
        });

        // start producer
        Task.Factory.StartNew(() => Produce(blockingCollection, cts.Token));

        // start multiple consumers
        const int THREAD_COUNT = 5;
        for (int i = 0; i < THREAD_COUNT; i++)
        {
            Task.Factory.StartNew(() => Consume(blockingCollection, cts.Token));
        }

        while (true);
    }

    private void Produce(BlockingCollection<string> blockingCollection, CancellationToken cancellationToken)
    {
        while (true)
        {
            for (int i = 0; i < 10; i++)
            {
                blockingCollection.Add(string.Format("Item {0}", _itemCount++), cancellationToken);
            }

            Console.WriteLine("Added 10 items. Current queue length:" + blockingCollection.Count);
            Thread.Sleep(10000);
        }
    }

    private void Consume(BlockingCollection<string> blockingCollection, CancellationToken cancellationToken)
    {
        try
        {
            foreach (string item in blockingCollection.GetConsumingEnumerable(cancellationToken))
            {
                Console.WriteLine(string.Format("[{0}] Consumer: Consuming: {1}", Thread.CurrentThread.ManagedThreadId, item));
                Thread.Sleep(2500);
            }
        }
        catch (OperationCanceledException)
        {
            Console.WriteLine("[{0}] Consumer: Operation has been canceled.", Thread.CurrentThread.ManagedThreadId);
        }
    }
}

My question is:
1. Why is the CPU load so high? Shouldn't GetConsumingEnumerable() block and therefore use no CPU time at all?
2. Why doesn't it stop on cts.Cancel()?

Answer 1

问题不在于 BlockingCollection。

就是和while (true);的死循环。这是在 Run 方法中做什么？那就是燃烧你的 cpu.

我看到 Produce 方法不符合 CancellationToken。您应该使用 while (!cancellationToken.IsCancellationRequested).

而不是无限循环

此外，对于cts.Cancel它确实取消了操作。如果由于某种原因这不起作用，请提供可重现问题的小而完整的程序。

.NET BlockingCollection<T> CPU 用法

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