如何在运行时动态更改批处理块的批量大小?

时间:2012-12-07 01:56:24

标签: c# concurrency task-parallel-library tpl-dataflow batching

我在tpl数据流中有一个批处理块,并且有几个目标块链接到批处理块。但是,目标块的数量会动态变化,因此会更改批次的大小。问题是批量大小必须在批量块的初始化时提供,我没有看到稍后调整它的方法。任何想法如何解决这个问题?是取消链接的唯一方法(将所有链接配置为批处理块和批处理块),使用新的批处理大小重新初始化批处理块,然后再次链接?我能做到这一点,但如何确保旧批次和新批次不会混淆不清?

例如,如果我有2个转换块流到批处理块并且现在有一个额外的转换块并希望将批量大小增加到3,那么如何确保处理增加之前的所有先前批处理以确保同步行为?要点是所有变换块都获得完全相同的项目,并且这些变换块的输出应该按照仅匹配相同输入的那些输出进行批处理的方式进行批处理。

以下是我想要的样本:

用于转换块的常量int: 1,2,3,[批量增加的点],4,5,......

让变换块输出他们得到的内容,如1 => 1

所以批处理块应该像这样输出: [1,1],[2,2],[3,3],[批量大小的变化],[4,4,4],[5,5,5],......

这是我目前的代码:

public class Test
{
    private Stopwatch watch;

    private BroadcastBlock<List<InputObject>> tempBCB;
    private BatchBlock<Tuple<List<InputObject>, Dictionary<int, IntermediateObject>>> batchBlock;
    private TransformBlock<Tuple<List<InputObject>, Dictionary<int, IntermediateObject>>[], List<FinalObject>> transformBlock;
    private ActionBlock<List<FinalObject>> justToFlushTransformBlock;

    private CoreLogic core1;
    private CoreLogic core2;

    public Test()
    {
        tempBCB = new BroadcastBlock<List<InputObject>>(input => input);

        //here batch size = 2
        batchBlock = new BatchBlock<Tuple<List<InputObject>,Dictionary<int,IntermediateObject>>>(2, new GroupingDataflowBlockOptions { Greedy = false });

        transformBlock = new TransformBlock<Tuple<List<InputObject>,Dictionary<int,IntermediateObject>>[],List<FinalObject>>(array =>
        {
            List<InputObject> inputObjects = array[0].Item1;
            List<FinalObject> ret = inputObjects.ConvertAll(x => new FinalObject(x));

            foreach (var tuple in array)
            {
                //iterate over each individual object
                foreach (var dictionary in tuple.Item2)
                {
                    ret[dictionary.Key].outputList.Add(dictionary.Value);
                }
            }

            return ret;
        }, new ExecutionDataflowBlockOptions { MaxDegreeOfParallelism = DataflowBlockOptions.Unbounded });

        justToFlushTransformBlock = new ActionBlock<List<FinalObject>>(list =>
            {
                //just in order to accept items from the transformBlock output queue
            });

        //Generate 2 CoreLogic objects
        core1 = new CoreLogic();
        core2 = new CoreLogic();

        //linking
        tempBCB.LinkTo(core1.transformBlock, new DataflowLinkOptions { PropagateCompletion = true });
        tempBCB.LinkTo(core2.transformBlock, new DataflowLinkOptions { PropagateCompletion = true });

        core1.transformBlock.LinkTo(batchBlock);
        core2.transformBlock.LinkTo(batchBlock);

        batchBlock.LinkTo(transformBlock, new DataflowLinkOptions { PropagateCompletion = true });

        transformBlock.LinkTo(justToFlushTransformBlock, new DataflowLinkOptions { PropagateCompletion = true });
    }

    public void Start()
    {
        const int numberChunks = 30;

        watch = new Stopwatch();
        watch.Start();

        for (int j = 1; j <= numberChunks; j++)
        {
            int collectionSize = 10000 * j;

            List<InputObject> collection = new List<InputObject>(collectionSize);
            for (int i = 0; i < collectionSize; i++)
            {
                collection.Add(new InputObject(i));
            }

            tempBCB.Post(collection);
        }

        tempBCB.Complete();

        Task.WhenAll(core1.transformBlock.Completion, core2.transformBlock.Completion).ContinueWith(_ =>
            {
                batchBlock.Complete();
            });

        transformBlock.Completion.Wait();

        watch.Stop();

        Console.WriteLine("Elapsed time (in milliseconds): " + watch.ElapsedMilliseconds);
        Console.ReadLine();
    }
}

public class CoreLogic
{
    private Random rand;
    public TransformBlock<List<InputObject>, Tuple<List<InputObject>, Dictionary<int, IntermediateObject>>> transformBlock;

    public CoreLogic()
    {
        const int numberIntermediateObjects = 10000;

        transformBlock = new TransformBlock<List<InputObject>, Tuple<List<InputObject>, Dictionary<int, IntermediateObject>>>(input =>
        {
            //please ignore the fact that `input` is not utilized here, the point is to generate a collection of IntermediateObject and return

            Dictionary<int, IntermediateObject> ret = new Dictionary<int, IntermediateObject>();
            for (int i = 0; i < numberIntermediateObjects; i++)
            {
                IntermediateObject value = new IntermediateObject(i);

                ret.Add(i, value);
            }

            var tuple = new Tuple<List<InputObject>, Dictionary<int, IntermediateObject>>(input, ret);

            return tuple;
        });
    }
}

public class InputObject : ICloneable
{
    public int value1 { get; private set; }

    public InputObject(int value)
    {
        this.value1 = value;
    }

    object ICloneable.Clone()
    {
        return Clone();
    }

    public InputObject Clone()
    {
        return (InputObject)this.MemberwiseClone();
    }
}

public class IntermediateObject
{
    public int value1 { get; private set; }

    public IntermediateObject(int value)
    {
        this.value1 = value;
    }
}

public class FinalObject
{
    public InputObject input { get; private set; }
    public List<IntermediateObject> outputList;

    public FinalObject(InputObject input)
    {
        this.input = input;

        this.outputList = new List<IntermediateObject>();
    }
}

public static class Cloning
{
    public static List<TValue> CloneListCloneValues<TValue>(List<TValue> original) where TValue : ICloneable
    {
        List<TValue> ret = new List<TValue>(original.Count);

        foreach (TValue entry in original)
        {
            ret.Add((TValue)entry.Clone());
        }

        return ret;
    }
}

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