TPL数据流线程本地数据 [英] TPL Data Flow Thread Local Data

问题描述

有没有传递线程本地数据转换成ActionBlock，一个很好的方法，例如，如果你在它的DataFlowExecutionOptions指定MaxDegreeOfParallelization是> 1，那么每一个执行行动任务都会有自己的线程本地数据？

下面是我的一些code，它也许会澄清我想要做的：

  VAR选项=新ExecutionDataflowBlockOptions（）
     {
        MaxDegreeOfParallelism = 12
     };

ActionBlock＆LT; INT＆GT; actionBlock =新ActionBlock＆LT; INT＆GT;（的performAction，期权）;

名单＆LT; INT＆GT; resultsList =新的名单，其中，INT＆GT;（）;

的performAction无效（int i）以
{
    //做一些工作

    //将它们添加到resultsList

    //我想请确保执行该方法的每个线程都有
    // resultsList的自己的副本
}
 

我希望能够有ActionBlock调用线程本地初始化函数我公司供应的。事情是这样的：

 新ActionBlock＆LT; INT＆GT;（的performAction，期权，（）=＆gt;新建名单，其中，INT＆GT;（））;
 

和有它通过我的线程本地数据到我的动作功能：

 的performAction无效（INT I，名单，其中，INT＆GT; localUserData）{...}
 

解决方案

我还是不明白，为什么你需要在一个数据流块线程本地列表。你说得对，TDF不具有线程本地值的任何明确的支持（顺便 Parallel.ForEach（）一样）。但是，这并不意味着你不能使用线程局部变量的值，你就必须手工做的一切，用的 的ThreadLocal （我认为 [ThreadStatic] 将无法正常工作在这里，因为它不会让您跟踪的所有线程本地实例）。例如：

 私有静态的ThreadLocal＆LT;列表＆LT; INT＆GT;＆GT; threadLocalList;

私有静态无效的主要（）
{
    threadLocalList =新的ThreadLocal＆LT;列表＆LT; INT＆GT;＆GT;（（）=＆gt;新建名单，其中，INT＆GT;（），TRUE）;

    VAR块=新ActionBlock＆LT; INT＆GT;（
        （动作＆LT; INT＆GT;）的performAction，
        新ExecutionDataflowBlockOptions {MaxDegreeOfParallelism = 4}）;

    的for（int i = 0;我小于10;我++）
        block.Post（ⅰ）;

    block.Complete（）;
    block.Completion.Wait（）;

    的foreach（在threadLocalList.Values​​ VAR名单）
        Console.WriteLine（的string.join（，，列表））;

    threadLocalList.Dispose（）;
}

私有静态无效的performAction（int i）以
{
    threadLocalList.Value.Add（I * I）;
}
 

Is there a good way to pass thread local data into an ActionBlock, such that if you specify MaxDegreeOfParallelization in its DataFlowExecutionOptions to be > 1, then each task that executes the action will have its own thread local data?

Here is some of my code that will perhaps clarify what I want to do:

var options = new ExecutionDataflowBlockOptions() 
     {
        MaxDegreeOfParallelism = 12
     };

ActionBlock<int> actionBlock = new ActionBlock<int>(PerformAction, options);

List<int> resultsList = new List<int>();

void PerformAction(int i)
{
    // do some work

    // add them to resultsList 

    // i want to make sure that each thread that executes this method has its 
    // own copy of resultsList 
}

I want to be able to have the ActionBlock call a thread local init function that I supply. Something like this:

new ActionBlock<int>(PerformAction, options, () => new List<int>()); 

And have it pass my thread local data into my Action function:

void PerformAction(int i, List<int> localUserData) {...}

解决方案

I still don't understand why do you need thread-local list in a dataflow block. And you're right that TDF doesn't have any explicit support for thread-local values (the way Parallel.ForEach() does). But that doesn't mean you can't use thread-local values, you'll just have to do everything manually, using ThreadLocal (I think [ThreadStatic] wouldn't work well here, because it doesn't allow you to track all thread-local instances). For example:

private static ThreadLocal<List<int>> threadLocalList;

private static void Main()
{
    threadLocalList = new ThreadLocal<List<int>>(() => new List<int>(), true);

    var block = new ActionBlock<int>(
        (Action<int>)PerformAction,
        new ExecutionDataflowBlockOptions { MaxDegreeOfParallelism = 4 });

    for (int i = 0; i < 10; i++)
        block.Post(i);

    block.Complete();
    block.Completion.Wait();

    foreach (var list in threadLocalList.Values)
        Console.WriteLine(string.Join(", ", list));

    threadLocalList.Dispose();
}

private static void PerformAction(int i)
{
    threadLocalList.Value.Add(i * i);
}

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