TaskScheduler クラス

定義

スレッドのキューにタスクを置くという下位の作業を処理するオブジェクトを表します。Represents an object that handles the low-level work of queuing tasks onto threads.

public ref class TaskScheduler abstract
public abstract class TaskScheduler
type TaskScheduler = class
Public MustInherit Class TaskScheduler
継承
TaskScheduler

次の例は、MSDN コードギャラリー Web サイトの.NET Framework 4 を使用した並列プログラミングのサンプルから抜粋したものです。The following example is taken from the Samples for Parallel Programming with the .NET Framework 4 on the MSDN Code Gallery Web site. アプリによって使用されるスレッドの数を制限するカスタムタスクスケジューラが作成されます。It creates a custom task scheduler that limits the number of threads used by the app. 次に、2つのタスクセットを起動し、タスクおよびタスクが実行されているスレッドに関する情報を表示します。It then launches two sets of tasks and displays information about the task and the thread on which the task is executing.

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

class Example
{
   static void Main()
   {
       // Create a scheduler that uses two threads. 
       LimitedConcurrencyLevelTaskScheduler lcts = new LimitedConcurrencyLevelTaskScheduler(2);
       List<Task> tasks = new List<Task>();
       
       // Create a TaskFactory and pass it our custom scheduler. 
       TaskFactory factory = new TaskFactory(lcts);
       CancellationTokenSource cts = new CancellationTokenSource();
       
       // Use our factory to run a set of tasks. 
       Object lockObj = new Object();
       int outputItem = 0;
       
       for (int tCtr = 0; tCtr <= 4; tCtr++) {
          int iteration = tCtr;
          Task t = factory.StartNew(() => {
                                       for (int i = 0; i < 1000; i++) {
                                          lock (lockObj) {
                                             Console.Write("{0} in task t-{1} on thread {2}   ", 
                                                           i, iteration, Thread.CurrentThread.ManagedThreadId);
                                             outputItem++;
                                             if (outputItem % 3 == 0)
                                                Console.WriteLine();
                                          }
                                       }                   
                                    }, cts.Token);
          tasks.Add(t);                      
      }
      // Use it to run a second set of tasks.                       
      for (int tCtr = 0; tCtr <= 4; tCtr++) {
         int iteration = tCtr;
         Task t1 = factory.StartNew(() => {
                                       for (int outer = 0; outer <= 10; outer++) {
                                          for (int i = 0x21; i <= 0x7E; i++) {
                                             lock (lockObj) {
                                                Console.Write("'{0}' in task t1-{1} on thread {2}   ", 
                                                              Convert.ToChar(i), iteration, Thread.CurrentThread.ManagedThreadId);
                                                outputItem++;
                                                if (outputItem % 3 == 0)
                                                   Console.WriteLine();
                                             } 
                                          }
                                       }                                           
                                    }, cts.Token);           
         tasks.Add(t1);
      }
      
      // Wait for the tasks to complete before displaying a completion message.
      Task.WaitAll(tasks.ToArray());
      cts.Dispose();
      Console.WriteLine("\n\nSuccessful completion.");
   }
}

// Provides a task scheduler that ensures a maximum concurrency level while 
// running on top of the thread pool.
public class LimitedConcurrencyLevelTaskScheduler : TaskScheduler
{
   // Indicates whether the current thread is processing work items.
   [ThreadStatic]
   private static bool _currentThreadIsProcessingItems;

  // The list of tasks to be executed 
   private readonly LinkedList<Task> _tasks = new LinkedList<Task>(); // protected by lock(_tasks)

   // The maximum concurrency level allowed by this scheduler. 
   private readonly int _maxDegreeOfParallelism;

   // Indicates whether the scheduler is currently processing work items. 
   private int _delegatesQueuedOrRunning = 0;

   // Creates a new instance with the specified degree of parallelism. 
   public LimitedConcurrencyLevelTaskScheduler(int maxDegreeOfParallelism)
   {
       if (maxDegreeOfParallelism < 1) throw new ArgumentOutOfRangeException("maxDegreeOfParallelism");
       _maxDegreeOfParallelism = maxDegreeOfParallelism;
   }

   // Queues a task to the scheduler. 
   protected sealed override void QueueTask(Task task)
   {
      // Add the task to the list of tasks to be processed.  If there aren't enough 
      // delegates currently queued or running to process tasks, schedule another. 
       lock (_tasks)
       {
           _tasks.AddLast(task);
           if (_delegatesQueuedOrRunning < _maxDegreeOfParallelism)
           {
               ++_delegatesQueuedOrRunning;
               NotifyThreadPoolOfPendingWork();
           }
       }
   }

   // Inform the ThreadPool that there's work to be executed for this scheduler. 
   private void NotifyThreadPoolOfPendingWork()
   {
       ThreadPool.UnsafeQueueUserWorkItem(_ =>
       {
           // Note that the current thread is now processing work items.
           // This is necessary to enable inlining of tasks into this thread.
           _currentThreadIsProcessingItems = true;
           try
           {
               // Process all available items in the queue.
               while (true)
               {
                   Task item;
                   lock (_tasks)
                   {
                       // When there are no more items to be processed,
                       // note that we're done processing, and get out.
                       if (_tasks.Count == 0)
                       {
                           --_delegatesQueuedOrRunning;
                           break;
                       }

                       // Get the next item from the queue
                       item = _tasks.First.Value;
                       _tasks.RemoveFirst();
                   }

                   // Execute the task we pulled out of the queue
                   base.TryExecuteTask(item);
               }
           }
           // We're done processing items on the current thread
           finally { _currentThreadIsProcessingItems = false; }
       }, null);
   }

   // Attempts to execute the specified task on the current thread. 
   protected sealed override bool TryExecuteTaskInline(Task task, bool taskWasPreviouslyQueued)
   {
       // If this thread isn't already processing a task, we don't support inlining
       if (!_currentThreadIsProcessingItems) return false;

       // If the task was previously queued, remove it from the queue
       if (taskWasPreviouslyQueued) 
          // Try to run the task. 
          if (TryDequeue(task)) 
            return base.TryExecuteTask(task);
          else
             return false; 
       else 
          return base.TryExecuteTask(task);
   }

   // Attempt to remove a previously scheduled task from the scheduler. 
   protected sealed override bool TryDequeue(Task task)
   {
       lock (_tasks) return _tasks.Remove(task);
   }

   // Gets the maximum concurrency level supported by this scheduler. 
   public sealed override int MaximumConcurrencyLevel { get { return _maxDegreeOfParallelism; } }

   // Gets an enumerable of the tasks currently scheduled on this scheduler. 
   protected sealed override IEnumerable<Task> GetScheduledTasks()
   {
       bool lockTaken = false;
       try
       {
           Monitor.TryEnter(_tasks, ref lockTaken);
           if (lockTaken) return _tasks;
           else throw new NotSupportedException();
       }
       finally
       {
           if (lockTaken) Monitor.Exit(_tasks);
       }
   }
}
// The following is a portion of the output from a single run of the example:
//    'T' in task t1-4 on thread 3   'U' in task t1-4 on thread 3   'V' in task t1-4 on thread 3   
//    'W' in task t1-4 on thread 3   'X' in task t1-4 on thread 3   'Y' in task t1-4 on thread 3   
//    'Z' in task t1-4 on thread 3   '[' in task t1-4 on thread 3   '\' in task t1-4 on thread 3   
//    ']' in task t1-4 on thread 3   '^' in task t1-4 on thread 3   '_' in task t1-4 on thread 3   
//    '`' in task t1-4 on thread 3   'a' in task t1-4 on thread 3   'b' in task t1-4 on thread 3   
//    'c' in task t1-4 on thread 3   'd' in task t1-4 on thread 3   'e' in task t1-4 on thread 3   
//    'f' in task t1-4 on thread 3   'g' in task t1-4 on thread 3   'h' in task t1-4 on thread 3   
//    'i' in task t1-4 on thread 3   'j' in task t1-4 on thread 3   'k' in task t1-4 on thread 3   
//    'l' in task t1-4 on thread 3   'm' in task t1-4 on thread 3   'n' in task t1-4 on thread 3   
//    'o' in task t1-4 on thread 3   'p' in task t1-4 on thread 3   ']' in task t1-2 on thread 4   
//    '^' in task t1-2 on thread 4   '_' in task t1-2 on thread 4   '`' in task t1-2 on thread 4   
//    'a' in task t1-2 on thread 4   'b' in task t1-2 on thread 4   'c' in task t1-2 on thread 4   
//    'd' in task t1-2 on thread 4   'e' in task t1-2 on thread 4   'f' in task t1-2 on thread 4   
//    'g' in task t1-2 on thread 4   'h' in task t1-2 on thread 4   'i' in task t1-2 on thread 4   
//    'j' in task t1-2 on thread 4   'k' in task t1-2 on thread 4   'l' in task t1-2 on thread 4   
//    'm' in task t1-2 on thread 4   'n' in task t1-2 on thread 4   'o' in task t1-2 on thread 4   
//    'p' in task t1-2 on thread 4   'q' in task t1-2 on thread 4   'r' in task t1-2 on thread 4   
//    's' in task t1-2 on thread 4   't' in task t1-2 on thread 4   'u' in task t1-2 on thread 4   
//    'v' in task t1-2 on thread 4   'w' in task t1-2 on thread 4   'x' in task t1-2 on thread 4   
//    'y' in task t1-2 on thread 4   'z' in task t1-2 on thread 4   '{' in task t1-2 on thread 4   
//    '|' in task t1-2 on thread 4   '}' in task t1-2 on thread 4   '~' in task t1-2 on thread 4   
//    'q' in task t1-4 on thread 3   'r' in task t1-4 on thread 3   's' in task t1-4 on thread 3   
//    't' in task t1-4 on thread 3   'u' in task t1-4 on thread 3   'v' in task t1-4 on thread 3   
//    'w' in task t1-4 on thread 3   'x' in task t1-4 on thread 3   'y' in task t1-4 on thread 3   
//    'z' in task t1-4 on thread 3   '{' in task t1-4 on thread 3   '|' in task t1-4 on thread 3  
Imports System.Collections.Generic
Imports System.Threading
Imports System.Threading.Tasks

Module Example
   Sub Main()
      ' Create a scheduler that uses two threads. 
      Dim lcts As New LimitedConcurrencyLevelTaskScheduler(2)
      Dim tasks As New List(Of Task)()
      
      ' Create a TaskFactory and pass it our custom scheduler. 
      Dim factory As New TaskFactory(lcts)
      Dim cts As New CancellationTokenSource()
      
      ' Use our factory to run a set of tasks. 
      Dim objLock As New Object()      
      Dim outputItem As Integer 
      For tCtr As Integer = 0 To 4
         Dim iteration As Integer = tCtr
         Dim t As Task = factory.StartNew(Sub()
                                             For i As Integer = 1 To 1000
                                                SyncLock objLock
                                                   Console.Write("{0} in task t-{1} on thread {2}   ", 
                                                   i, iteration, Thread.CurrentThread.ManagedThreadId)
                                                   outputItem += 1
                                                   If outputItem Mod 3 = 0 Then Console.WriteLine()
                                                End SyncLock
                                             Next 
                                          End Sub,
                                cts.Token)
         tasks.Add(t)
      Next 
      ' Use it to run a second set of tasks.                       
      For tCtr As Integer = 0 To 4
         Dim iteration As Integer = tCtr
         Dim t1 As Task = factory.StartNew(Sub()
                                              For outer As Integer = 0 To 10
                                                 For i As Integer = &h21 To &h7E
                                                    SyncLock objLock
                                                       Console.Write("'{0}' in task t1-{1} on thread {2}   ", 
                                                                     Convert.ToChar(i), iteration, Thread.CurrentThread.ManagedThreadId)
                                                       outputItem += 1
                                                       If outputItem Mod 3 = 0 Then Console.WriteLine()
                                                    End SyncLock 
                                                 Next     
                                              Next                                           
                                           End Sub,
                                cts.Token)           
         tasks.Add(t1)
      Next
      
      ' Wait for the tasks to complete before displaying a completion message.
      Task.WaitAll(tasks.ToArray())
      cts.Dispose()
      Console.WriteLine(vbCrLf + vbCrLf + "Successful completion.")
   End Sub 
End Module

' Provides a task scheduler that ensures a maximum concurrency level while 
' running on top of the thread pool.
Public Class LimitedConcurrencyLevelTaskScheduler : Inherits TaskScheduler
   ' Indicates whether the current thread is processing work items.
   <ThreadStatic()> Private Shared _currentThreadIsProcessingItems As Boolean 
   
   ' The list of tasks to be executed 
   Private ReadOnly _tasks As LinkedList(Of Task) = New LinkedList(Of Task)() 
   
   'The maximum concurrency level allowed by this scheduler. 
   Private ReadOnly _maxDegreeOfParallelism As Integer 
   
   ' Indicates whether the scheduler is currently processing work items. 
   Private _delegatesQueuedOrRunning As Integer = 0 ' protected by lock(_tasks)
   
   ' Creates a new instance with the specified degree of parallelism. 
   Public Sub New(ByVal maxDegreeOfParallelism As Integer)
      If (maxDegreeOfParallelism < 1) Then 
         Throw New ArgumentOutOfRangeException("maxDegreeOfParallelism")
      End If
         _maxDegreeOfParallelism = maxDegreeOfParallelism
   End Sub 

   ' Queues a task to the scheduler. 
   Protected Overrides Sub QueueTask(ByVal t As Task)
      ' Add the task to the list of tasks to be processed.  If there aren't enough 
      ' delegates currently queued or running to process tasks, schedule another. 
      SyncLock (_tasks)
         _tasks.AddLast(t)
         If (_delegatesQueuedOrRunning < _maxDegreeOfParallelism) Then
            _delegatesQueuedOrRunning = _delegatesQueuedOrRunning + 1
            NotifyThreadPoolOfPendingWork()
         End If 
      End SyncLock 
   End Sub 
   
   ' Inform the ThreadPool that there's work to be executed for this scheduler. 
   Private Sub NotifyThreadPoolOfPendingWork()
   
      ThreadPool.UnsafeQueueUserWorkItem(Sub()
                                            ' Note that the current thread is now processing work items. 
                                            ' This is necessary to enable inlining of tasks into this thread.
                                            _currentThreadIsProcessingItems = True 
                                            Try 
                                               ' Process all available items in the queue. 
                                               While (True)
                                                  Dim item As Task
                                                  SyncLock (_tasks)
                                                     ' When there are no more items to be processed, 
                                                     ' note that we're done processing, and get out. 
                                                     If (_tasks.Count = 0) Then
                                                        _delegatesQueuedOrRunning = _delegatesQueuedOrRunning - 1
                                                        Exit While 
                                                     End If 
   
                                                     ' Get the next item from the queue
                                                     item = _tasks.First.Value
                                                     _tasks.RemoveFirst()
                                                  End SyncLock 
   
                                                  ' Execute the task we pulled out of the queue 
                                                  MyBase.TryExecuteTask(item)
                                               End While 
                                               ' We're done processing items on the current thread 
                                            Finally
                                               _currentThreadIsProcessingItems = False 
                                            End Try 
                                         End Sub,
                                    Nothing)
   End Sub 
   
   ' Attempts to execute the specified task on the current thread. 
   Protected Overrides Function TryExecuteTaskInline(ByVal t As Task, 
                                                     ByVal taskWasPreviouslyQueued As Boolean) As Boolean 
      ' If this thread isn't already processing a task, we don't support inlining 
      If (Not _currentThreadIsProcessingItems) Then 
         Return False 
      End If 
   
      ' If the task was previously queued, remove it from the queue 
      If (taskWasPreviouslyQueued) Then
         ' Try to run the task. 
         If TryDequeue(t) Then 
            Return MyBase.TryExecuteTask(t)
         Else
            Return False 
         End If     
      Else 
         Return MyBase.TryExecuteTask(t)
      End If   
   End Function 
   
   ' Attempt to remove a previously scheduled task from the scheduler. 
   Protected Overrides Function TryDequeue(ByVal t As Task) As Boolean 
      SyncLock (_tasks)
         Return _tasks.Remove(t)
      End SyncLock 
   End Function 
   
   ' Gets the maximum concurrency level supported by this scheduler. 
   Public Overrides ReadOnly Property MaximumConcurrencyLevel As Integer 
      Get 
         Return _maxDegreeOfParallelism
      End Get 
   End Property 
   
   ' Gets an enumerable of the tasks currently scheduled on this scheduler. 
   Protected Overrides Function GetScheduledTasks() As IEnumerable(Of Task)
      Dim lockTaken As Boolean = False 
      Try
         Monitor.TryEnter(_tasks, lockTaken)
         If (lockTaken) Then 
            Return _tasks.ToArray()
         Else 
            Throw New NotSupportedException()
         End If 
      Finally 
         If (lockTaken) Then
            Monitor.Exit(_tasks)
         End If 
      End Try 
   End Function 
End Class 
' The following is a portion of the output from a single run of the example:
'    'T' in task t1-4 on thread 3   'U' in task t1-4 on thread 3   'V' in task t1-4 on thread 3   
'    'W' in task t1-4 on thread 3   'X' in task t1-4 on thread 3   'Y' in task t1-4 on thread 3   
'    'Z' in task t1-4 on thread 3   '[' in task t1-4 on thread 3   '\' in task t1-4 on thread 3   
'    ']' in task t1-4 on thread 3   '^' in task t1-4 on thread 3   '_' in task t1-4 on thread 3   
'    '`' in task t1-4 on thread 3   'a' in task t1-4 on thread 3   'b' in task t1-4 on thread 3   
'    'c' in task t1-4 on thread 3   'd' in task t1-4 on thread 3   'e' in task t1-4 on thread 3   
'    'f' in task t1-4 on thread 3   'g' in task t1-4 on thread 3   'h' in task t1-4 on thread 3   
'    'i' in task t1-4 on thread 3   'j' in task t1-4 on thread 3   'k' in task t1-4 on thread 3   
'    'l' in task t1-4 on thread 3   'm' in task t1-4 on thread 3   'n' in task t1-4 on thread 3   
'    'o' in task t1-4 on thread 3   'p' in task t1-4 on thread 3   ']' in task t1-2 on thread 4   
'    '^' in task t1-2 on thread 4   '_' in task t1-2 on thread 4   '`' in task t1-2 on thread 4   
'    'a' in task t1-2 on thread 4   'b' in task t1-2 on thread 4   'c' in task t1-2 on thread 4   
'    'd' in task t1-2 on thread 4   'e' in task t1-2 on thread 4   'f' in task t1-2 on thread 4   
'    'g' in task t1-2 on thread 4   'h' in task t1-2 on thread 4   'i' in task t1-2 on thread 4   
'    'j' in task t1-2 on thread 4   'k' in task t1-2 on thread 4   'l' in task t1-2 on thread 4   
'    'm' in task t1-2 on thread 4   'n' in task t1-2 on thread 4   'o' in task t1-2 on thread 4   
'    'p' in task t1-2 on thread 4   'q' in task t1-2 on thread 4   'r' in task t1-2 on thread 4   
'    's' in task t1-2 on thread 4   't' in task t1-2 on thread 4   'u' in task t1-2 on thread 4   
'    'v' in task t1-2 on thread 4   'w' in task t1-2 on thread 4   'x' in task t1-2 on thread 4   
'    'y' in task t1-2 on thread 4   'z' in task t1-2 on thread 4   '{' in task t1-2 on thread 4   
'    '|' in task t1-2 on thread 4   '}' in task t1-2 on thread 4   '~' in task t1-2 on thread 4   
'    'q' in task t1-4 on thread 3   'r' in task t1-4 on thread 3   's' in task t1-4 on thread 3   
'    't' in task t1-4 on thread 3   'u' in task t1-4 on thread 3   'v' in task t1-4 on thread 3   
'    'w' in task t1-4 on thread 3   'x' in task t1-4 on thread 3   'y' in task t1-4 on thread 3   
'    'z' in task t1-4 on thread 3   '{' in task t1-4 on thread 3   '|' in task t1-4 on thread 3  

また、コードギャラリーでは、いくつかのサンプルタスクスケジューラを利用できます。.NET Framework 4 を使用した並列プログラミングのサンプルです。In addition, several sample task schedulers are available on Code Gallery: Samples for Parallel Programming with the .NET Framework 4.

注釈

TaskSchedulerクラスのインスタンスは、タスクスケジューラを表します。An instance of the TaskScheduler class represents a task scheduler. タスク スケジューラは、タスクの作業が最終的に実行されるようにします。A task scheduler ensures that the work of a task is eventually executed.

既定のタスク スケジューラは、負荷分散、スループット最大化のためのスレッドのインジェクション/リタイヤ、および全体のパフォーマンスの向上のためのワーク スティーリングを提供する .NET Framework 4 スレッド プールに基づいています。The default task scheduler is based on the .NET Framework 4 thread pool, which provides work-stealing for load-balancing, thread injection/retirement for maximum throughput, and overall good performance. ほとんどのシナリオでは、既定のタスク スケジューラで十分です。It should be sufficient for most scenarios.

クラスTaskSchedulerは、カスタマイズ可能なすべてのスケジューリングロジックの拡張ポイントとしても機能します。The TaskScheduler class also serves as the extension point for all customizable scheduling logic. これには、実行するタスクをスケジュールする方法や、スケジュールされたタスクをデバッガーに公開する方法などのメカニズムが含まれます。This includes mechanisms such as how to schedule a task for execution, and how scheduled tasks should be exposed to debuggers. 特別な機能が必要な場合は、カスタムスケジューラを作成し、特定のタスクまたはクエリに対して有効にすることができます。If you require special functionality, you can create a custom scheduler and enable it for specific tasks or queries.

このトピックの内容:In this topic:
既定のタスクスケジューラとスレッドプールThe default task scheduler and the thread pool
グローバルキューとローカルキューThe global queue vs. local queues
作業の盗難Work stealing
長時間実行されるタスクLong-running tasks
タスクのインライン展開Task inlining
同期コンテキストの指定Specifying a synchronization context

既定のタスクスケジューラとスレッドプールThe default task scheduler and the thread pool

タスク並列ライブラリと PLINQ の既定のスケジューラは、 ThreadPoolクラスによって表される .NET Framework スレッドプールを使用して、作業をキューに置いて実行します。The default scheduler for the Task Parallel Library and PLINQ uses the .NET Framework thread pool, which is represented by the ThreadPool class, to queue and execute work. スレッドプールは、 Task型によって提供される情報を使用して、並列タスクとクエリが表すことのできる粒度の細かい並列処理 (短時間の作業単位) を効率的にサポートします。The thread pool uses the information that is provided by the Task type to efficiently support the fine-grained parallelism (short-lived units of work) that parallel tasks and queries often represent.

グローバルキューとローカルキューThe global queue vs. local queues

スレッドプールは、各アプリケーションドメインのスレッドに対して、グローバル FIFO (先入れ先出し) 作業キューを保持します。The thread pool maintains a global FIFO (first-in, first-out) work queue for threads in each application domain. プログラムがThreadPool.QueueUserWorkItem (またはThreadPool.UnsafeQueueUserWorkItem) メソッドを呼び出すと、作業はこの共有キューに配置され、最終的には使用可能になる次のスレッドにキューから解除されます。Whenever a program calls the ThreadPool.QueueUserWorkItem (or ThreadPool.UnsafeQueueUserWorkItem) method, the work is put on this shared queue and eventually de-queued onto the next thread that becomes available. .NET Framework 4 以降では、このキューはConcurrentQueue<T>クラスに似たロックフリーのアルゴリズムを使用するように改善されています。Starting with the .NET Framework 4, this queue has been improved to use a lock-free algorithm that resembles the ConcurrentQueue<T> class. このロックフリーの実装を使用することにより、スレッドプールは作業項目をキューに置いたり、キューから除外したりする時間を短縮します。By using this lock-free implementation, the thread pool spends less time when it queues and de-queues work items. このパフォーマンス上の利点は、スレッドプールを使用するすべてのプログラムで利用できます。This performance benefit is available to all programs that use the thread pool.

トップレベル タスクは、別のタスクのコンテキストで作成されないタスクのことで、他の作業項目と同様にグローバル キューに配置されます。Top-level tasks, which are tasks that are not created in the context of another task, are put on the global queue just like any other work item. ただし、別のタスクのコンテキストで作成される入れ子のタスクまたは子タスクは、まったく異なる方法で処理されます。However, nested or child tasks, which are created in the context of another task, are handled quite differently. 子タスクまたは入れ子のタスクは、親タスクが実行されているスレッドに固有のローカル キューに配置されます。A child or nested task is put on a local queue that is specific to the thread on which the parent task is executing. 親タスクはトップレベルのタスクである場合もあれば、別のタスクの子である場合もあります。The parent task may be a top-level task or it also may be the child of another task. このスレッドは、追加の作業を処理する準備が整ったら、最初にローカル キューを検索します。When this thread is ready for more work, it first looks in the local queue. 作業項目がローカル キューで待機している場合は、それらにすばやくアクセスできます。If work items are waiting there, they can be accessed quickly. キャッシュの局所性を維持し、競合を減らすために、ローカルキューには後入れ先出し (LIFO) でアクセスします。The local queues are accessed in last-in, first-out order (LIFO) to preserve cache locality and reduce contention. 子タスクと入れ子になったタスクの詳細については、「アタッチおよびデタッチされた子タスク」を参照してください。For more information about child tasks and nested tasks, see Attached and Detached Child Tasks.

ローカルキューを使用すると、グローバルキューの負荷が軽減されるだけでなく、データの局所性も利用できます。The use of local queues not only reduces pressure on the global queue, but also takes advantage of data locality. ローカルキュー内の作業項目は、多くの場合、メモリ内に物理的に近いデータ構造を参照します。Work items in the local queue frequently reference data structures that are physically near one another in memory. このような場合は、最初のタスクが実行された後にデータがキャッシュに既に存在し、すぐにアクセスできるようになります。In these cases, the data is already in the cache after the first task has run and can be accessed quickly. 並列 LINQ (PLINQ)とクラスはParallel 、入れ子になったタスクと子タスクを広範囲に使用し、ローカルの作業キューを使用して重要な高速化を実現します。Both Parallel LINQ (PLINQ) and the Parallel class use nested tasks and child tasks extensively, and achieve significant speedups by using the local work queues.

作業の盗難Work stealing

.NET Framework 4 以降では、スレッドプールにもワークスティーリングアルゴリズムが用意されており、他のスレッドがキューで動作している間は、スレッドがアイドル状態にならないようにすることができます。Starting with the .NET Framework 4, the thread pool also features a work-stealing algorithm to help make sure that no threads are sitting idle while others still have work in their queues. スレッド プールのスレッドは、追加の作業を処理する準備が整ったら、最初にローカル キューの先頭を探します。次にグローバル キューを探し、最後に他のスレッドのローカル キューを探します。When a thread-pool thread is ready for more work, it first looks at the head of its local queue, then in the global queue, and then in the local queues of other threads. 別のスレッドのローカル キューで作業項目が見つかった場合、作業を効率的に実行できるように、最初にヒューリスティックを適用します。If it finds a work item in the local queue of another thread, it first applies heuristics to make sure that it can run the work efficiently. 可能な場合は、(FIFO の順序で) 末尾から作業項目のキューを解除します。If it can, it de-queues the work item from the tail (in FIFO order). これにより、各ローカル キューでの競合が減り、データの局所性が保持されます。This reduces contention on each local queue and preserves data locality. このアーキテクチャでは、スレッドプールの負荷分散を、過去のバージョンよりも効率的に行うことができます。This architecture helps the thread pool load-balance work more efficiently than past versions did.

長時間実行されるタスクLong-running tasks

タスクがローカル キューに配置されるのを明示的に防止したい場合があります。You may want to explicitly prevent a task from being put on a local queue. たとえば、特定の作業項目がかなり長い時間実行され、ローカル キューの他の作業項目をすべてブロックする可能性があることがわかっている場合などです。For example, you may know that a particular work item will run for a relatively long time and is likely to block all other work items on the local queue. このような場合は、System.Threading.Tasks.TaskCreationOptions オプションを指定できます。このオプションは、タスクの処理に追加のスレッドが必要になる可能性があるというヒントをスケジューラに提供し、他のスレッドまたはローカル キューの作業項目の進行をスケジューラがブロックするのを防ぎます。In this case, you can specify the System.Threading.Tasks.TaskCreationOptions option, which provides a hint to the scheduler that an additional thread might be required for the task so that it does not block the forward progress of other threads or work items on the local queue. このオプションを使用すると、グローバルキューとローカルキューを含め、スレッドプールを完全に回避できます。By using this option you avoid the thread pool completely, including the global and local queues.

タスクのインライン展開Task inlining

Taskが待機している場合、待機操作を実行しているスレッド上で同期的に実行されることがあります。In some cases when a Task is waited on, it may be executed synchronously on the thread that is performing the wait operation. これにより、追加のスレッドが不要になり、既存のスレッドを使用するのではなく、他のスレッドがブロックされてしまうため、パフォーマンスが向上します。This enhances performance by preventing the need for an additional thread and instead using the existing thread, which would have blocked otherwise. 再入によるエラーを回避するために、タスクのインライン展開は、関連するスレッドのローカルキューで待機対象が見つかった場合にのみ発生します。To prevent errors due to reentrancy, task inlining only occurs when the wait target is found in the relevant thread's local queue.

同期コンテキストの指定Specifying a synchronization context

TaskScheduler.FromCurrentSynchronizationContext メソッドを使用すると、タスクが特定のスレッドで実行されるようにスケジュールできます。You can use the TaskScheduler.FromCurrentSynchronizationContext method to specify that a task should be scheduled to run on a particular thread. これは、Windows フォームや Windows Presentation Foundation などのフレームワークで役立ちます。これらのフレームワークでは、多くの場合、ユーザー インターフェイス オブジェクトへのアクセスが、その UI オブジェクトが作成されたスレッドで実行されているコードに制限されるからです。This is useful in frameworks such as Windows Forms and Windows Presentation Foundation where access to user interface objects is often restricted to code that is running on the same thread on which the UI object was created.

次の例ではTaskScheduler.FromCurrentSynchronizationContext 、Windows Presentation Foundation (WPF) アプリでメソッドを使用して、ユーザーインターフェイス (UI) コントロールが作成されたのと同じスレッド上でタスクをスケジュールします。The following example uses the TaskScheduler.FromCurrentSynchronizationContext method in a Windows Presentation Foundation (WPF) app to schedule a task on the same thread that the user interface (UI) control was created on. この例では、指定されたディレクトリからランダムに選択されたイメージのモザイクを作成します。The example creates a mosaic of images that are randomly selected from a specified directory. WPF オブジェクトは、イメージの読み込みとサイズ変更に使用されます。The WPF objects are used to load and resize the images. その後、生のピクセルは、ループをFor使用して、ピクセルデータを大きな1バイト配列に書き込むタスクに渡されます。The raw pixels are then passed to a task that uses a For loop to write the pixel data into a large single-byte array. 2つのタイルで同じ配列要素が占有されていないため、同期は必要ありません。No synchronization is required because no two tiles occupy the same array elements. また、タイルは他のタイルとは別に計算されるため、任意の順序で書き込むこともできます。The tiles can also be written in any order because their position is calculated independently of any other tile. その後、大きな配列が UI スレッドで実行されるタスクに渡され、そこでピクセルデータがイメージコントロールに読み込まれます。The large array is then passed to a task that runs on the UI thread, where the pixel data is loaded into an Image control.

この例では、データを ui スレッドから移動し、並列ループとTaskオブジェクトを使用して変更してから、ui スレッドで実行されるタスクに渡します。The example moves data off the UI thread, modifies it by using parallel loops and Task objects, and then passes it back to a task that runs on the UI thread. この方法は、タスク並列ライブラリを使用して、WPF API でサポートされていない操作や、十分に高速ではない操作を実行する必要がある場合に便利です。This approach is useful when you have to use the Task Parallel Library to perform operations that either are not supported by the WPF API, or are not sufficiently fast. WPF でイメージのモザイクを作成するもう1つの方法System.Windows.Controls.WrapPanelは、コントロールを使用してイメージを追加することです。Another way to create an image mosaic in WPF is to use a System.Windows.Controls.WrapPanel control and add images to it. WrapPanel 、タイルを配置する作業を処理します。The WrapPanel handles the work of positioning the tiles. ただし、この作業は UI スレッドでのみ実行できます。However, this work can only be performed on the UI thread.

using System;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace WPF_CS1
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        private int fileCount;
        int colCount;
        int rowCount;
        private int tilePixelHeight;
        private int tilePixelWidth;
        private int largeImagePixelHeight;
        private int largeImagePixelWidth;
        private int largeImageStride;
        PixelFormat format;
        BitmapPalette palette = null;

        public MainWindow()
        {
            InitializeComponent();

            // For this example, values are hard-coded to a mosaic of 8x8 tiles.
            // Each tile is 50 pixels high and 66 pixels wide and 32 bits per pixel.
            colCount = 12;
            rowCount = 8;
            tilePixelHeight = 50;
            tilePixelWidth = 66;
            largeImagePixelHeight = tilePixelHeight * rowCount;
            largeImagePixelWidth = tilePixelWidth * colCount;
            largeImageStride = largeImagePixelWidth * (32 / 8);
            this.Width = largeImagePixelWidth + 40;
            image.Width = largeImagePixelWidth;
            image.Height = largeImagePixelHeight;


        }

        private void button_Click(object sender, RoutedEventArgs e)
        {

            // For best results use 1024 x 768 jpg files at 32bpp.
            string[] files = System.IO.Directory.GetFiles(@"C:\Users\Public\Pictures\Sample Pictures\", "*.jpg");

            fileCount = files.Length;
            Task<byte[]>[] images = new Task<byte[]>[fileCount];
            for (int i = 0; i < fileCount; i++)
            {
                int x = i;
                images[x] = Task.Factory.StartNew(() => LoadImage(files[x]));
            }

            // When they've all been loaded, tile them into a single byte array.
            var tiledImage = Task.Factory.ContinueWhenAll(
                images, (i) => TileImages(i));

            // We are currently on the UI thread. Save the sync context and pass it to
            // the next task so that it can access the UI control "image".
            var UISyncContext = TaskScheduler.FromCurrentSynchronizationContext();

            // On the UI thread, put the bytes into a bitmap and
            // display it in the Image control.
            var t3 = tiledImage.ContinueWith((antecedent) =>
            {
                // Get System DPI.
                Matrix m = PresentationSource.FromVisual(Application.Current.MainWindow)
                                            .CompositionTarget.TransformToDevice;
                double dpiX = m.M11;
                double dpiY = m.M22;

                BitmapSource bms = BitmapSource.Create(largeImagePixelWidth,
                    largeImagePixelHeight,
                    dpiX,
                    dpiY,
                    format,
                    palette, //use default palette
                    antecedent.Result,
                    largeImageStride);
                image.Source = bms;
            }, UISyncContext);
        }

        byte[] LoadImage(string filename)
        {
            // Use the WPF BitmapImage class to load and 
            // resize the bitmap. NOTE: Only 32bpp formats are supported correctly.
            // Support for additional color formats is left as an exercise
            // for the reader. For more information, see documentation for ColorConvertedBitmap.

            BitmapImage bitmapImage = new BitmapImage();
            bitmapImage.BeginInit();
            bitmapImage.UriSource = new Uri(filename);
            bitmapImage.DecodePixelHeight = tilePixelHeight;
            bitmapImage.DecodePixelWidth = tilePixelWidth;
            bitmapImage.EndInit();

            format = bitmapImage.Format;
            int size = (int)(bitmapImage.Height * bitmapImage.Width);
            int stride = (int)bitmapImage.Width * 4;
            byte[] dest = new byte[stride * tilePixelHeight];

            bitmapImage.CopyPixels(dest, stride, 0);

            return dest;
        }

        int Stride(int pixelWidth, int bitsPerPixel)
        {
            return (((pixelWidth * bitsPerPixel + 31) / 32) * 4);
        }

        // Map the individual image tiles to the large image
        // in parallel. Any kind of raw image manipulation can be
        // done here because we are not attempting to access any 
        // WPF controls from multiple threads.
        byte[] TileImages(Task<byte[]>[] sourceImages)
        {
            byte[] largeImage = new byte[largeImagePixelHeight * largeImageStride];
            int tileImageStride = tilePixelWidth * 4; // hard coded to 32bpp

            Random rand = new Random();
            Parallel.For(0, rowCount * colCount, (i) =>
            {
                // Pick one of the images at random for this tile.
                int cur = rand.Next(0, sourceImages.Length);
                byte[] pixels = sourceImages[cur].Result;

                // Get the starting index for this tile.
                int row = i / colCount;
                int col = (int)(i % colCount);
                int idx = ((row * (largeImageStride * tilePixelHeight)) + (col * tileImageStride));

                // Write the pixels for the current tile. The pixels are not contiguous
                // in the array, therefore we have to advance the index by the image stride
                // (minus the stride of the tile) for each scanline of the tile.
                int tileImageIndex = 0;
                for (int j = 0; j < tilePixelHeight; j++)
                {
                    // Write the next scanline for this tile.
                    for (int k = 0; k < tileImageStride; k++)
                    {
                        largeImage[idx++] = pixels[tileImageIndex++];
                    }
                    // Advance to the beginning of the next scanline.
                    idx += largeImageStride - tileImageStride;
                }
            });
            return largeImage;
        }
    }
}
Imports System.Threading.Tasks
Imports System.Windows
Imports System.Windows.Media
Imports System.Windows.Media.Imaging

Partial Public Class MainWindow : Inherits Window
    Dim fileCount As Integer
    Dim colCount As Integer
    Dim rowCount As Integer
    Dim tilePixelHeight As Integer
    Dim tilePixelWidth As Integer
    Dim largeImagePixelHeight As Integer
    Dim largeImagePixelWidth As Integer
    Dim largeImageStride As Integer
    Dim format As PixelFormat
    Dim palette As BitmapPalette = Nothing

    Public Sub New()
        InitializeComponent()

        ' For this example, values are hard-coded to a mosaic of 8x8 tiles.
        ' Each tile Is 50 pixels high and 66 pixels wide and 32 bits per pixel.
        colCount = 12
        rowCount = 8
        tilePixelHeight = 50
        tilePixelWidth = 66
        largeImagePixelHeight = tilePixelHeight * rowCount
        largeImagePixelWidth = tilePixelWidth * colCount
        largeImageStride = largeImagePixelWidth * (32 / 8)
        Me.Width = largeImagePixelWidth + 40
        image.Width = largeImagePixelWidth
        image.Height = largeImagePixelHeight
    End Sub

    Private Sub button_Click(sender As Object, e As RoutedEventArgs) _
        Handles button.Click

        ' For best results use 1024 x 768 jpg files at 32bpp.
        Dim files() As String = System.IO.Directory.GetFiles("C:\Users\Public\Pictures\Sample Pictures\", "*.jpg")

        fileCount = files.Length
        Dim images(fileCount - 1) As Task(Of Byte())
        For i As Integer = 0 To fileCount - 1
            Dim x As Integer = i
            images(x) = Task.Factory.StartNew(Function() LoadImage(files(x)))
        Next

        ' When they have all been loaded, tile them into a single byte array.
        'var tiledImage = Task.Factory.ContinueWhenAll(
        '        images, (i) >= TileImages(i));

        '        Dim tiledImage As Task(Of Byte()) = Task.Factory.ContinueWhenAll(images, Function(i As Task(Of Byte())) TileImages(i))
        Dim tiledImage = Task.Factory.ContinueWhenAll(images, Function(i As Task(Of Byte())()) TileImages(i))
        ' We are currently on the UI thread. Save the sync context and pass it to
        ' the next task so that it can access the UI control "image1".
        Dim UISyncContext = TaskScheduler.FromCurrentSynchronizationContext()

        ' On the UI thread, put the bytes into a bitmap and
        ' display it in the Image control.
        Dim t3 = tiledImage.ContinueWith(Sub(antecedent)
                                             ' Get System DPI.
                                             Dim m As Matrix = PresentationSource.FromVisual(Application.Current.MainWindow).CompositionTarget.TransformToDevice
                                             Dim dpiX As Double = m.M11
                                             Dim dpiY As Double = m.M22

                                             ' Use the default palette in creating the bitmap.
                                             Dim bms As BitmapSource = BitmapSource.Create(largeImagePixelWidth,
                                                                                           largeImagePixelHeight,
                                             dpiX,
                                             dpiY,
                                             format,
                                             palette,
                                             antecedent.Result,
                                             largeImageStride)
                                             image.Source = bms
                                         End Sub, UISyncContext)
    End Sub

    Public Function LoadImage(filename As String) As Byte()
        ' Use the WPF BitmapImage class to load and 
        ' resize the bitmap. NOTE: Only 32bpp formats are supported correctly.
        ' Support for additional color formats Is left as an exercise
        ' for the reader. For more information, see documentation for ColorConvertedBitmap.
        Dim bitmapImage As New BitmapImage()
        bitmapImage.BeginInit()
        bitmapImage.UriSource = New Uri(filename)
        bitmapImage.DecodePixelHeight = tilePixelHeight
        bitmapImage.DecodePixelWidth = tilePixelWidth
        bitmapImage.EndInit()

        format = bitmapImage.Format
        Dim size As Integer = CInt(bitmapImage.Height * bitmapImage.Width)
        Dim stride As Integer = CInt(bitmapImage.Width * 4)
        Dim dest(stride * tilePixelHeight - 1) As Byte

        bitmapImage.CopyPixels(dest, stride, 0)

        Return dest
    End Function

    Function Stride(pixelWidth As Integer, bitsPerPixel As Integer) As Integer
        Return (((pixelWidth * bitsPerPixel + 31) / 32) * 4)
    End Function

    ' Map the individual image tiles to the large image
    ' in parallel. Any kind of raw image manipulation can be
    ' done here because we are Not attempting to access any 
    ' WPF controls from multiple threads.
    Function TileImages(sourceImages As Task(Of Byte())()) As Byte()
        Dim largeImage(largeImagePixelHeight * largeImageStride - 1) As Byte
        Dim tileImageStride As Integer = tilePixelWidth * 4 ' hard coded To 32bpp

        Dim rand As New Random()
        Parallel.For(0, rowCount * colCount, Sub(i)
                                                 ' Pick one of the images at random for this tile.
                                                 Dim cur As Integer = rand.Next(0, sourceImages.Length)
                                                 Dim pixels() As Byte = sourceImages(cur).Result

                                                 ' Get the starting index for this tile.
                                                 Dim row As Integer = i \ colCount
                                                 Dim col As Integer = i Mod colCount
                                                 Dim idx As Integer = ((row * (largeImageStride * tilePixelHeight)) + (col * tileImageStride))

                                                 ' Write the pixels for the current tile. The pixels are Not contiguous
                                                 ' in the array, therefore we have to advance the index by the image stride
                                                 ' (minus the stride of the tile) for each scanline of the tile.
                                                 Dim tileImageIndex As Integer = 0
                                                 For j As Integer = 0 To tilePixelHeight - 1
                                                     ' Write the next scanline for this tile.
                                                     For k As Integer = 0 To tileImageStride - 1
                                                         largeImage(idx) = pixels(tileImageIndex)
                                                         idx += 1
                                                         tileImageIndex += 1
                                                     Next
                                                     ' Advance to the beginning of the next scanline.
                                                     idx += largeImageStride - tileImageStride
                                                 Next
                                             End Sub)
        Return largeImage
    End Function
End Class

この例を作成するには、Visual Studio で WPF アプリケーションプロジェクトを作成し、WPF_CS1 ( C# wpf プロジェクトの場合) または WPF_VB1 (Visual Basic wpf プロジェクトの場合) という名前を指定します。To create the example, create a WPF application project in Visual Studio and name it WPF_CS1 (for a C# WPF project) or WPF_VB1 (for a Visual Basic WPF project). その後、次の手順を実行します。Then do the following:

  1. デザインビューで、 Image ツールボックスからデザインサーフェイスの左上隅にコントロールをドラッグします。In design view, drag an Image control from the Toolbox onto the upper left corner of the design surface. [プロパティ] ウィンドウの [名前] ボックスに、コントロールに "image" という名前を指定します。In the Name textbox of the Properties window, name the control "image".

  2. コントロールをButton [ツールボックス] からアプリケーションウィンドウの左下の部分にドラッグします。Drag a Button control from the Toolbox to the lower left part of the application window. XAML ビューで、ボタンのContentプロパティを "モザイクの作成" として指定し、そのWidthプロパティを "100" として指定します。In XAML view, specify the Content property of the button as "Make a mosaic", and specify its Width property as "100". 要素にClickbutton_Click 追加Click="button_Click"して、この例のコードで定義されているイベントハンドラーでイベントを接続します。 <Button>Connect the Click event with the button_Click event handler defined in the example's code by adding Click="button_Click" to the <Button> element. [プロパティ] ウィンドウの [名前] ボックスに、コントロールに "button" という名前を指定します。In the Name textbox of the Properties window, name the control "button".

  3. MainWindow.xaml.cs または Mainwindow.xaml ファイルの内容全体を、この例のコードに置き換えます。Replace the entire contents of the MainWindow.xaml.cs or MainWindow.xaml.vb file with the code from this example. C# WPF プロジェクトの場合は、ワークスペースの名前がプロジェクト名と一致していることを確認します。For a C# WPF project, make sure that the name of the workspace matches the project name.

  4. この例では、C:\Users\Public\Pictures\Sample Pictures\という名前のディレクトリから JPEG イメージを読み取ります。The example reads JPEG images from a directory named C:\Users\Public\Pictures\Sample Pictures\. ディレクトリを作成し、その中にイメージを配置するか、またはイメージを含む他のディレクトリを参照するようにパスを変更します。Either create the directory and place some images in it, or change the path to refer to some other directory that contains images.

この例にはいくつかの制限があります。This example has some limitations. たとえば、32ビット/ピクセルのイメージのみがサポートされています。他の形式の画像は、サイズBitmapImage変更操作中にオブジェクトによって破損します。For example, only 32-bits-per-pixel images are supported; images in other formats are corrupted by the BitmapImage object during the resizing operation. また、ソースイメージはすべて、タイルのサイズよりも大きくする必要があります。Also, the source images must all be larger than the tile size. さらに演習として、複数のピクセル形式とファイルサイズを処理する機能を追加することもできます。As a further exercise, you can add functionality to handle multiple pixel formats and file sizes.

コンストラクター

TaskScheduler()

TaskScheduler を初期化します。Initializes the TaskScheduler.

プロパティ

Current

現在実行中のタスクに関連付けられている TaskScheduler を取得します。Gets the TaskScheduler associated with the currently executing task.

Default

.NET Framework によって提供される既定の TaskScheduler インスタンスを取得します。Gets the default TaskScheduler instance that is provided by the .NET Framework.

Id

この TaskScheduler の一意の ID を取得します。Gets the unique ID for this TaskScheduler.

MaximumConcurrencyLevel

この TaskScheduler がサポートできるコンカレンシー レベルの上限を示します。Indicates the maximum concurrency level this TaskScheduler is able to support.

メソッド

Equals(Object)

指定したオブジェクトが、現在のオブジェクトと等しいかどうかを判断します。Determines whether the specified object is equal to the current object.

(継承元 Object)
Finalize()

このスケジューラに関連付けられているすべてのリソースを解放します。Frees all resources associated with this scheduler.

FromCurrentSynchronizationContext()

現在の SynchronizationContext に関連付けられている TaskScheduler を作成します。Creates a TaskScheduler associated with the current SynchronizationContext.

GetHashCode()

既定のハッシュ関数として機能します。Serves as the default hash function.

(継承元 Object)
GetScheduledTasks()

デバッガー サポートの目的でのみ、現在実行待機中のスケジューラのキューに含まれている Task インスタンスの列挙可能なコレクションを生成します。For debugger support only, generates an enumerable of Task instances currently queued to the scheduler waiting to be executed.

GetType()

現在のインスタンスの Type を取得します。Gets the Type of the current instance.

(継承元 Object)
MemberwiseClone()

現在の Object の簡易コピーを作成します。Creates a shallow copy of the current Object.

(継承元 Object)
QueueTask(Task)

スケジューラのキューに Task を追加します。Queues a Task to the scheduler.

ToString()

現在のオブジェクトを表す文字列を返します。Returns a string that represents the current object.

(継承元 Object)
TryDequeue(Task)

このスケジューラのキューに以前含まれていた Task のデキューを試みます。Attempts to dequeue a Task that was previously queued to this scheduler.

TryExecuteTask(Task)

このスケジューラ上の指定された Task の実行を試みます。Attempts to execute the provided Task on this scheduler.

TryExecuteTaskInline(Task, Boolean)

指定された Task をこの呼び出しで同期的に実行できるかどうかを判断し、できる場合は実行します。Determines whether the provided Task can be executed synchronously in this call, and if it can, executes it.

イベント

UnobservedTaskException

エラーが発生したタスクの無視された例外が例外エスカレーション ポリシーをトリガーしようとする場合に発生します。既定では、プロセスを終了します。Occurs when a faulted task's unobserved exception is about to trigger exception escalation policy, which, by default, would terminate the process.

適用対象

スレッド セーフ

抽象TaskScheduler型のすべてのメンバーはスレッドセーフであり、複数のスレッドから同時に使用することができます。All members of the abstract TaskScheduler type are thread-safe and may be used from multiple threads concurrently.

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