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Código para un grupo de subprocesos simple en C#

Question

Buscando algún código de muestra (C #) para una implementación simple del grupo de subprocesos.

Encontré uno en codeproject, pero el código era enorme y no necesito toda esa funcionalidad.

Esto es más para fines educativos de todos modos.

Answer 1

Esta es la implementación de grupo de subprocesos más simple e ingenua para fines educativos que podría encontrar (C # / .NET 3.5). No está utilizando la implementación del grupo de subprocesos de .NET de ninguna manera.

using System;
using System.Collections.Generic;
using System.Threading;
namespace SimpleThreadPool
{
public sealed class Pool : IDisposable
{
public Pool(int size)
{
this._workers = new LinkedList<Thread>();
for (var i = 0; i < size; ++i)
{
var worker = new Thread(this.Worker) { Name = string.Concat("Worker ", i) };
worker.Start();
this._workers.AddLast(worker);
}
}
public void Dispose()
{
var waitForThreads = false;
lock (this._tasks)
{
if (!this._disposed)
{
GC.SuppressFinalize(this);
this._disallowAdd = true; // wait for all tasks to finish processing while not allowing any more new tasks
while (this._tasks.Count > 0)
{
Monitor.Wait(this._tasks);
}
this._disposed = true;
Monitor.PulseAll(this._tasks); // wake all workers (none of them will be active at this point; disposed flag will cause then to finish so that we can join them)
waitForThreads = true;
}
}
if (waitForThreads)
{
foreach (var worker in this._workers)
{
worker.Join();
}
}
}
public void QueueTask(Action task)
{
lock (this._tasks)
{
if (this._disallowAdd) { throw new InvalidOperationException("This Pool instance is in the process of being disposed, can''t add anymore"); }
if (this._disposed) { throw new ObjectDisposedException("This Pool instance has already been disposed"); }
this._tasks.AddLast(task);
Monitor.PulseAll(this._tasks); // pulse because tasks count changed
}
}
private void Worker()
{
Action task = null;
while (true) // loop until threadpool is disposed
{
lock (this._tasks) // finding a task needs to be atomic
{
while (true) // wait for our turn in _workers queue and an available task
{
if (this._disposed)
{
return;
}
if (null != this._workers.First && object.ReferenceEquals(Thread.CurrentThread, this._workers.First.Value) && this._tasks.Count > 0) // we can only claim a task if its our turn (this worker thread is the first entry in _worker queue) and there is a task available
{
task = this._tasks.First.Value;
this._tasks.RemoveFirst();
this._workers.RemoveFirst();
Monitor.PulseAll(this._tasks); // pulse because current (First) worker changed (so that next available sleeping worker will pick up its task)
break; // we found a task to process, break out from the above ''while (true)'' loop
}
Monitor.Wait(this._tasks); // go to sleep, either not our turn or no task to process
}
}
task(); // process the found task
lock(this._tasks)
{
this._workers.AddLast(Thread.CurrentThread);
}
task = null;
}
}
private readonly LinkedList<Thread> _workers; // queue of worker threads ready to process actions
private readonly LinkedList<Action> _tasks = new LinkedList<Action>(); // actions to be processed by worker threads
private bool _disallowAdd; // set to true when disposing queue but there are still tasks pending
private bool _disposed; // set to true when disposing queue and no more tasks are pending
}
public static class Program
{
static void Main()
{
using (var pool = new Pool(5))
{
var random = new Random();
Action<int> randomizer = (index =>
{
Console.WriteLine("{0}: Working on index {1}", Thread.CurrentThread.Name, index);
Thread.Sleep(random.Next(20, 400));
Console.WriteLine("{0}: Ending {1}", Thread.CurrentThread.Name, index);
});
for (var i = 0; i < 40; ++i)
{
var i1 = i;
pool.QueueTask(() => randomizer(i1));
}
}
}
}
}

Answer 2

No es necesario implementar el suyo, ya que no es muy difícil utilizar la implementación de .NET existente.

Desde http://msdn.microsoft.com/en-us/library/3dasc8as(VS.80).aspx :

using System;
using System.Threading;
public class Fibonacci
{
public Fibonacci(int n, ManualResetEvent doneEvent)
{
_n = n;
_doneEvent = doneEvent;
}
// Wrapper method for use with thread pool.
public void ThreadPoolCallback(Object threadContext)
{
int threadIndex = (int)threadContext;
Console.WriteLine("thread {0} started...", threadIndex);
_fibOfN = Calculate(_n);
Console.WriteLine("thread {0} result calculated...", threadIndex);
_doneEvent.Set();
}
// Recursive method that calculates the Nth Fibonacci number.
public int Calculate(int n)
{
if (n <= 1)
{
return n;
}
return Calculate(n - 1) + Calculate(n - 2);
}
public int N { get { return _n; } }
private int _n;
public int FibOfN { get { return _fibOfN; } }
private int _fibOfN;
private ManualResetEvent _doneEvent;
}
public class ThreadPoolExample
{
static void Main()
{
const int FibonacciCalculations = 10;
// One event is used for each Fibonacci object
ManualResetEvent[] doneEvents = new ManualResetEvent[FibonacciCalculations];
Fibonacci[] fibArray = new Fibonacci[FibonacciCalculations];
Random r = new Random();
// Configure and launch threads using ThreadPool:
Console.WriteLine("launching {0} tasks...", FibonacciCalculations);
for (int i = 0; i < FibonacciCalculations; i++)
{
doneEvents[i] = new ManualResetEvent(false);
Fibonacci f = new Fibonacci(r.Next(20,40), doneEvents[i]);
fibArray[i] = f;
ThreadPool.QueueUserWorkItem(f.ThreadPoolCallback, i);
}
// Wait for all threads in pool to calculation...
WaitHandle.WaitAll(doneEvents);
Console.WriteLine("All calculations are complete.");
// Display the results...
for (int i= 0; i<FibonacciCalculations; i++)
{
Fibonacci f = fibArray[i];
Console.WriteLine("Fibonacci({0}) = {1}", f.N, f.FibOfN);
}
}
}