mcs/class/Mono.Parallel/Mono.Threading.Tasks/FixedTaskScheduler.cs

   1 // Scheduler.cs
   2 //
   3 // Copyright (c) 2008 Jérémie "Garuma" Laval
   4 //
   5 // Permission is hereby granted, free of charge, to any person obtaining a copy
   6 // of this software and associated documentation files (the "Software"), to deal
   7 // in the Software without restriction, including without limitation the rights
   8 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   9 // copies of the Software, and to permit persons to whom the Software is
  10 // furnished to do so, subject to the following conditions:
  11 //
  12 // The above copyright notice and this permission notice shall be included in
  13 // all copies or substantial portions of the Software.
  14 //
  15 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  18 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  21 // THE SOFTWARE.
  22 //
  23 //
  24
  25 #if NET_4_0 || MOBILE
  26 using System;
  27 using System.Threading;
  28 using System.Threading.Tasks;
  29 using System.Collections.Concurrent;
  30
  31 namespace Mono.Threading.Tasks
  32 {
  33         public class FixedTaskScheduler: TaskScheduler, IMonoTaskScheduler
  34         {
  35                 readonly IProducerConsumerCollection<Task> workQueue;
  36                 readonly ThreadWorker[]        workers;
  37                 readonly ManualResetEvent      pulseHandle = new ManualResetEvent (false);
  38
  39                 public FixedTaskScheduler ()
  40                         : this (Environment.ProcessorCount, ThreadPriority.Normal)
  41                 {
  42
  43                 }
  44
  45                 public FixedTaskScheduler (int maxWorker, ThreadPriority priority)
  46                 {
  47                         workQueue = new ConcurrentQueue<Task> ();
  48                         workers = new ThreadWorker [maxWorker];
  49
  50                         for (int i = 0; i < maxWorker; i++) {
  51                                 workers [i] = new ThreadWorker (workers, i, workQueue, new CyclicDeque<Task> (), priority, pulseHandle);
  52                                 workers [i].Pulse ();
  53                         }
  54                 }
  55
  56                 protected override void QueueTask (Task t)
  57                 {
  58                         // Add to the shared work pool
  59                         workQueue.TryAdd (t);
  60                         // Wake up some worker if they were asleep
  61                         PulseAll ();
  62                 }
  63
  64                 public void MonoParticipateUntil (Task task)
  65                 {
  66                         if (task.IsCompleted)
  67                                 return;
  68
  69                         ManualResetEventSlim evt = new ManualResetEventSlim (false);
  70                         task.ContinueWith (_ => evt.Set (), TaskContinuationOptions.ExecuteSynchronously);
  71                         if (evt.IsSet || task.IsCompleted)
  72                                 return;
  73
  74                         ParticipateUntilInternal (task, evt, -1);
  75                 }
  76
  77                 public bool MonoParticipateUntil (Task task, ManualResetEventSlim evt, int millisecondsTimeout)
  78                 {
  79                         if (task.IsCompleted)
  80                                 return false;
  81
  82                         bool isFromPredicate = true;
  83                         task.ContinueWith (_ => { isFromPredicate = false; evt.Set (); }, TaskContinuationOptions.ExecuteSynchronously);
  84
  85                         ParticipateUntilInternal (task, evt, millisecondsTimeout);
  86
  87                         if (task.IsCompleted)
  88                                 return false;
  89
  90                         return isFromPredicate;
  91                 }
  92
  93                 public void ParticipateUntilInternal (Task self, ManualResetEventSlim evt, int millisecondsTimeout)
  94                 {
  95                         ThreadWorker.ParticipativeWorkerMethod (self, evt, millisecondsTimeout, workQueue, workers, pulseHandle, (a, b) => true);
  96                 }
  97
  98                 static bool TaskCompletedPredicate (Task self)
  99                 {
 100                         return self.IsCompleted;
 101                 }
 102
 103                 public void PulseAll ()
 104                 {
 105                         pulseHandle.Set ();
 106                 }
 107
 108                 public void Dispose ()
 109                 {
 110                         foreach (ThreadWorker w in workers)
 111                                 w.Dispose ();
 112                 }
 113
 114                 #region Scheduler dummy stubs
 115                 protected override System.Collections.Generic.IEnumerable<Task> GetScheduledTasks ()
 116                 {
 117                         throw new System.NotImplementedException();
 118                 }
 119
 120                 protected override bool TryDequeue (Task task)
 121                 {
 122                         throw new System.NotImplementedException();
 123                 }
 124
 125                 protected override bool TryExecuteTaskInline (Task task, bool taskWasPreviouslyQueued)
 126                 {
 127                         task.Execute (null);
 128                         return true;
 129                 }
 130
 131                 public override int MaximumConcurrencyLevel {
 132                         get {
 133                                 return base.MaximumConcurrencyLevel;
 134                         }
 135                 }
 136                 #endregion
 137         }
 138 }
 139 #endif