mcs/class/System.Core/System.Linq.Parallel/ParallelExecuter.cs

   1 //
   2 // ParallelExecuter.cs
   3 //
   4 // Author:
   5 //       Jérémie "Garuma" Laval <jeremie.laval@gmail.com>
   6 //
   7 // Copyright (c) 2010 Jérémie "Garuma" Laval
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining a copy
  10 // of this software and associated documentation files (the "Software"), to deal
  11 // in the Software without restriction, including without limitation the rights
  12 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13 // copies of the Software, and to permit persons to whom the Software is
  14 // furnished to do so, subject to the following conditions:
  15 //
  16 // The above copyright notice and this permission notice shall be included in
  17 // all copies or substantial portions of the Software.
  18 //
  19 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  22 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  25 // THE SOFTWARE.
  26
  27 #if NET_4_0
  28 using System;
  29 using System.Threading;
  30 using System.Threading.Tasks;
  31 using System.Collections;
  32 using System.Collections.Generic;
  33 using System.Collections.Concurrent;
  34 using System.Linq.Parallel.QueryNodes;
  35
  36 namespace System.Linq.Parallel
  37 {
  38         internal static class ParallelExecuter
  39         {
  40                 internal static QueryOptions CheckQuery<T> (QueryBaseNode<T> startingNode)
  41                 {
  42                         return CheckQuery<T> (startingNode, false);
  43                 }
  44
  45                 internal static QueryOptions CheckQuery<T> (QueryBaseNode<T> startingNode, bool blocking)
  46                 {
  47                         return CheckQuery (startingNode, GetBestWorkerNumber (blocking));
  48                 }
  49
  50                 internal static QueryOptions CheckQuery<T> (QueryBaseNode<T> startingNode, int partitionCount)
  51                 {
  52                         QueryCheckerVisitor visitor = new QueryCheckerVisitor (partitionCount);
  53                         startingNode.Visit (visitor);
  54
  55                         return visitor.Options;
  56                 }
  57
  58                 internal static CancellationToken Chain (this CancellationToken self, CancellationTokenSource other)
  59                 {
  60                         CancellationTokenSource linked = CancellationTokenSource.CreateLinkedTokenSource (self, other.Token);
  61                         return linked.Token;
  62                 }
  63
  64                 internal static bool IsOrdered<TSource> (this QueryBaseNode<TSource> source)
  65                 {
  66                         QueryIsOrderedVisitor visitor = new QueryIsOrderedVisitor ();
  67                         source.Visit (visitor);
  68
  69                         return visitor.BehindOrderGuard;
  70                 }
  71
  72                 internal static int GetBestWorkerNumber ()
  73                 {
  74                         return GetBestWorkerNumber (false);
  75                 }
  76
  77                 internal static int GetBestWorkerNumber (bool blocking)
  78                 {
  79                         return blocking && Task.CurrentId == null ? Environment.ProcessorCount + 1 : Environment.ProcessorCount;
  80                 }
  81
  82                 internal static Task[] Process<TSource, TElement> (QueryBaseNode<TSource> node,
  83                                                                    Action<TElement, CancellationToken> call,
  84                                                                    Func<QueryBaseNode<TSource>, QueryOptions, IList<IEnumerable<TElement>>> acquisitionFunc,
  85                                                                    QueryOptions options)
  86                 {
  87                         return Process<TSource, TElement> (node, call, acquisitionFunc, null, options);
  88                 }
  89
  90                 internal static Task[] Process<TSource, TElement> (QueryBaseNode<TSource> node,
  91                                                                    Action<TElement, CancellationToken> call,
  92                                                                    Func<QueryBaseNode<TSource>, QueryOptions, IList<IEnumerable<TElement>>> acquisitionFunc,
  93                                                                    Action endAction,
  94                                                                    QueryOptions options)
  95                 {
  96                         CancellationTokenSource src
  97                                 = CancellationTokenSource.CreateLinkedTokenSource (options.ImplementerToken, options.Token);
  98
  99                         IList<IEnumerable<TElement>> enumerables = acquisitionFunc (node, options);
 100
 101                         Task[] tasks = new Task[enumerables.Count];
 102
 103                         for (int i = 0; i < tasks.Length; i++) {
 104                                 int index = i;
 105                                 tasks[i] = Task.Factory.StartNew (() => {
 106                                         try {
 107                                                 foreach (TElement item in enumerables[index]) {
 108                                                         if (!CheckTokens (options))
 109                                                                 break;
 110
 111                                                         try {
 112                                                                 call (item, src.Token);
 113                                                         } catch (OperationCanceledException canceledException) {
 114                                                                 if (canceledException.CancellationToken != src.Token)
 115                                                                         throw canceledException;
 116                                                         }
 117
 118                                                         if (!CheckTokens (options))
 119                                                                 break;
 120                                                 }
 121                                         } finally {
 122                                                 if (endAction != null)
 123                                                         endAction ();
 124                                         }
 125                                 }, options.Token, TaskCreationOptions.AttachedToParent | TaskCreationOptions.LongRunning, TaskScheduler.Default);
 126                         }
 127
 128                         return tasks;
 129                 }
 130
 131                 static bool CheckTokens (QueryOptions options)
 132                 {
 133                         // This is from specific operators
 134                         if (options.ImplementerToken.IsCancellationRequested)
 135                                 return false;
 136                         if (options.Token.IsCancellationRequested)
 137                                 throw new OperationCanceledException (options.Token);
 138                         return true;
 139                 }
 140
 141                 internal static void ProcessAndBlock<T> (QueryBaseNode<T> node, Action<T, CancellationToken> call)
 142                 {
 143                         QueryOptions options = CheckQuery (node, true);
 144
 145                         Task[] tasks = Process (node, call, new QueryBaseNodeHelper<T> ().GetEnumerables, options);
 146                         Task.WaitAll (tasks, options.Token);
 147                 }
 148
 149                 internal static Action ProcessAndCallback<T> (QueryBaseNode<T> node, Action<T, CancellationToken> call,
 150                                                               Action callback, QueryOptions options)
 151                 {
 152                         Task[] tasks = Process (node, call, new QueryBaseNodeHelper<T> ().GetEnumerables, options);
 153                         if (callback != null)
 154                                 Task.Factory.ContinueWhenAll (tasks,  (_) => callback ());
 155
 156                         return () => Task.WaitAll (tasks, options.Token);
 157                 }
 158
 159                 internal static Action ProcessAndCallback<T> (QueryBaseNode<T> node, Action<KeyValuePair<long, T>, CancellationToken> call,
 160                                                               Action endAction,
 161                                                               Action callback, QueryOptions options)
 162                 {
 163                         Task[] tasks = Process (node, call, new QueryBaseNodeHelper<T> ().GetOrderedEnumerables, endAction, options);
 164                         if (callback != null)
 165                                 Task.Factory.ContinueWhenAll (tasks,  (_) => callback ());
 166
 167                         return () => Task.WaitAll (tasks, options.Token);
 168                 }
 169
 170                 internal static void ProcessAndAggregate<T, U> (QueryBaseNode<T> node,
 171                                                                 Func<U> seedFunc,
 172                                                                 Func<U, T, U> localCall,
 173                                                                 Action<IList<U>> call)
 174                 {
 175                         QueryOptions options = CheckQuery (node, true);
 176
 177                         IList<IEnumerable<T>> enumerables = node.GetEnumerables (options);
 178                         U[] locals = new U[enumerables.Count];
 179                         Task[] tasks = new Task[enumerables.Count];
 180
 181                         if (seedFunc != null) {
 182                                 for (int i = 0; i < locals.Length; i++)
 183                                         locals[i] = seedFunc ();
 184                         }
 185
 186                         for (int i = 0; i < tasks.Length; i++) {
 187                                 var procSlot = new AggregateProcessSlot<T, U> (options,
 188                                                                                i,
 189                                                                                enumerables[i].GetEnumerator (),
 190                                                                                locals,
 191                                                                                localCall,
 192                                                                                seedFunc);
 193
 194                                 tasks[i] = Task.Factory.StartNew (procSlot.Process, options.Token);
 195                         }
 196
 197                         Task.WaitAll (tasks, options.Token);
 198
 199                         if (call != null)
 200                                 call (locals);
 201                 }
 202
 203                 class AggregateProcessSlot<T, U>
 204                 {
 205                         readonly QueryOptions options;
 206                         readonly int index;
 207                         readonly IEnumerator<T> enumerator;
 208                         readonly U[] locals;
 209                         readonly Func<U, T, U> localCall;
 210                         readonly Func<U> seedFunc;
 211
 212                         public AggregateProcessSlot (QueryOptions options,
 213                                                      int index,
 214                                                      IEnumerator<T> enumerator,
 215                                                      U[] locals,
 216                                                      Func<U, T, U> localCall,
 217                                                      Func<U> seedFunc)
 218                         {
 219                                 this.options = options;
 220                                 this.index = index;
 221                                 this.enumerator = enumerator;
 222                                 this.locals = locals;
 223                                 this.localCall = localCall;
 224                                 this.seedFunc = seedFunc;
 225                         }
 226
 227                         public void Process ()
 228                         {
 229                                 var token = options.Token;
 230                                 var implementerToken = options.ImplementerToken;
 231
 232                                 try {
 233                                         if (seedFunc == null) {
 234                                                 if (!enumerator.MoveNext ())
 235                                                         return;
 236                                                 locals[index] = (U)(object)enumerator.Current;
 237                                         }
 238
 239                                         while (enumerator.MoveNext ()) {
 240                                                 if (implementerToken.IsCancellationRequested)
 241                                                         break;
 242                                                 token.ThrowIfCancellationRequested ();
 243                                                 locals[index] = localCall (locals[index], enumerator.Current);
 244                                         }
 245                                 } finally {
 246                                         enumerator.Dispose ();
 247                                 }
 248                         }
 249                 }
 250
 251                 class QueryBaseNodeHelper<T>
 252                 {
 253                         internal IList<IEnumerable<T>> GetEnumerables (QueryBaseNode<T> source, QueryOptions options)
 254                         {
 255                                 return source.GetEnumerables (options);
 256                         }
 257
 258                         internal IList<IEnumerable<KeyValuePair<long,T>>> GetOrderedEnumerables (QueryBaseNode<T> source, QueryOptions options)
 259                         {
 260                                 return source.GetOrderedEnumerables (options);
 261                         }
 262                 }
 263         }
 264 }
 265 #endif