Mercurial > pub > ImplabNet
annotate Implab/Parallels/AsyncQueue.cs @ 281:e0916ddc9950 v3 tip
code cleanup and refactoring
| author | cin |
|---|---|
| date | Fri, 01 Jun 2018 21:35:24 +0300 |
| parents | 8dd666e6b6bf |
| children |
| rev | line source |
|---|---|
| 119 | 1 using System.Threading; |
| 2 using System.Collections.Generic; | |
| 3 using System; | |
| 4 using System.Collections; | |
| 124 | 5 using System.Diagnostics; |
| 234 | 6 using System.Runtime.CompilerServices; |
| 119 | 7 |
| 8 namespace Implab.Parallels { | |
| 9 public class AsyncQueue<T> : IEnumerable<T> { | |
| 10 class Chunk { | |
| 233 | 11 public volatile Chunk next; |
| 119 | 12 |
| 233 | 13 volatile int m_low; |
| 14 volatile int m_hi; | |
| 15 volatile int m_alloc; | |
| 119 | 16 readonly int m_size; |
| 17 readonly T[] m_data; | |
| 18 | |
| 19 public Chunk(int size) { | |
| 20 m_size = size; | |
| 21 m_data = new T[size]; | |
| 22 } | |
| 23 | |
| 24 public Chunk(int size, T value) { | |
| 25 m_size = size; | |
| 26 m_hi = 1; | |
| 27 m_alloc = 1; | |
| 28 m_data = new T[size]; | |
| 29 m_data[0] = value; | |
| 30 } | |
| 31 | |
| 233 | 32 public Chunk(int size, int allocated) { |
| 121 | 33 m_size = size; |
| 233 | 34 m_hi = allocated; |
| 35 m_alloc = allocated; | |
| 121 | 36 m_data = new T[size]; |
| 233 | 37 } |
| 38 | |
| 39 public void WriteData(T[] data, int offset, int dest, int length) { | |
| 40 Array.Copy(data, offset, m_data, dest, length); | |
| 121 | 41 } |
| 42 | |
| 119 | 43 public int Low { |
| 44 get { return m_low; } | |
| 45 } | |
| 46 | |
| 47 public int Hi { | |
| 48 get { return m_hi; } | |
| 49 } | |
| 50 | |
| 127 | 51 public int Size { |
| 52 get { return m_size; } | |
| 53 } | |
| 54 | |
| 234 | 55 [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| 56 void AwaitWrites(int mark) { | |
| 57 if (m_hi != mark) { | |
| 58 SpinWait spin = new SpinWait(); | |
| 59 do { | |
| 60 spin.SpinOnce(); | |
| 61 } while (m_hi != mark); | |
| 62 } | |
| 63 } | |
| 64 | |
| 233 | 65 public bool TryEnqueue(T value) { |
| 66 int alloc; | |
| 67 do { | |
| 68 alloc = m_alloc; | |
| 69 if (alloc >= m_size) | |
| 70 return false; | |
| 71 } while(alloc != Interlocked.CompareExchange(ref m_alloc, alloc + 1, alloc)); | |
| 72 | |
| 119 | 73 m_data[alloc] = value; |
| 74 | |
| 234 | 75 AwaitWrites(alloc); |
| 233 | 76 m_hi = alloc + 1; |
| 77 | |
| 119 | 78 return true; |
| 79 } | |
| 80 | |
| 124 | 81 /// <summary> |
| 82 /// Prevents from allocating new space in the chunk and waits for all write operations to complete | |
| 83 /// </summary> | |
| 233 | 84 public void Seal() { |
| 85 var actual = Math.Min(Interlocked.Exchange(ref m_alloc, m_size), m_size); | |
| 234 | 86 AwaitWrites(actual); |
| 124 | 87 } |
| 88 | |
| 121 | 89 public bool TryDequeue(out T value, out bool recycle) { |
| 119 | 90 int low; |
| 91 do { | |
| 92 low = m_low; | |
| 93 if (low >= m_hi) { | |
| 94 value = default(T); | |
| 95 recycle = (low == m_size); | |
| 96 return false; | |
| 97 } | |
| 233 | 98 } while (low != Interlocked.CompareExchange(ref m_low, low + 1, low)); |
| 119 | 99 |
| 233 | 100 recycle = (low + 1 == m_size); |
| 119 | 101 value = m_data[low]; |
| 102 | |
| 103 return true; | |
| 104 } | |
| 105 | |
| 233 | 106 public bool TryEnqueueBatch(T[] batch, int offset, int length, out int enqueued) { |
| 107 int alloc; | |
| 108 do { | |
| 109 alloc = m_alloc; | |
| 110 if (alloc >= m_size) { | |
| 111 enqueued = 0; | |
| 112 return false; | |
| 113 } else { | |
| 114 enqueued = Math.Min(length, m_size - alloc); | |
| 115 } | |
| 116 } while (alloc != Interlocked.CompareExchange(ref m_alloc, alloc + enqueued, alloc)); | |
| 117 | |
| 118 Array.Copy(batch, offset, m_data, alloc, enqueued); | |
| 120 | 119 |
| 234 | 120 AwaitWrites(alloc); |
| 233 | 121 m_hi = alloc + enqueued; |
| 120 | 122 return true; |
| 123 } | |
| 124 | |
| 233 | 125 public bool TryDequeueBatch(T[] buffer, int offset, int length, out int dequeued, out bool recycle) { |
| 121 | 126 int low, hi, batchSize; |
| 127 | |
| 128 do { | |
| 129 low = m_low; | |
| 130 hi = m_hi; | |
| 131 if (low >= hi) { | |
| 132 dequeued = 0; | |
| 233 | 133 recycle = (low == m_size); |
| 121 | 134 return false; |
| 135 } | |
| 136 batchSize = Math.Min(hi - low, length); | |
| 233 | 137 } while (low != Interlocked.CompareExchange(ref m_low, low + batchSize, low)); |
| 121 | 138 |
| 139 dequeued = batchSize; | |
| 233 | 140 recycle = (low + batchSize == m_size); |
| 121 | 141 Array.Copy(m_data, low, buffer, offset, batchSize); |
| 142 | |
| 143 return true; | |
| 144 } | |
| 145 | |
| 119 | 146 public T GetAt(int pos) { |
| 147 return m_data[pos]; | |
| 148 } | |
| 149 } | |
| 150 | |
| 151 public const int DEFAULT_CHUNK_SIZE = 32; | |
| 233 | 152 public const int MAX_CHUNK_SIZE = 256; |
| 119 | 153 |
| 154 Chunk m_first; | |
| 155 Chunk m_last; | |
| 156 | |
| 233 | 157 public AsyncQueue() { |
| 158 m_first = m_last = new Chunk(DEFAULT_CHUNK_SIZE); | |
| 159 } | |
| 160 | |
| 121 | 161 /// <summary> |
| 162 /// Adds the specified value to the queue. | |
| 163 /// </summary> | |
| 164 /// <param name="value">Tha value which will be added to the queue.</param> | |
| 233 | 165 public void Enqueue(T value) { |
| 119 | 166 var last = m_last; |
| 233 | 167 SpinWait spin = new SpinWait(); |
| 168 while (!last.TryEnqueue(value)) { | |
| 119 | 169 // try to extend queue |
| 233 | 170 var chunk = new Chunk(DEFAULT_CHUNK_SIZE, value); |
| 171 var t = Interlocked.CompareExchange(ref m_last, chunk, last); | |
| 172 if (t == last) { | |
| 173 last.next = chunk; | |
| 174 break; | |
| 119 | 175 } else { |
| 233 | 176 last = t; |
| 119 | 177 } |
| 233 | 178 spin.SpinOnce(); |
| 119 | 179 } |
| 180 } | |
| 181 | |
| 121 | 182 /// <summary> |
| 183 /// Adds the specified data to the queue. | |
| 184 /// </summary> | |
| 185 /// <param name="data">The buffer which contains the data to be enqueued.</param> | |
| 186 /// <param name="offset">The offset of the data in the buffer.</param> | |
| 187 /// <param name="length">The size of the data to read from the buffer.</param> | |
| 233 | 188 public void EnqueueRange(T[] data, int offset, int length) { |
| 121 | 189 if (data == null) |
| 190 throw new ArgumentNullException("data"); | |
| 191 if (offset < 0) | |
| 192 throw new ArgumentOutOfRangeException("offset"); | |
| 193 if (length < 1 || offset + length > data.Length) | |
| 194 throw new ArgumentOutOfRangeException("length"); | |
| 195 | |
| 233 | 196 while (length > 0) { |
| 197 var last = m_last; | |
| 198 int enqueued; | |
| 121 | 199 |
| 233 | 200 if (last.TryEnqueueBatch(data, offset, length, out enqueued)) { |
| 121 | 201 length -= enqueued; |
| 202 offset += enqueued; | |
| 203 } | |
| 204 | |
| 233 | 205 if (length > 0) { |
| 206 // we have something to enqueue | |
| 121 | 207 |
| 233 | 208 var tail = length % MAX_CHUNK_SIZE; |
| 121 | 209 |
| 233 | 210 var chunk = new Chunk(Math.Max(tail, DEFAULT_CHUNK_SIZE), tail); |
| 211 | |
| 212 if (last != Interlocked.CompareExchange(ref m_last, chunk, last)) | |
| 213 continue; // we wasn't able to catch the writer, roundtrip | |
| 121 | 214 |
| 233 | 215 // we are lucky |
| 216 // we can exclusively write our batch, the other writers will continue their work | |
| 217 | |
| 218 length -= tail; | |
| 121 | 219 |
| 233 | 220 |
| 221 for(var i = 0; i < length; i+= MAX_CHUNK_SIZE) { | |
| 222 var node = new Chunk(MAX_CHUNK_SIZE, MAX_CHUNK_SIZE); | |
| 223 node.WriteData(data, offset, 0, MAX_CHUNK_SIZE); | |
| 224 offset += MAX_CHUNK_SIZE; | |
| 225 // fence last.next is volatile | |
| 226 last.next = node; | |
| 227 last = node; | |
| 121 | 228 } |
| 229 | |
| 233 | 230 if (tail > 0) |
| 231 chunk.WriteData(data, offset, 0, tail); | |
| 232 | |
| 233 // fence last.next is volatile | |
| 234 last.next = chunk; | |
| 235 return; | |
| 121 | 236 } |
| 237 } | |
| 238 } | |
| 239 | |
| 240 /// <summary> | |
| 241 /// Tries to retrieve the first element from the queue. | |
| 242 /// </summary> | |
| 243 /// <returns><c>true</c>, if element is dequeued, <c>false</c> otherwise.</returns> | |
| 244 /// <param name="value">The value of the dequeued element.</param> | |
| 119 | 245 public bool TryDequeue(out T value) { |
| 246 var chunk = m_first; | |
| 233 | 247 do { |
| 248 bool recycle; | |
| 119 | 249 |
| 250 var result = chunk.TryDequeue(out value, out recycle); | |
| 251 | |
| 233 | 252 if (recycle && chunk.next != null) { |
| 253 // this chunk is waste | |
| 254 chunk = Interlocked.CompareExchange(ref m_first, chunk.next, chunk); | |
| 255 } else { | |
| 119 | 256 return result; // this chunk is usable and returned actual result |
| 233 | 257 } |
| 119 | 258 |
| 259 if (result) // this chunk is waste but the true result is always actual | |
| 260 return true; | |
| 233 | 261 } while (true); |
| 119 | 262 } |
| 263 | |
| 121 | 264 /// <summary> |
| 265 /// Tries to dequeue the specified amount of data from the queue. | |
| 266 /// </summary> | |
| 267 /// <returns><c>true</c>, if data was deuqueued, <c>false</c> otherwise.</returns> | |
| 268 /// <param name="buffer">The buffer to which the data will be written.</param> | |
| 269 /// <param name="offset">The offset in the buffer at which the data will be written.</param> | |
| 270 /// <param name="length">The maximum amount of data to be retrieved.</param> | |
| 271 /// <param name="dequeued">The actual amout of the retrieved data.</param> | |
| 272 public bool TryDequeueRange(T[] buffer, int offset, int length, out int dequeued) { | |
| 273 if (buffer == null) | |
| 274 throw new ArgumentNullException("buffer"); | |
| 275 if (offset < 0) | |
| 276 throw new ArgumentOutOfRangeException("offset"); | |
| 277 if (length < 1 || offset + length > buffer.Length) | |
| 278 throw new ArgumentOutOfRangeException("length"); | |
| 279 | |
| 280 var chunk = m_first; | |
| 281 dequeued = 0; | |
| 233 | 282 do { |
| 283 bool recycle; | |
| 121 | 284 int actual; |
| 285 if (chunk.TryDequeueBatch(buffer, offset, length, out actual, out recycle)) { | |
| 286 offset += actual; | |
| 287 length -= actual; | |
| 288 dequeued += actual; | |
| 289 } | |
| 290 | |
| 233 | 291 if (recycle && chunk.next != null) { |
| 292 // this chunk is waste | |
| 293 chunk = Interlocked.CompareExchange(ref m_first, chunk.next, chunk); | |
| 294 } else { | |
| 295 chunk = null; | |
| 296 } | |
| 121 | 297 |
| 298 if (length == 0) | |
| 299 return true; | |
| 233 | 300 } while (chunk != null); |
| 121 | 301 |
| 302 return dequeued != 0; | |
| 303 } | |
| 304 | |
| 305 /// <summary> | |
| 306 /// Tries to dequeue all remaining data in the first chunk. | |
| 307 /// </summary> | |
| 308 /// <returns><c>true</c>, if data was dequeued, <c>false</c> otherwise.</returns> | |
|
122
0c8685c8b56b
minor fixes and improvements of AsyncQueue, additional tests
cin
parents:
121
diff
changeset
|
309 /// <param name="buffer">The buffer to which the data will be written.</param> |
| 121 | 310 /// <param name="offset">The offset in the buffer at which the data will be written.</param> |
| 311 /// <param name="length">Tha maximum amount of the data to be dequeued.</param> | |
| 312 /// <param name="dequeued">The actual amount of the dequeued data.</param> | |
| 313 public bool TryDequeueChunk(T[] buffer, int offset, int length, out int dequeued) { | |
| 314 if (buffer == null) | |
| 315 throw new ArgumentNullException("buffer"); | |
| 316 if (offset < 0) | |
| 317 throw new ArgumentOutOfRangeException("offset"); | |
| 318 if (length < 1 || offset + length > buffer.Length) | |
| 319 throw new ArgumentOutOfRangeException("length"); | |
| 320 | |
| 321 var chunk = m_first; | |
| 233 | 322 do { |
| 323 bool recycle; | |
| 324 chunk.TryDequeueBatch(buffer, offset, length, out dequeued, out recycle); | |
| 121 | 325 |
| 233 | 326 if (recycle && chunk.next != null) { |
| 327 // this chunk is waste | |
| 328 chunk = Interlocked.CompareExchange(ref m_first, chunk.next, chunk); | |
| 329 } else { | |
| 330 chunk = null; | |
| 121 | 331 } |
| 332 | |
| 333 // if we have dequeued any data, then return | |
| 334 if (dequeued != 0) | |
| 335 return true; | |
| 336 | |
| 233 | 337 } while (chunk != null); |
| 121 | 338 |
| 339 return false; | |
| 340 } | |
| 233 | 341 |
| 119 | 342 |
| 123 | 343 public void Clear() { |
| 344 // start the new queue | |
| 125 | 345 var chunk = new Chunk(DEFAULT_CHUNK_SIZE); |
| 124 | 346 do { |
| 347 var first = m_first; | |
| 233 | 348 if (first.next == null && first != m_last) { |
| 124 | 349 continue; |
| 233 | 350 } |
| 123 | 351 |
| 124 | 352 // here we will create inconsistency which will force others to spin |
| 353 // and prevent from fetching. chunk.next = null | |
| 354 if (first != Interlocked.CompareExchange(ref m_first, chunk, first)) | |
| 355 continue;// inconsistent | |
| 123 | 356 |
| 233 | 357 m_last = chunk; |
| 358 return; | |
| 359 } while (true); | |
| 360 } | |
| 361 | |
| 362 public List<T> Drain() { | |
| 234 | 363 Chunk chunk = null; |
| 233 | 364 do { |
| 365 var first = m_first; | |
| 366 // first.next is volatile | |
| 367 if (first.next == null) { | |
| 368 if (first != m_last) | |
| 369 continue; | |
| 370 else if (first.Hi == first.Low) | |
| 371 return new List<T>(); | |
| 372 } | |
| 373 | |
| 234 | 374 // start the new queue |
| 375 if (chunk == null) | |
| 376 chunk = new Chunk(DEFAULT_CHUNK_SIZE); | |
| 377 | |
| 233 | 378 // here we will create inconsistency which will force others to spin |
| 379 // and prevent from fetching. chunk.next = null | |
| 380 if (first != Interlocked.CompareExchange(ref m_first, chunk, first)) | |
| 381 continue;// inconsistent | |
| 382 | |
| 383 var last = Interlocked.Exchange(ref m_last, chunk); | |
| 124 | 384 |
| 385 return ReadChunks(first, last); | |
| 386 | |
| 233 | 387 } while (true); |
| 123 | 388 } |
| 233 | 389 |
| 390 static List<T> ReadChunks(Chunk chunk, object last) { | |
| 123 | 391 var result = new List<T>(); |
| 233 | 392 var buffer = new T[MAX_CHUNK_SIZE]; |
| 123 | 393 int actual; |
| 394 bool recycle; | |
| 233 | 395 SpinWait spin = new SpinWait(); |
| 123 | 396 while (chunk != null) { |
| 124 | 397 // ensure all write operations on the chunk are complete |
| 233 | 398 chunk.Seal(); |
| 124 | 399 |
| 123 | 400 // we need to read the chunk using this way |
| 401 // since some client still may completing the dequeue | |
| 402 // operation, such clients most likely won't get results | |
| 403 while (chunk.TryDequeueBatch(buffer, 0, buffer.Length, out actual, out recycle)) | |
| 404 result.AddRange(new ArraySegmentCollection(buffer, 0, actual)); | |
| 405 | |
| 124 | 406 if (chunk == last) { |
| 407 chunk = null; | |
| 408 } else { | |
| 409 while (chunk.next == null) | |
| 233 | 410 spin.SpinOnce(); |
| 124 | 411 chunk = chunk.next; |
| 412 } | |
| 123 | 413 } |
| 414 | |
| 233 | 415 return result; |
| 123 | 416 } |
| 417 | |
| 418 struct ArraySegmentCollection : ICollection<T> { | |
| 419 readonly T[] m_data; | |
| 420 readonly int m_offset; | |
| 421 readonly int m_length; | |
| 422 | |
| 423 public ArraySegmentCollection(T[] data, int offset, int length) { | |
| 424 m_data = data; | |
| 425 m_offset = offset; | |
| 426 m_length = length; | |
| 427 } | |
| 428 | |
| 429 #region ICollection implementation | |
| 430 | |
| 431 public void Add(T item) { | |
| 129 | 432 throw new NotSupportedException(); |
| 123 | 433 } |
| 434 | |
| 435 public void Clear() { | |
| 129 | 436 throw new NotSupportedException(); |
| 123 | 437 } |
| 438 | |
| 439 public bool Contains(T item) { | |
| 440 return false; | |
| 441 } | |
| 442 | |
| 443 public void CopyTo(T[] array, int arrayIndex) { | |
| 233 | 444 Array.Copy(m_data, m_offset, array, arrayIndex, m_length); |
| 123 | 445 } |
| 446 | |
| 447 public bool Remove(T item) { | |
| 129 | 448 throw new NotSupportedException(); |
| 123 | 449 } |
| 450 | |
| 451 public int Count { | |
| 452 get { | |
| 453 return m_length; | |
| 454 } | |
| 455 } | |
| 456 | |
| 457 public bool IsReadOnly { | |
| 458 get { | |
| 459 return true; | |
| 460 } | |
| 461 } | |
| 462 | |
| 463 #endregion | |
| 464 | |
| 465 #region IEnumerable implementation | |
| 466 | |
| 467 public IEnumerator<T> GetEnumerator() { | |
| 468 for (int i = m_offset; i < m_length + m_offset; i++) | |
| 469 yield return m_data[i]; | |
| 470 } | |
| 471 | |
| 472 #endregion | |
| 473 | |
| 474 #region IEnumerable implementation | |
| 475 | |
| 476 IEnumerator IEnumerable.GetEnumerator() { | |
| 477 return GetEnumerator(); | |
| 478 } | |
| 479 | |
| 480 #endregion | |
| 481 } | |
| 482 | |
| 119 | 483 #region IEnumerable implementation |
| 484 | |
| 485 class Enumerator : IEnumerator<T> { | |
| 486 Chunk m_current; | |
| 487 int m_pos = -1; | |
| 488 | |
| 489 public Enumerator(Chunk fisrt) { | |
| 490 m_current = fisrt; | |
| 491 } | |
| 492 | |
| 493 #region IEnumerator implementation | |
| 494 | |
| 495 public bool MoveNext() { | |
| 496 if (m_current == null) | |
| 497 return false; | |
| 498 | |
| 499 if (m_pos == -1) | |
| 500 m_pos = m_current.Low; | |
| 501 else | |
| 502 m_pos++; | |
| 127 | 503 |
| 119 | 504 if (m_pos == m_current.Hi) { |
| 127 | 505 |
| 506 m_current = m_pos == m_current.Size ? m_current.next : null; | |
| 507 | |
| 119 | 508 m_pos = 0; |
| 127 | 509 |
| 510 if (m_current == null) | |
| 511 return false; | |
| 119 | 512 } |
| 513 | |
| 514 return true; | |
| 515 } | |
| 516 | |
| 517 public void Reset() { | |
| 518 throw new NotSupportedException(); | |
| 519 } | |
| 520 | |
| 521 object IEnumerator.Current { | |
| 522 get { | |
| 523 return Current; | |
| 524 } | |
| 525 } | |
| 526 | |
| 527 #endregion | |
| 528 | |
| 529 #region IDisposable implementation | |
| 530 | |
| 531 public void Dispose() { | |
| 532 } | |
| 533 | |
| 534 #endregion | |
| 535 | |
| 536 #region IEnumerator implementation | |
| 537 | |
| 538 public T Current { | |
| 539 get { | |
| 540 if (m_pos == -1 || m_current == null) | |
| 541 throw new InvalidOperationException(); | |
| 542 return m_current.GetAt(m_pos); | |
| 543 } | |
| 544 } | |
| 545 | |
| 546 #endregion | |
| 547 } | |
| 548 | |
| 549 public IEnumerator<T> GetEnumerator() { | |
| 550 return new Enumerator(m_first); | |
| 551 } | |
| 552 | |
| 553 #endregion | |
| 554 | |
| 555 #region IEnumerable implementation | |
| 556 | |
| 557 IEnumerator IEnumerable.GetEnumerator() { | |
| 558 return GetEnumerator(); | |
| 559 } | |
| 560 | |
| 561 #endregion | |
| 562 } | |
| 563 } |