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fixed race condition in DispatchPool
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1 1 using System;
2 2 using Microsoft.VisualStudio.TestTools.UnitTesting;
3 3 using System.Reflection;
4 4 using System.Threading;
5 5 using Implab.Parallels;
6 6
7 7 namespace Implab.Test {
8 8 [TestClass]
9 9 public class AsyncTests {
10 10 [TestMethod]
11 11 public void ResolveTest() {
12 12 int res = -1;
13 13 var p = new Promise<int>();
14 14 p.Then(x => res = x);
15 15 p.Resolve(100);
16 16
17 17 Assert.AreEqual(100, res);
18 18 }
19 19
20 20 [TestMethod]
21 21 public void RejectTest() {
22 22 int res = -1;
23 23 Exception err = null;
24 24
25 25 var p = new Promise<int>();
26 26 p.Then(x => res = x, e => err = e);
27 27 p.Reject(new ApplicationException("error"));
28 28
29 29 Assert.AreEqual(res, -1);
30 30 Assert.AreEqual(err.Message, "error");
31 31
32 32 }
33 33
34 34 [TestMethod]
35 35 public void JoinSuccessTest() {
36 36 var p = new Promise<int>();
37 37 p.Resolve(100);
38 38 Assert.AreEqual(p.Join(), 100);
39 39 }
40 40
41 41 [TestMethod]
42 42 public void JoinFailTest() {
43 43 var p = new Promise<int>();
44 44 p.Reject(new ApplicationException("failed"));
45 45
46 46 try {
47 47 p.Join();
48 48 throw new ApplicationException("WRONG!");
49 49 } catch (TargetInvocationException err) {
50 50 Assert.AreEqual(err.InnerException.Message, "failed");
51 51 } catch {
52 52 Assert.Fail("Got wrong excaption");
53 53 }
54 54 }
55 55
56 56 [TestMethod]
57 57 public void MapTest() {
58 58 var p = new Promise<int>();
59 59
60 60 var p2 = p.Map(x => x.ToString());
61 61 p.Resolve(100);
62 62
63 63 Assert.AreEqual(p2.Join(), "100");
64 64 }
65 65
66 66 [TestMethod]
67 67 public void FixErrorTest() {
68 68 var p = new Promise<int>();
69 69
70 70 var p2 = p.Error(e => 101);
71 71
72 72 p.Reject(new Exception());
73 73
74 74 Assert.AreEqual(p2.Join(), 101);
75 75 }
76 76
77 77 [TestMethod]
78 78 public void ChainTest() {
79 79 var p1 = new Promise<int>();
80 80
81 81 var p3 = p1.Chain(x => {
82 82 var p2 = new Promise<string>();
83 83 p2.Resolve(x.ToString());
84 84 return p2;
85 85 });
86 86
87 87 p1.Resolve(100);
88 88
89 89 Assert.AreEqual(p3.Join(), "100");
90 90 }
91 91
92 92 [TestMethod]
93 93 public void PoolTest() {
94 94 var pid = Thread.CurrentThread.ManagedThreadId;
95 95 var p = AsyncPool.Invoke(() => Thread.CurrentThread.ManagedThreadId);
96 96
97 97 Assert.AreNotEqual(pid, p.Join());
98 98 }
99 99
100 100 [TestMethod]
101 101 public void WorkerPoolSizeTest() {
102 102 var pool = new WorkerPool(5, 10, 0);
103 103
104 104 Assert.AreEqual(5, pool.PoolSize);
105 105
106 106 pool.Invoke(() => { Thread.Sleep(100000000); return 10; });
107 107 pool.Invoke(() => { Thread.Sleep(100000000); return 10; });
108 108 pool.Invoke(() => { Thread.Sleep(100000000); return 10; });
109 109
110 110 Assert.AreEqual(5, pool.PoolSize);
111 111
112 112 for (int i = 0; i < 100; i++)
113 113 pool.Invoke(() => { Thread.Sleep(100000000); return 10; });
114 114 Thread.Sleep(200);
115 115 Assert.AreEqual(10, pool.PoolSize);
116 116
117 117 pool.Dispose();
118 118 }
119 119
120 120 [TestMethod]
121 121 public void WorkerPoolCorrectTest() {
122 122 var pool = new WorkerPool(0,1000,100);
123 123
124 124 int iterations = 1000;
125 125 int pending = iterations;
126 126 var stop = new ManualResetEvent(false);
127 127
128 128 var count = 0;
129 129 for (int i = 0; i < iterations; i++) {
130 130 pool
131 131 .Invoke(() => 1)
132 132 .Then(x => Interlocked.Add(ref count, x))
133 133 .Then(x => Math.Log10(x))
134 134 .Anyway(() => {
135 135 Interlocked.Decrement(ref pending);
136 136 if (pending == 0)
137 137 stop.Set();
138 138 });
139 139 }
140 140
141 141 stop.WaitOne();
142 142
143 143 Assert.AreEqual(iterations, count);
144 144 Console.WriteLine("Max threads: {0}", pool.MaxRunningThreads);
145 145 pool.Dispose();
146 146
147 147 }
148 148
149 149 [TestMethod]
150 150 public void WorkerPoolDisposeTest() {
151 151 var pool = new WorkerPool(5, 20);
152 152 Assert.AreEqual(5, pool.PoolSize);
153 153 pool.Dispose();
154 154 Thread.Sleep(500);
155 155 Assert.AreEqual(0, pool.PoolSize);
156 156 pool.Dispose();
157 157 }
158 158
159 159 [TestMethod]
160 160 public void MTQueueTest() {
161 161 var queue = new MTQueue<int>();
162 162 int res;
163 163
164 164 queue.Enqueue(10);
165 165 Assert.IsTrue(queue.TryDequeue(out res));
166 166 Assert.AreEqual(10, res);
167 167 Assert.IsFalse(queue.TryDequeue(out res));
168 168
169 169 for (int i = 0; i < 1000; i++)
170 170 queue.Enqueue(i);
171 171
172 172 for (int i = 0; i < 1000; i++) {
173 173 queue.TryDequeue(out res);
174 174 Assert.AreEqual(i, res);
175 175 }
176 176
177 177 int writers = 0;
178 178 int readers = 0;
179 179 var stop = new ManualResetEvent(false);
180 180 int total = 0;
181 181
182 182 int itemsPerWriter = 1000;
183 183 int writersCount = 3;
184 184
185 185 for (int i = 0; i < writersCount; i++) {
186 186 Interlocked.Increment(ref writers);
187 187 var wn = i;
188 188 AsyncPool
189 189 .InvokeNewThread(() => {
190 190 for (int ii = 0; ii < itemsPerWriter; ii++) {
191 191 queue.Enqueue(1);
192 192 }
193 193 return 1;
194 194 })
195 195 .Anyway(() => Interlocked.Decrement(ref writers));
196 196 }
197 197
198 198 for (int i = 0; i < 10; i++) {
199 199 Interlocked.Increment(ref readers);
200 200 var wn = i;
201 201 AsyncPool
202 202 .InvokeNewThread(() => {
203 203 int t;
204 204 do {
205 205 while (queue.TryDequeue(out t))
206 206 Interlocked.Add(ref total, t);
207 207 } while (writers > 0);
208 208 return 1;
209 209 })
210 210 .Anyway(() => {
211 211 Interlocked.Decrement(ref readers);
212 212 if (readers == 0)
213 213 stop.Set();
214 214 });
215 215 }
216 216
217 217 stop.WaitOne();
218 218
219 219 Assert.AreEqual(itemsPerWriter * writersCount, total);
220 220 }
221 221
222 222 [TestMethod]
223 223 public void ParallelMapTest() {
224 224
225 225 int count = 100000;
226 226
227 227 double[] args = new double[count];
228 228 var rand = new Random();
229 229
230 230 for (int i = 0; i < count; i++)
231 231 args[i] = rand.NextDouble();
232 232
233 233 var t = Environment.TickCount;
234 234 var res = args.ParallelMap(x => Math.Sin(x*x), 4).Join();
235 235
236 236 Console.WriteLine("Map complete in {0} ms", Environment.TickCount - t);
237 237
238 238 t = Environment.TickCount;
239 239 for (int i = 0; i < count; i++)
240 240 Assert.AreEqual(Math.Sin(args[i] * args[i]), res[i]);
241 241 Console.WriteLine("Verified in {0} ms", Environment.TickCount - t);
242 242 }
243 243
244 244 [TestMethod]
245 245 public void ChainedMapTest() {
246 246
247 using (var pool = new WorkerPool(0,100,0)) {
247 using (var pool = new WorkerPool(0,100,100)) {
248 248 int count = 10000;
249 249
250 250 double[] args = new double[count];
251 251 var rand = new Random();
252 252
253 253 for (int i = 0; i < count; i++)
254 254 args[i] = rand.NextDouble();
255 255
256 256 var t = Environment.TickCount;
257 257 var res = args
258 258 .ChainedMap(
259 259 x => pool.Invoke(
260 260 () => Math.Sin(x * x)
261 261 ),
262 262 4
263 263 )
264 264 .Join();
265 265
266 266 Console.WriteLine("Map complete in {0} ms", Environment.TickCount - t);
267 267
268 268 t = Environment.TickCount;
269 269 for (int i = 0; i < count; i++)
270 270 Assert.AreEqual(Math.Sin(args[i] * args[i]), res[i]);
271 271 Console.WriteLine("Verified in {0} ms", Environment.TickCount - t);
272 272 Console.WriteLine("Max workers: {0}", pool.MaxRunningThreads);
273 273 }
274 274 }
275 275
276 276 [TestMethod]
277 277 public void ParallelForEachTest() {
278 278
279 279 int count = 100000;
280 280
281 281 int[] args = new int[count];
282 282 var rand = new Random();
283 283
284 284 for (int i = 0; i < count; i++)
285 285 args[i] = (int)(rand.NextDouble() * 100);
286 286
287 287 int result = 0;
288 288
289 289 var t = Environment.TickCount;
290 290 args.ParallelForEach(x => Interlocked.Add(ref result, x), 4).Join();
291 291
292 292 Console.WriteLine("Iteration complete in {0} ms, result: {1}", Environment.TickCount - t, result);
293 293
294 294 int result2 = 0;
295 295
296 296 t = Environment.TickCount;
297 297 for (int i = 0; i < count; i++)
298 298 result2 += args[i];
299 299 Assert.AreEqual(result2, result);
300 300 Console.WriteLine("Verified in {0} ms", Environment.TickCount - t);
301 301 }
302 302
303 303 [TestMethod]
304 304 public void ComplexCase1Test() {
305 305 var flags = new bool[3];
306 306
307 307 // op1 (aync 200ms) => op2 (async 200ms) => op3 (sync map)
308 308
309 309 var p = PromiseHelper
310 310 .Sleep(200, "Alan")
311 311 .Cancelled(() => flags[0] = true)
312 312 .Chain(x =>
313 313 PromiseHelper
314 314 .Sleep(200, "Hi, " + x)
315 315 .Map(y => y)
316 316 .Cancelled(() => flags[1] = true)
317 317 )
318 318 .Cancelled(() => flags[2] = true);
319 319 Thread.Sleep(300);
320 320 p.Cancel();
321 321 try {
322 322 Assert.AreEqual(p.Join(), "Hi, Alan");
323 323 Assert.Fail("Shouldn't get here");
324 324 } catch (OperationCanceledException) {
325 325 }
326 326
327 327 Assert.IsFalse(flags[0]);
328 328 Assert.IsTrue(flags[1]);
329 329 Assert.IsTrue(flags[2]);
330 330 }
331 331
332 332 [TestMethod]
333 333 public void ChainedCancel1Test() {
334 334 // ΠΏΡ€ΠΈ ΠΎΡ‚ΠΌΠ΅Π½Π΅ сцСплСнной асинхронной ΠΎΠΏΠ΅Ρ€Π°Ρ†ΠΈΠΈ всС ΠΎΠ±Π΅Ρ‰Π°Π½ΠΈΠ΅ Π΄ΠΎΠ»ΠΆΠ½ΠΎ
335 335 // Π·Π°Π²Π΅Ρ€ΡˆΠ°Ρ‚ΡŒΡΡ ошибкой OperationCanceledException
336 336 var p = PromiseHelper
337 337 .Sleep(1, "Hi, HAL!")
338 338 .Chain(x => {
339 339 // запускаСм Π΄Π²Π΅ асинхронныС ΠΎΠΏΠ΅Ρ€Π°Ρ†ΠΈΠΈ
340 340 var result = PromiseHelper.Sleep(1000, "HEM ENABLED!!!");
341 341 // вторая опСрация отмСняСт ΠΏΠ΅Ρ€Π²ΡƒΡŽ Π΄ΠΎ Π·Π°Π²Π΅Ρ€ΡˆΠ΅Π½ΠΈΡ
342 342 PromiseHelper
343 343 .Sleep(100, "HAL, STOP!")
344 344 .Then(() => result.Cancel());
345 345 return result;
346 346 });
347 347 try {
348 348 p.Join();
349 349 } catch (TargetInvocationException err) {
350 350 Assert.IsTrue(err.InnerException is OperationCanceledException);
351 351 }
352 352 }
353 353
354 354 [TestMethod]
355 355 public void ChainedCancel2Test() {
356 356 // ΠΏΡ€ΠΈ ΠΎΡ‚ΠΌΠ΅Π½Π΅ Ρ†Π΅ΠΏΠΎΡ‡ΠΊΠΈ ΠΎΠ±Π΅Ρ‰Π°Π½ΠΈΠΉ, Π²Π»ΠΎΠΆΠ΅Π½Π½Ρ‹Π΅ ΠΎΠΏΠ΅Ρ€Π°Ρ†ΠΈΠΈ Ρ‚Π°ΠΊΠΆΠ΅ Π΄ΠΎΠ»ΠΆΠ½Ρ‹ ΠΎΡ‚ΠΌΠ΅Π½ΡΡ‚ΡŒΡΡ
357 357 IPromiseBase p = null;
358 358 var pSurvive = new Promise<bool>();
359 359 var hemStarted = new ManualResetEvent(false);
360 360 p = PromiseHelper
361 361 .Sleep(1, "Hi, HAL!")
362 362 .Chain(x => {
363 363 hemStarted.Set();
364 364 // запускаСм Π΄Π²Π΅ асинхронныС ΠΎΠΏΠ΅Ρ€Π°Ρ†ΠΈΠΈ
365 365 var result = PromiseHelper
366 366 .Sleep(1000, "HEM ENABLED!!!")
367 367 .Then(s => pSurvive.Resolve(false));
368 368
369 369 result
370 370 .Cancelled(() => pSurvive.Resolve(true));
371 371
372 372 return result;
373 373 });
374 374
375 375 hemStarted.WaitOne();
376 376 p.Cancel();
377 377
378 378 try {
379 379 p.Join();
380 380 } catch (OperationCanceledException) {
381 381 Assert.IsTrue(pSurvive.Join());
382 382 }
383 383 }
384 384 }
385 385 }
386 386
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@@ -1,335 +1,334
1 1 using System;
2 2 using System.Collections.Generic;
3 3 using System.Linq;
4 4 using System.Text;
5 5 using System.Threading;
6 6 using System.Diagnostics;
7 7
8 8 namespace Implab.Parallels {
9 9 public abstract class DispatchPool<TUnit> : IDisposable {
10 10 readonly int m_minThreads;
11 11 readonly int m_maxThreads;
12 12
13 13 int m_createdThreads = 0; // the current size of the pool
14 14 int m_activeThreads = 0; // the count of threads which are active
15 15 int m_sleepingThreads = 0; // the count of currently inactive threads
16 16 int m_maxRunningThreads = 0; // the meximum reached size of the pool
17 17 int m_exitRequired = 0; // the pool is going to shutdown, all unused workers are released
18 18 int m_releaseTimeout = 100; // the timeout while the working thread will wait for the new tasks before exit
19 19 int m_wakeEvents = 0; // the count of wake events
20 20
21 21 AutoResetEvent m_hasTasks = new AutoResetEvent(false);
22 22
23 23 protected DispatchPool(int min, int max) {
24 24 if (min < 0)
25 25 throw new ArgumentOutOfRangeException("min");
26 26 if (max <= 0)
27 27 throw new ArgumentOutOfRangeException("max");
28 28
29 29 if (min > max)
30 30 min = max;
31 31 m_minThreads = min;
32 32 m_maxThreads = max;
33 33 }
34 34
35 35 protected DispatchPool(int threads)
36 36 : this(threads, threads) {
37 37 }
38 38
39 39 protected DispatchPool() {
40 40 int maxThreads, maxCP;
41 41 ThreadPool.GetMaxThreads(out maxThreads, out maxCP);
42 42
43 43 m_minThreads = 0;
44 44 m_maxThreads = maxThreads;
45 45 }
46 46
47 47 protected void InitPool() {
48 48 for (int i = 0; i < m_minThreads; i++)
49 49 StartWorker();
50 50 }
51 51
52 52 public int PoolSize {
53 53 get {
54 54 return m_createdThreads;
55 55 }
56 56 }
57 57
58 58 public int ActiveThreads {
59 59 get {
60 60 return m_activeThreads;
61 61 }
62 62 }
63 63
64 64 public int MaxRunningThreads {
65 65 get {
66 66 return m_maxRunningThreads;
67 67 }
68 68 }
69 69
70 70 protected bool IsDisposed {
71 71 get {
72 72 return m_exitRequired != 0;
73 73 }
74 74 }
75 75
76 76 protected abstract bool TryDequeue(out TUnit unit);
77 77
78 78 #region thread execution traits
79 79 int SignalThread() {
80 80 var signals = Interlocked.Increment(ref m_wakeEvents);
81 81 if(signals == 1)
82 82 m_hasTasks.Set();
83 83 return signals;
84 84 }
85 85
86 86 bool FetchSignalOrWait(int timeout) {
87 87 var start = Environment.TickCount;
88 88
89 89 // ΠΎΠ·Π½Π°Ρ‡Π°Π΅Ρ‚, Ρ‡Ρ‚ΠΎ ΠΏΠΎΡ‚ΠΎΠΊ Π²Π»Π°Π΄Π΅Π΅Ρ‚ Π±Π»ΠΎΠΊΠΈΡ€ΠΎΠ²ΠΊΠΎΠΉ ΠΈ ΠΏΡ€ΠΈ ΡƒΡΠΏΠ΅ΡˆΠ½ΠΎΠΌ ΠΏΠΎΠ»ΡƒΡ‡Π΅Π½ΠΈΠΈ сигнала Π΄ΠΎΠ»ΠΆΠ΅Π½
90 90 // Π΅Π΅ Π²Π΅Ρ€Π½ΡƒΡ‚ΡŒ, Ρ‡Ρ‚ΠΎΠ±Ρ‹ Π΄Ρ€ΡƒΠ³ΠΎΠΉ ΠΎΠΆΠΈΠ΄Π°ΡŽΡ‰ΠΈΠΉ ΠΏΠΎΡ‚ΠΎΠΊ смог
91 91 bool hasLock = false;
92 92 do {
93 93 int signals;
94 94 do {
95 95 signals = m_wakeEvents;
96 96 if (signals == 0)
97 97 break;
98 98 } while (Interlocked.CompareExchange(ref m_wakeEvents, signals - 1, signals) != signals);
99 99
100 100 if (signals >= 1) {
101 101 if (signals > 1 && hasLock)
102 102 m_hasTasks.Set();
103 103 return true;
104 104 }
105 105
106 106 if (timeout != -1)
107 107 timeout = Math.Max(0, timeout - (Environment.TickCount - start));
108 108
109 109 // Ссли сигналов большС Π½Π΅ ΠΎΡΡ‚Π°Π»ΠΎΡΡŒ, Ρ‚ΠΎ ΠΏΠ΅Ρ€Π²Ρ‹ΠΉ ΠΏΠΎΡ‚ΠΎΠΊ, ΠΊΠΎΡ‚ΠΎΡ€Ρ‹ΠΉ дошСл сюда сбросит событиС
110 110 // ΠΈ ΡƒΠΉΠ΄Π΅Ρ‚ Π½Π° пустой Ρ†ΠΈΠΊΠ», послС Ρ‡Π΅Π³ΠΎ заблокируСтся
111 111
112 112 hasLock = true;
113 113 } while (m_hasTasks.WaitOne(timeout));
114 114
115 115 return false;
116 116 }
117 117
118 118 bool Sleep(int timeout) {
119 119 Interlocked.Increment(ref m_sleepingThreads);
120 120 if (FetchSignalOrWait(timeout)) {
121 121 Interlocked.Decrement(ref m_sleepingThreads);
122 122 return true;
123 123 } else {
124 124 Interlocked.Decrement(ref m_sleepingThreads);
125 125 return false;
126 126 }
127 127 }
128 128 #endregion
129 129
130 130 /// <summary>
131 131 /// ЗапускаСт Π»ΠΈΠ±ΠΎ Π½ΠΎΠ²Ρ‹ΠΉ ΠΏΠΎΡ‚ΠΎΠΊ, Ссли Ρ€Π°Π½ΡŒΡˆΠ΅ Π½Π΅ Π±Ρ‹Π»ΠΎ Π½ΠΈ ΠΎΠ΄Π½ΠΎΠ³ΠΎ ΠΏΠΎΡ‚ΠΎΠΊΠ°, Π»ΠΈΠ±ΠΎ устанавливаСт событиС ΠΏΡ€ΠΎΠ±ΡƒΠΆΠ΄Π΅Π½ΠΈΠ΅ ΠΎΠ΄Π½ΠΎΠ³ΠΎ спящСго ΠΏΠΎΡ‚ΠΎΠΊΠ°
132 132 /// </summary>
133 133 protected void GrowPool() {
134 134 if (m_exitRequired != 0)
135 135 return;
136 136 if (m_sleepingThreads > m_wakeEvents) {
137 137 //Console.WriteLine("Waking threads (sleeps {0}, pending {1})", m_sleepingThreads, m_wakeEvents);
138 138
139 139 // all sleeping threads may gone
140 140 SignalThread(); // wake a sleeping thread;
141 141
142 142 // we can't check whether signal has been processed
143 143 // anyway it may take some time for the thread to start
144 144 // we will ensure that at least one thread is running
145 145
146 146 EnsurePoolIsAlive();
147 147 } else {
148 148 // if there is no sleeping threads in the pool
149 149 if (!StartWorker()) {
150 150 // we haven't started a new thread, but the current can be on the way to terminate and it can't process the queue
151 151 // send it a signal to spin again
152 152 SignalThread();
153 153 EnsurePoolIsAlive();
154 154 }
155 155 }
156 156 }
157 157
158 private void EnsurePoolIsAlive() {
158 protected void EnsurePoolIsAlive() {
159 159 if (AllocateThreadSlot(1)) {
160 160 // if there were no threads in the pool
161 161 var worker = new Thread(this.Worker);
162 162 worker.IsBackground = true;
163 163 worker.Start();
164 164 }
165 165 }
166 166
167 private bool Suspend() {
167 protected virtual bool Suspend() {
168 168 //no tasks left, exit if the thread is no longer needed
169 169 bool last;
170 170 bool requestExit;
171 171
172 172 // if threads have a timeout before releasing
173 173 if (m_releaseTimeout > 0)
174 174 requestExit = !Sleep(m_releaseTimeout);
175 175 else
176 176 requestExit = true;
177 177
178 178 if (!requestExit)
179 179 return true;
180 180
181 181 // release unsused thread
182 182 if (requestExit && ReleaseThreadSlot(out last)) {
183 183 // in case at the moment the last thread was being released
184 184 // a new task was added to the queue, we need to try
185 185 // to revoke the thread to avoid the situation when the task is left unprocessed
186 186 if (last && FetchSignalOrWait(0)) { // FetchSignalOrWait(0) will fetch pending task or will return false
187 187 SignalThread(); // since FetchSignalOrWait(0) has fetched the signal we need to reschedule it
188 188 return AllocateThreadSlot(1); // ensure that at least one thread is alive
189 189 }
190 190
191 191 return false;
192 192 }
193 193
194 194 // wait till infinity
195 195 Sleep(-1);
196 196
197 197 return true;
198 198 }
199 199
200 200 #region thread slots traits
201 201
202 202 bool AllocateThreadSlot() {
203 203 int current;
204 204 // use spins to allocate slot for the new thread
205 205 do {
206 206 current = m_createdThreads;
207 207 if (current >= m_maxThreads || m_exitRequired != 0)
208 208 // no more slots left or the pool has been disposed
209 209 return false;
210 210 } while (current != Interlocked.CompareExchange(ref m_createdThreads, current + 1, current));
211 211
212 212 UpdateMaxThreads(current + 1);
213 213
214 214 return true;
215 215 }
216 216
217 217 bool AllocateThreadSlot(int desired) {
218 218 if (desired - 1 != Interlocked.CompareExchange(ref m_createdThreads, desired, desired - 1))
219 219 return false;
220 220
221 221 UpdateMaxThreads(desired);
222 222
223 223 return true;
224 224 }
225 225
226 226 bool ReleaseThreadSlot(out bool last) {
227 227 last = false;
228 228 int current;
229 229 // use spins to release slot for the new thread
230 230 do {
231 231 current = m_createdThreads;
232 232 if (current <= m_minThreads && m_exitRequired == 0)
233 233 // the thread is reserved
234 234 return false;
235 235 } while (current != Interlocked.CompareExchange(ref m_createdThreads, current - 1, current));
236 236
237 237 last = (current == 1);
238 238
239 239 return true;
240 240 }
241 241
242 242 /// <summary>
243 243 /// releases thread slot unconditionally, used during cleanup
244 244 /// </summary>
245 245 /// <returns>true - no more threads left</returns>
246 246 bool ReleaseThreadSlotAnyway() {
247 247 var left = Interlocked.Decrement(ref m_createdThreads);
248 248 return left == 0;
249 249 }
250 250
251 251 void UpdateMaxThreads(int count) {
252 252 int max;
253 253 do {
254 254 max = m_maxRunningThreads;
255 255 if (max >= count)
256 256 break;
257 257 } while(max != Interlocked.CompareExchange(ref m_maxRunningThreads, count, max));
258 258 }
259 259
260 260 #endregion
261 261
262 262 bool StartWorker() {
263 263 if (AllocateThreadSlot()) {
264 264 // slot successfully allocated
265 265 var worker = new Thread(this.Worker);
266 266 worker.IsBackground = true;
267 267 worker.Start();
268 268
269 269 return true;
270 270 } else {
271 271 return false;
272 272 }
273 273 }
274 274
275 275 protected abstract void InvokeUnit(TUnit unit);
276 276
277 277 void Worker() {
278 278 TUnit unit;
279 279 //Console.WriteLine("{0}: Active", Thread.CurrentThread.ManagedThreadId);
280 280 Interlocked.Increment(ref m_activeThreads);
281 281 do {
282 282 // exit if requested
283 283 if (m_exitRequired != 0) {
284 284 // release the thread slot
285 285 Interlocked.Decrement(ref m_activeThreads);
286 286 if (ReleaseThreadSlotAnyway()) // it was the last worker
287 287 m_hasTasks.Dispose();
288 288 else
289 289 SignalThread(); // wake next worker
290 290 break;
291 291 }
292 292
293 293 // fetch task
294 294 if (TryDequeue(out unit)) {
295 295 InvokeUnit(unit);
296 296 continue;
297 297 }
298
299 298 Interlocked.Decrement(ref m_activeThreads);
300 299
301 300 // entering suspend state
302 301 // keep this thread and wait
303 302 if (!Suspend())
304 303 break;
305 304 //Console.WriteLine("{0}: Awake", Thread.CurrentThread.ManagedThreadId);
306 305 Interlocked.Increment(ref m_activeThreads);
307 306 } while (true);
308 307 //Console.WriteLine("{0}: Exited", Thread.CurrentThread.ManagedThreadId);
309 308 }
310 309
311 310 protected virtual void Dispose(bool disposing) {
312 311 if (disposing) {
313 312 if (m_exitRequired == 0) {
314 313 if (Interlocked.CompareExchange(ref m_exitRequired, 1, 0) != 0)
315 314 return;
316 315
317 316 // wake sleeping threads
318 317 if (m_createdThreads > 0)
319 318 SignalThread();
320 319 else
321 320 m_hasTasks.Dispose();
322 321 GC.SuppressFinalize(this);
323 322 }
324 323 }
325 324 }
326 325
327 326 public void Dispose() {
328 327 Dispose(true);
329 328 }
330 329
331 330 ~DispatchPool() {
332 331 Dispose(false);
333 332 }
334 333 }
335 334 }
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@@ -1,77 +1,93
1 1 using System;
2 2 using System.Collections.Generic;
3 3 using System.Linq;
4 4 using System.Text;
5 5 using System.Threading;
6 6 using System.Diagnostics;
7 7
8 8 namespace Implab.Parallels {
9 9 public class WorkerPool : DispatchPool<Action> {
10 10
11 11 MTQueue<Action> m_queue = new MTQueue<Action>();
12 12 int m_queueLength = 0;
13 13 readonly int m_threshold = 1;
14 14
15 15 public WorkerPool(int minThreads, int maxThreads, int threshold)
16 16 : base(minThreads, maxThreads) {
17 17 m_threshold = threshold;
18 18 InitPool();
19 19 }
20 20
21 21 public WorkerPool(int minThreads, int maxThreads) :
22 22 base(minThreads, maxThreads) {
23 23 InitPool();
24 24 }
25 25
26 26 public WorkerPool(int threads)
27 27 : base(threads) {
28 28 InitPool();
29 29 }
30 30
31 31 public WorkerPool()
32 32 : base() {
33 33 InitPool();
34 34 }
35 35
36 36 public Promise<T> Invoke<T>(Func<T> task) {
37 37 if (task == null)
38 38 throw new ArgumentNullException("task");
39 39 if (IsDisposed)
40 40 throw new ObjectDisposedException(ToString());
41 41
42 42 var promise = new Promise<T>();
43 43
44 44 EnqueueTask(delegate() {
45 45 try {
46 46 promise.Resolve(task());
47 47 } catch (Exception e) {
48 48 promise.Reject(e);
49 49 }
50 50 });
51 51
52 52 return promise;
53 53 }
54 54
55 55 protected void EnqueueTask(Action unit) {
56 56 Debug.Assert(unit != null);
57 57 var len = Interlocked.Increment(ref m_queueLength);
58 58 m_queue.Enqueue(unit);
59 59
60 60 if (len > m_threshold*ActiveThreads)
61 61 GrowPool();
62 62 }
63 63
64 64 protected override bool TryDequeue(out Action unit) {
65 65 if (m_queue.TryDequeue(out unit)) {
66 66 Interlocked.Decrement(ref m_queueLength);
67 67 return true;
68 68 }
69 69 return false;
70 70 }
71 71
72 protected override bool Suspend() {
73 // This override solves race condition
74 // WORKER CLIENT
75 // ---------------------------------------
76 // TryDeque == false
77 // Enqueue(unit), queueLen++
78 // GrowPool? == NO
79 // ActiveThreads--
80 // Suspend
81 // queueLength > 0
82 // continue
83 if (m_queueLength > 0)
84 return true;
85 return base.Suspend();
86 }
87
72 88 protected override void InvokeUnit(Action unit) {
73 89 unit();
74 90 }
75 91
76 92 }
77 93 }
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