Mercurial > hg > graal-compiler
annotate src/share/vm/utilities/taskqueue.hpp @ 360:5d254928c888
Merge
author | ysr |
---|---|
date | Wed, 27 Aug 2008 11:20:46 -0700 |
parents | 1ee8caae33af |
children | 81cd571500b0 |
rev | line source |
---|---|
0 | 1 /* |
196 | 2 * Copyright 2001-2008 Sun Microsystems, Inc. All Rights Reserved. |
0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 class TaskQueueSuper: public CHeapObj { | |
26 protected: | |
27 // The first free element after the last one pushed (mod _n). | |
28 // (For now we'll assume only 32-bit CAS). | |
29 volatile juint _bottom; | |
30 | |
31 // log2 of the size of the queue. | |
32 enum SomeProtectedConstants { | |
33 Log_n = 14 | |
34 }; | |
35 | |
36 // Size of the queue. | |
37 juint n() { return (1 << Log_n); } | |
38 // For computing "x mod n" efficiently. | |
39 juint n_mod_mask() { return n() - 1; } | |
40 | |
41 struct Age { | |
42 jushort _top; | |
43 jushort _tag; | |
44 | |
45 jushort tag() const { return _tag; } | |
46 jushort top() const { return _top; } | |
47 | |
48 Age() { _tag = 0; _top = 0; } | |
49 | |
50 friend bool operator ==(const Age& a1, const Age& a2) { | |
51 return a1.tag() == a2.tag() && a1.top() == a2.top(); | |
52 } | |
53 | |
54 }; | |
55 Age _age; | |
56 // These make sure we do single atomic reads and writes. | |
57 Age get_age() { | |
58 jint res = *(volatile jint*)(&_age); | |
59 return *(Age*)(&res); | |
60 } | |
61 void set_age(Age a) { | |
62 *(volatile jint*)(&_age) = *(int*)(&a); | |
63 } | |
64 | |
65 jushort get_top() { | |
66 return get_age().top(); | |
67 } | |
68 | |
69 // These both operate mod _n. | |
70 juint increment_index(juint ind) { | |
71 return (ind + 1) & n_mod_mask(); | |
72 } | |
73 juint decrement_index(juint ind) { | |
74 return (ind - 1) & n_mod_mask(); | |
75 } | |
76 | |
77 // Returns a number in the range [0.._n). If the result is "n-1", it | |
78 // should be interpreted as 0. | |
79 juint dirty_size(juint bot, juint top) { | |
80 return ((jint)bot - (jint)top) & n_mod_mask(); | |
81 } | |
82 | |
83 // Returns the size corresponding to the given "bot" and "top". | |
84 juint size(juint bot, juint top) { | |
85 juint sz = dirty_size(bot, top); | |
86 // Has the queue "wrapped", so that bottom is less than top? | |
87 // There's a complicated special case here. A pair of threads could | |
88 // perform pop_local and pop_global operations concurrently, starting | |
89 // from a state in which _bottom == _top+1. The pop_local could | |
90 // succeed in decrementing _bottom, and the pop_global in incrementing | |
91 // _top (in which case the pop_global will be awarded the contested | |
92 // queue element.) The resulting state must be interpreted as an empty | |
93 // queue. (We only need to worry about one such event: only the queue | |
94 // owner performs pop_local's, and several concurrent threads | |
95 // attempting to perform the pop_global will all perform the same CAS, | |
96 // and only one can succeed. Any stealing thread that reads after | |
97 // either the increment or decrement will seen an empty queue, and will | |
98 // not join the competitors. The "sz == -1 || sz == _n-1" state will | |
99 // not be modified by concurrent queues, so the owner thread can reset | |
100 // the state to _bottom == top so subsequent pushes will be performed | |
101 // normally. | |
102 if (sz == (n()-1)) return 0; | |
103 else return sz; | |
104 } | |
105 | |
106 public: | |
107 TaskQueueSuper() : _bottom(0), _age() {} | |
108 | |
109 // Return "true" if the TaskQueue contains any tasks. | |
110 bool peek(); | |
111 | |
112 // Return an estimate of the number of elements in the queue. | |
113 // The "careful" version admits the possibility of pop_local/pop_global | |
114 // races. | |
115 juint size() { | |
116 return size(_bottom, get_top()); | |
117 } | |
118 | |
119 juint dirty_size() { | |
120 return dirty_size(_bottom, get_top()); | |
121 } | |
122 | |
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
123 void set_empty() { |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
124 _bottom = 0; |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
125 _age = Age(); |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
126 } |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
127 |
0 | 128 // Maximum number of elements allowed in the queue. This is two less |
129 // than the actual queue size, for somewhat complicated reasons. | |
130 juint max_elems() { return n() - 2; } | |
131 | |
132 }; | |
133 | |
134 template<class E> class GenericTaskQueue: public TaskQueueSuper { | |
135 private: | |
136 // Slow paths for push, pop_local. (pop_global has no fast path.) | |
137 bool push_slow(E t, juint dirty_n_elems); | |
138 bool pop_local_slow(juint localBot, Age oldAge); | |
139 | |
140 public: | |
141 // Initializes the queue to empty. | |
142 GenericTaskQueue(); | |
143 | |
144 void initialize(); | |
145 | |
146 // Push the task "t" on the queue. Returns "false" iff the queue is | |
147 // full. | |
148 inline bool push(E t); | |
149 | |
150 // If succeeds in claiming a task (from the 'local' end, that is, the | |
151 // most recently pushed task), returns "true" and sets "t" to that task. | |
152 // Otherwise, the queue is empty and returns false. | |
153 inline bool pop_local(E& t); | |
154 | |
155 // If succeeds in claiming a task (from the 'global' end, that is, the | |
156 // least recently pushed task), returns "true" and sets "t" to that task. | |
157 // Otherwise, the queue is empty and returns false. | |
158 bool pop_global(E& t); | |
159 | |
160 // Delete any resource associated with the queue. | |
161 ~GenericTaskQueue(); | |
162 | |
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
163 // apply the closure to all elements in the task queue |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
164 void oops_do(OopClosure* f); |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
165 |
0 | 166 private: |
167 // Element array. | |
168 volatile E* _elems; | |
169 }; | |
170 | |
171 template<class E> | |
172 GenericTaskQueue<E>::GenericTaskQueue():TaskQueueSuper() { | |
173 assert(sizeof(Age) == sizeof(jint), "Depends on this."); | |
174 } | |
175 | |
176 template<class E> | |
177 void GenericTaskQueue<E>::initialize() { | |
178 _elems = NEW_C_HEAP_ARRAY(E, n()); | |
179 guarantee(_elems != NULL, "Allocation failed."); | |
180 } | |
181 | |
182 template<class E> | |
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
183 void GenericTaskQueue<E>::oops_do(OopClosure* f) { |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
184 // tty->print_cr("START OopTaskQueue::oops_do"); |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
185 int iters = size(); |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
186 juint index = _bottom; |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
187 for (int i = 0; i < iters; ++i) { |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
188 index = decrement_index(index); |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
189 // tty->print_cr(" doing entry %d," INTPTR_T " -> " INTPTR_T, |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
190 // index, &_elems[index], _elems[index]); |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
191 E* t = (E*)&_elems[index]; // cast away volatility |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
192 oop* p = (oop*)t; |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
193 assert((*t)->is_oop_or_null(), "Not an oop or null"); |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
194 f->do_oop(p); |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
195 } |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
196 // tty->print_cr("END OopTaskQueue::oops_do"); |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
197 } |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
198 |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
199 |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
200 template<class E> |
0 | 201 bool GenericTaskQueue<E>::push_slow(E t, juint dirty_n_elems) { |
202 if (dirty_n_elems == n() - 1) { | |
203 // Actually means 0, so do the push. | |
204 juint localBot = _bottom; | |
205 _elems[localBot] = t; | |
206 _bottom = increment_index(localBot); | |
207 return true; | |
208 } else | |
209 return false; | |
210 } | |
211 | |
212 template<class E> | |
213 bool GenericTaskQueue<E>:: | |
214 pop_local_slow(juint localBot, Age oldAge) { | |
215 // This queue was observed to contain exactly one element; either this | |
216 // thread will claim it, or a competing "pop_global". In either case, | |
217 // the queue will be logically empty afterwards. Create a new Age value | |
218 // that represents the empty queue for the given value of "_bottom". (We | |
219 // must also increment "tag" because of the case where "bottom == 1", | |
220 // "top == 0". A pop_global could read the queue element in that case, | |
221 // then have the owner thread do a pop followed by another push. Without | |
222 // the incrementing of "tag", the pop_global's CAS could succeed, | |
223 // allowing it to believe it has claimed the stale element.) | |
224 Age newAge; | |
225 newAge._top = localBot; | |
226 newAge._tag = oldAge.tag() + 1; | |
227 // Perhaps a competing pop_global has already incremented "top", in which | |
228 // case it wins the element. | |
229 if (localBot == oldAge.top()) { | |
230 Age tempAge; | |
231 // No competing pop_global has yet incremented "top"; we'll try to | |
232 // install new_age, thus claiming the element. | |
233 assert(sizeof(Age) == sizeof(jint) && sizeof(jint) == sizeof(juint), | |
234 "Assumption about CAS unit."); | |
235 *(jint*)&tempAge = Atomic::cmpxchg(*(jint*)&newAge, (volatile jint*)&_age, *(jint*)&oldAge); | |
236 if (tempAge == oldAge) { | |
237 // We win. | |
238 assert(dirty_size(localBot, get_top()) != n() - 1, | |
239 "Shouldn't be possible..."); | |
240 return true; | |
241 } | |
242 } | |
243 // We fail; a completing pop_global gets the element. But the queue is | |
244 // empty (and top is greater than bottom.) Fix this representation of | |
245 // the empty queue to become the canonical one. | |
246 set_age(newAge); | |
247 assert(dirty_size(localBot, get_top()) != n() - 1, | |
248 "Shouldn't be possible..."); | |
249 return false; | |
250 } | |
251 | |
252 template<class E> | |
253 bool GenericTaskQueue<E>::pop_global(E& t) { | |
254 Age newAge; | |
255 Age oldAge = get_age(); | |
256 juint localBot = _bottom; | |
257 juint n_elems = size(localBot, oldAge.top()); | |
258 if (n_elems == 0) { | |
259 return false; | |
260 } | |
261 t = _elems[oldAge.top()]; | |
262 newAge = oldAge; | |
263 newAge._top = increment_index(newAge.top()); | |
264 if ( newAge._top == 0 ) newAge._tag++; | |
265 Age resAge; | |
266 *(jint*)&resAge = Atomic::cmpxchg(*(jint*)&newAge, (volatile jint*)&_age, *(jint*)&oldAge); | |
267 // Note that using "_bottom" here might fail, since a pop_local might | |
268 // have decremented it. | |
269 assert(dirty_size(localBot, newAge._top) != n() - 1, | |
270 "Shouldn't be possible..."); | |
271 return (resAge == oldAge); | |
272 } | |
273 | |
274 template<class E> | |
275 GenericTaskQueue<E>::~GenericTaskQueue() { | |
276 FREE_C_HEAP_ARRAY(E, _elems); | |
277 } | |
278 | |
279 // Inherits the typedef of "Task" from above. | |
280 class TaskQueueSetSuper: public CHeapObj { | |
281 protected: | |
282 static int randomParkAndMiller(int* seed0); | |
283 public: | |
284 // Returns "true" if some TaskQueue in the set contains a task. | |
285 virtual bool peek() = 0; | |
286 }; | |
287 | |
288 template<class E> class GenericTaskQueueSet: public TaskQueueSetSuper { | |
289 private: | |
290 int _n; | |
291 GenericTaskQueue<E>** _queues; | |
292 | |
293 public: | |
294 GenericTaskQueueSet(int n) : _n(n) { | |
295 typedef GenericTaskQueue<E>* GenericTaskQueuePtr; | |
296 _queues = NEW_C_HEAP_ARRAY(GenericTaskQueuePtr, n); | |
297 guarantee(_queues != NULL, "Allocation failure."); | |
298 for (int i = 0; i < n; i++) { | |
299 _queues[i] = NULL; | |
300 } | |
301 } | |
302 | |
303 bool steal_1_random(int queue_num, int* seed, E& t); | |
304 bool steal_best_of_2(int queue_num, int* seed, E& t); | |
305 bool steal_best_of_all(int queue_num, int* seed, E& t); | |
306 | |
307 void register_queue(int i, GenericTaskQueue<E>* q); | |
308 | |
309 GenericTaskQueue<E>* queue(int n); | |
310 | |
311 // The thread with queue number "queue_num" (and whose random number seed | |
312 // is at "seed") is trying to steal a task from some other queue. (It | |
313 // may try several queues, according to some configuration parameter.) | |
314 // If some steal succeeds, returns "true" and sets "t" the stolen task, | |
315 // otherwise returns false. | |
316 bool steal(int queue_num, int* seed, E& t); | |
317 | |
318 bool peek(); | |
319 }; | |
320 | |
321 template<class E> | |
322 void GenericTaskQueueSet<E>::register_queue(int i, GenericTaskQueue<E>* q) { | |
323 assert(0 <= i && i < _n, "index out of range."); | |
324 _queues[i] = q; | |
325 } | |
326 | |
327 template<class E> | |
328 GenericTaskQueue<E>* GenericTaskQueueSet<E>::queue(int i) { | |
329 return _queues[i]; | |
330 } | |
331 | |
332 template<class E> | |
333 bool GenericTaskQueueSet<E>::steal(int queue_num, int* seed, E& t) { | |
334 for (int i = 0; i < 2 * _n; i++) | |
335 if (steal_best_of_2(queue_num, seed, t)) | |
336 return true; | |
337 return false; | |
338 } | |
339 | |
340 template<class E> | |
341 bool GenericTaskQueueSet<E>::steal_best_of_all(int queue_num, int* seed, E& t) { | |
342 if (_n > 2) { | |
343 int best_k; | |
344 jint best_sz = 0; | |
345 for (int k = 0; k < _n; k++) { | |
346 if (k == queue_num) continue; | |
347 jint sz = _queues[k]->size(); | |
348 if (sz > best_sz) { | |
349 best_sz = sz; | |
350 best_k = k; | |
351 } | |
352 } | |
353 return best_sz > 0 && _queues[best_k]->pop_global(t); | |
354 } else if (_n == 2) { | |
355 // Just try the other one. | |
356 int k = (queue_num + 1) % 2; | |
357 return _queues[k]->pop_global(t); | |
358 } else { | |
359 assert(_n == 1, "can't be zero."); | |
360 return false; | |
361 } | |
362 } | |
363 | |
364 template<class E> | |
365 bool GenericTaskQueueSet<E>::steal_1_random(int queue_num, int* seed, E& t) { | |
366 if (_n > 2) { | |
367 int k = queue_num; | |
368 while (k == queue_num) k = randomParkAndMiller(seed) % _n; | |
369 return _queues[2]->pop_global(t); | |
370 } else if (_n == 2) { | |
371 // Just try the other one. | |
372 int k = (queue_num + 1) % 2; | |
373 return _queues[k]->pop_global(t); | |
374 } else { | |
375 assert(_n == 1, "can't be zero."); | |
376 return false; | |
377 } | |
378 } | |
379 | |
380 template<class E> | |
381 bool GenericTaskQueueSet<E>::steal_best_of_2(int queue_num, int* seed, E& t) { | |
382 if (_n > 2) { | |
383 int k1 = queue_num; | |
384 while (k1 == queue_num) k1 = randomParkAndMiller(seed) % _n; | |
385 int k2 = queue_num; | |
386 while (k2 == queue_num || k2 == k1) k2 = randomParkAndMiller(seed) % _n; | |
387 // Sample both and try the larger. | |
388 juint sz1 = _queues[k1]->size(); | |
389 juint sz2 = _queues[k2]->size(); | |
390 if (sz2 > sz1) return _queues[k2]->pop_global(t); | |
391 else return _queues[k1]->pop_global(t); | |
392 } else if (_n == 2) { | |
393 // Just try the other one. | |
394 int k = (queue_num + 1) % 2; | |
395 return _queues[k]->pop_global(t); | |
396 } else { | |
397 assert(_n == 1, "can't be zero."); | |
398 return false; | |
399 } | |
400 } | |
401 | |
402 template<class E> | |
403 bool GenericTaskQueueSet<E>::peek() { | |
404 // Try all the queues. | |
405 for (int j = 0; j < _n; j++) { | |
406 if (_queues[j]->peek()) | |
407 return true; | |
408 } | |
409 return false; | |
410 } | |
411 | |
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
412 // When to terminate from the termination protocol. |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
413 class TerminatorTerminator: public CHeapObj { |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
414 public: |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
415 virtual bool should_exit_termination() = 0; |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
416 }; |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
417 |
0 | 418 // A class to aid in the termination of a set of parallel tasks using |
419 // TaskQueueSet's for work stealing. | |
420 | |
421 class ParallelTaskTerminator: public StackObj { | |
422 private: | |
423 int _n_threads; | |
424 TaskQueueSetSuper* _queue_set; | |
425 jint _offered_termination; | |
426 | |
427 bool peek_in_queue_set(); | |
428 protected: | |
429 virtual void yield(); | |
430 void sleep(uint millis); | |
431 | |
432 public: | |
433 | |
434 // "n_threads" is the number of threads to be terminated. "queue_set" is a | |
435 // queue sets of work queues of other threads. | |
436 ParallelTaskTerminator(int n_threads, TaskQueueSetSuper* queue_set); | |
437 | |
438 // The current thread has no work, and is ready to terminate if everyone | |
439 // else is. If returns "true", all threads are terminated. If returns | |
440 // "false", available work has been observed in one of the task queues, | |
441 // so the global task is not complete. | |
342
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
442 bool offer_termination() { |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
443 return offer_termination(NULL); |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
444 } |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
445 |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
446 // As above, but it also terminates of the should_exit_termination() |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
447 // method of the terminator parameter returns true. If terminator is |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
448 // NULL, then it is ignored. |
37f87013dfd8
6711316: Open source the Garbage-First garbage collector
ysr
parents:
113
diff
changeset
|
449 bool offer_termination(TerminatorTerminator* terminator); |
0 | 450 |
451 // Reset the terminator, so that it may be reused again. | |
452 // The caller is responsible for ensuring that this is done | |
453 // in an MT-safe manner, once the previous round of use of | |
454 // the terminator is finished. | |
455 void reset_for_reuse(); | |
456 | |
457 }; | |
458 | |
459 #define SIMPLE_STACK 0 | |
460 | |
461 template<class E> inline bool GenericTaskQueue<E>::push(E t) { | |
462 #if SIMPLE_STACK | |
463 juint localBot = _bottom; | |
464 if (_bottom < max_elems()) { | |
465 _elems[localBot] = t; | |
466 _bottom = localBot + 1; | |
467 return true; | |
468 } else { | |
469 return false; | |
470 } | |
471 #else | |
472 juint localBot = _bottom; | |
473 assert((localBot >= 0) && (localBot < n()), "_bottom out of range."); | |
474 jushort top = get_top(); | |
475 juint dirty_n_elems = dirty_size(localBot, top); | |
476 assert((dirty_n_elems >= 0) && (dirty_n_elems < n()), | |
477 "n_elems out of range."); | |
478 if (dirty_n_elems < max_elems()) { | |
479 _elems[localBot] = t; | |
480 _bottom = increment_index(localBot); | |
481 return true; | |
482 } else { | |
483 return push_slow(t, dirty_n_elems); | |
484 } | |
485 #endif | |
486 } | |
487 | |
488 template<class E> inline bool GenericTaskQueue<E>::pop_local(E& t) { | |
489 #if SIMPLE_STACK | |
490 juint localBot = _bottom; | |
491 assert(localBot > 0, "precondition."); | |
492 localBot--; | |
493 t = _elems[localBot]; | |
494 _bottom = localBot; | |
495 return true; | |
496 #else | |
497 juint localBot = _bottom; | |
498 // This value cannot be n-1. That can only occur as a result of | |
499 // the assignment to bottom in this method. If it does, this method | |
500 // resets the size( to 0 before the next call (which is sequential, | |
501 // since this is pop_local.) | |
502 juint dirty_n_elems = dirty_size(localBot, get_top()); | |
503 assert(dirty_n_elems != n() - 1, "Shouldn't be possible..."); | |
504 if (dirty_n_elems == 0) return false; | |
505 localBot = decrement_index(localBot); | |
506 _bottom = localBot; | |
507 // This is necessary to prevent any read below from being reordered | |
508 // before the store just above. | |
509 OrderAccess::fence(); | |
510 t = _elems[localBot]; | |
511 // This is a second read of "age"; the "size()" above is the first. | |
512 // If there's still at least one element in the queue, based on the | |
513 // "_bottom" and "age" we've read, then there can be no interference with | |
514 // a "pop_global" operation, and we're done. | |
515 juint tp = get_top(); | |
516 if (size(localBot, tp) > 0) { | |
517 assert(dirty_size(localBot, tp) != n() - 1, | |
518 "Shouldn't be possible..."); | |
519 return true; | |
520 } else { | |
521 // Otherwise, the queue contained exactly one element; we take the slow | |
522 // path. | |
523 return pop_local_slow(localBot, get_age()); | |
524 } | |
525 #endif | |
526 } | |
527 | |
528 typedef oop Task; | |
529 typedef GenericTaskQueue<Task> OopTaskQueue; | |
530 typedef GenericTaskQueueSet<Task> OopTaskQueueSet; | |
531 | |
113
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
532 |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
533 #define COMPRESSED_OOP_MASK 1 |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
534 |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
535 // This is a container class for either an oop* or a narrowOop*. |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
536 // Both are pushed onto a task queue and the consumer will test is_narrow() |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
537 // to determine which should be processed. |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
538 class StarTask { |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
539 void* _holder; // either union oop* or narrowOop* |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
540 public: |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
541 StarTask(narrowOop *p) { _holder = (void *)((uintptr_t)p | COMPRESSED_OOP_MASK); } |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
542 StarTask(oop *p) { _holder = (void*)p; } |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
543 StarTask() { _holder = NULL; } |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
544 operator oop*() { return (oop*)_holder; } |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
545 operator narrowOop*() { |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
546 return (narrowOop*)((uintptr_t)_holder & ~COMPRESSED_OOP_MASK); |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
547 } |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
548 |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
549 // Operators to preserve const/volatile in assignments required by gcc |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
550 void operator=(const volatile StarTask& t) volatile { _holder = t._holder; } |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
551 |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
552 bool is_narrow() const { |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
553 return (((uintptr_t)_holder & COMPRESSED_OOP_MASK) != 0); |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
554 } |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
555 }; |
ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
0
diff
changeset
|
556 |
0 | 557 typedef GenericTaskQueue<StarTask> OopStarTaskQueue; |
558 typedef GenericTaskQueueSet<StarTask> OopStarTaskQueueSet; | |
559 | |
560 typedef size_t ChunkTask; // index for chunk | |
561 typedef GenericTaskQueue<ChunkTask> ChunkTaskQueue; | |
562 typedef GenericTaskQueueSet<ChunkTask> ChunkTaskQueueSet; | |
563 | |
564 class ChunkTaskQueueWithOverflow: public CHeapObj { | |
565 protected: | |
566 ChunkTaskQueue _chunk_queue; | |
567 GrowableArray<ChunkTask>* _overflow_stack; | |
568 | |
569 public: | |
570 ChunkTaskQueueWithOverflow() : _overflow_stack(NULL) {} | |
571 // Initialize both stealable queue and overflow | |
572 void initialize(); | |
573 // Save first to stealable queue and then to overflow | |
574 void save(ChunkTask t); | |
575 // Retrieve first from overflow and then from stealable queue | |
576 bool retrieve(ChunkTask& chunk_index); | |
577 // Retrieve from stealable queue | |
578 bool retrieve_from_stealable_queue(ChunkTask& chunk_index); | |
579 // Retrieve from overflow | |
580 bool retrieve_from_overflow(ChunkTask& chunk_index); | |
581 bool is_empty(); | |
582 bool stealable_is_empty(); | |
583 bool overflow_is_empty(); | |
584 juint stealable_size() { return _chunk_queue.size(); } | |
585 ChunkTaskQueue* task_queue() { return &_chunk_queue; } | |
586 }; | |
587 | |
588 #define USE_ChunkTaskQueueWithOverflow |