44 |
|
* tasks that are never joined. |
45 |
|
* |
46 |
|
* <p>A static {@link #commonPool} is available and appropriate for |
47 |
< |
* most applications. The common pool is constructed upon first |
48 |
< |
* access, or upon usage by any ForkJoinTask that is not explictly |
49 |
< |
* submitted to a specified pool. Using the common pool normally |
50 |
< |
* reduces resource usage (its threads are slowly reclaimed during |
51 |
< |
* periods of non-use, and reinstated upon subsequent use). The |
52 |
< |
* common pool is by default constructed with default parameters, but |
53 |
< |
* these may be controlled by setting any or all of the three |
54 |
< |
* properties {@code |
47 |
> |
* most applications. The common pool is used by any ForkJoinTask that |
48 |
> |
* is not explicitly submitted to a specified pool. Using the common |
49 |
> |
* pool normally reduces resource usage (its threads are slowly |
50 |
> |
* reclaimed during periods of non-use, and reinstated upon subsequent |
51 |
> |
* use). The common pool is by default constructed with default |
52 |
> |
* parameters, but these may be controlled by setting any or all of |
53 |
> |
* the three properties {@code |
54 |
|
* java.util.concurrent.ForkJoinPool.common.{parallelism, |
55 |
|
* threadFactory, exceptionHandler}}. |
56 |
|
* |
236 |
|
* when locked remains available to check consistency. |
237 |
|
* |
238 |
|
* Recording WorkQueues. WorkQueues are recorded in the |
239 |
< |
* "workQueues" array that is created upon pool construction and |
240 |
< |
* expanded if necessary. Updates to the array while recording |
241 |
< |
* new workers and unrecording terminated ones are protected from |
242 |
< |
* each other by a lock but the array is otherwise concurrently |
243 |
< |
* readable, and accessed directly. To simplify index-based |
244 |
< |
* operations, the array size is always a power of two, and all |
245 |
< |
* readers must tolerate null slots. Shared (submission) queues |
246 |
< |
* are at even indices, worker queues at odd indices. Grouping |
247 |
< |
* them together in this way simplifies and speeds up task |
249 |
< |
* scanning. |
239 |
> |
* "workQueues" array that is created upon first use and expanded |
240 |
> |
* if necessary. Updates to the array while recording new workers |
241 |
> |
* and unrecording terminated ones are protected from each other |
242 |
> |
* by a lock but the array is otherwise concurrently readable, and |
243 |
> |
* accessed directly. To simplify index-based operations, the |
244 |
> |
* array size is always a power of two, and all readers must |
245 |
> |
* tolerate null slots. Shared (submission) queues are at even |
246 |
> |
* indices, worker queues at odd indices. Grouping them together |
247 |
> |
* in this way simplifies and speeds up task scanning. |
248 |
|
* |
249 |
|
* All worker thread creation is on-demand, triggered by task |
250 |
|
* submissions, replacement of terminated workers, and/or |
502 |
|
} |
503 |
|
|
504 |
|
/** |
507 |
– |
* A simple non-reentrant lock used for exclusion when managing |
508 |
– |
* queues and workers. We use a custom lock so that we can readily |
509 |
– |
* probe lock state in constructions that check among alternative |
510 |
– |
* actions. The lock is normally only very briefly held, and |
511 |
– |
* sometimes treated as a spinlock, but other usages block to |
512 |
– |
* reduce overall contention in those cases where locked code |
513 |
– |
* bodies perform allocation/resizing. |
514 |
– |
*/ |
515 |
– |
static final class Mutex extends AbstractQueuedSynchronizer { |
516 |
– |
public final boolean tryAcquire(int ignore) { |
517 |
– |
return compareAndSetState(0, 1); |
518 |
– |
} |
519 |
– |
public final boolean tryRelease(int ignore) { |
520 |
– |
setState(0); |
521 |
– |
return true; |
522 |
– |
} |
523 |
– |
public final void lock() { acquire(0); } |
524 |
– |
public final void unlock() { release(0); } |
525 |
– |
public final boolean isHeldExclusively() { return getState() == 1; } |
526 |
– |
public final Condition newCondition() { return new ConditionObject(); } |
527 |
– |
} |
528 |
– |
|
529 |
– |
/** |
505 |
|
* Class for artificial tasks that are used to replace the target |
506 |
|
* of local joins if they are removed from an interior queue slot |
507 |
|
* in WorkQueue.tryRemoveAndExec. We don't need the proxy to |
789 |
|
|
790 |
|
/** |
791 |
|
* Version of tryUnpush for shared queues; called by non-FJ |
792 |
< |
* submitters. Conservatively fails to unpush if all workers |
818 |
< |
* are active unless there are multiple tasks in queue. |
792 |
> |
* submitters after prechecking that task probably exists. |
793 |
|
*/ |
794 |
< |
final boolean trySharedUnpush(ForkJoinTask<?> task, ForkJoinPool p) { |
794 |
> |
final boolean trySharedUnpush(ForkJoinTask<?> t) { |
795 |
|
boolean success = false; |
796 |
< |
if (task != null && top != base && runState == 0 && |
823 |
< |
U.compareAndSwapInt(this, RUNSTATE, 0, 1)) { |
796 |
> |
if (runState == 0 && U.compareAndSwapInt(this, RUNSTATE, 0, 1)) { |
797 |
|
try { |
798 |
< |
ForkJoinTask<?>[] a; int n, s; |
799 |
< |
if ((a = array) != null && (n = (s = top) - base) > 0 && |
800 |
< |
(n > 1 || p == null || (int)(p.ctl >> AC_SHIFT) < 0)) { |
801 |
< |
int j = (((a.length - 1) & --s) << ASHIFT) + ABASE; |
802 |
< |
if (U.getObjectVolatile(a, j) == task && |
803 |
< |
U.compareAndSwapObject(a, j, task, null)) { |
831 |
< |
top = s; |
832 |
< |
success = true; |
833 |
< |
} |
798 |
> |
ForkJoinTask<?>[] a; int s; |
799 |
> |
if ((a = array) != null && (s = top) != base && |
800 |
> |
U.compareAndSwapObject |
801 |
> |
(a, (((a.length - 1) & --s) << ASHIFT) + ABASE, t, null)) { |
802 |
> |
top = s; |
803 |
> |
success = true; |
804 |
|
} |
805 |
|
} finally { |
806 |
|
runState = 0; // unlock |
1083 |
|
public static final ForkJoinWorkerThreadFactory |
1084 |
|
defaultForkJoinWorkerThreadFactory; |
1085 |
|
|
1086 |
+ |
|
1087 |
+ |
/** Property prefix for constructing common pool */ |
1088 |
+ |
private static final String propPrefix = |
1089 |
+ |
"java.util.concurrent.ForkJoinPool.common."; |
1090 |
+ |
|
1091 |
+ |
/** |
1092 |
+ |
* Common (static) pool. Non-null for public use unless a static |
1093 |
+ |
* construction exception, but internal usages must null-check on |
1094 |
+ |
* use. |
1095 |
+ |
*/ |
1096 |
+ |
static final ForkJoinPool commonPool; |
1097 |
+ |
|
1098 |
+ |
/** |
1099 |
+ |
* Common pool parallelism. Must equal commonPool.parallelism. |
1100 |
+ |
*/ |
1101 |
+ |
static final int commonPoolParallelism; |
1102 |
+ |
|
1103 |
|
/** |
1104 |
|
* Generator for assigning sequence numbers as pool names. |
1105 |
|
*/ |
1124 |
|
*/ |
1125 |
|
private static final ThreadSubmitter submitters; |
1126 |
|
|
1140 |
– |
/** Common default pool */ |
1141 |
– |
static volatile ForkJoinPool commonPool; |
1142 |
– |
|
1143 |
– |
// commonPool construction parameters |
1144 |
– |
private static final String propPrefix = |
1145 |
– |
"java.util.concurrent.ForkJoinPool.common."; |
1146 |
– |
private static final Thread.UncaughtExceptionHandler commonPoolUEH; |
1147 |
– |
private static final ForkJoinWorkerThreadFactory commonPoolFactory; |
1148 |
– |
static final int commonPoolParallelism; |
1149 |
– |
|
1150 |
– |
/** Static initialization lock */ |
1151 |
– |
private static final Mutex initializationLock; |
1152 |
– |
|
1127 |
|
// static constants |
1128 |
|
|
1129 |
|
/** |
1130 |
< |
* Initial timeout value (in nanoseconds) for the tread triggering |
1130 |
> |
* Initial timeout value (in nanoseconds) for the thread triggering |
1131 |
|
* quiescence to park waiting for new work. On timeout, the thread |
1132 |
|
* will instead try to shrink the number of workers. |
1133 |
|
*/ |
1256 |
|
* empirically works OK on current JVMs. |
1257 |
|
*/ |
1258 |
|
|
1259 |
+ |
volatile long stealCount; // collects worker counts |
1260 |
|
volatile long ctl; // main pool control |
1261 |
|
final int parallelism; // parallelism level |
1262 |
|
final int localMode; // per-worker scheduling mode |
1263 |
+ |
volatile int nextWorkerNumber; // to create worker name string |
1264 |
|
final int submitMask; // submit queue index bound |
1265 |
|
int nextSeed; // for initializing worker seeds |
1266 |
+ |
volatile int mainLock; // spinlock for array updates |
1267 |
|
volatile int runState; // shutdown status and seq |
1268 |
|
WorkQueue[] workQueues; // main registry |
1292 |
– |
final Mutex lock; // for registration |
1293 |
– |
final Condition termination; // for awaitTermination |
1269 |
|
final ForkJoinWorkerThreadFactory factory; // factory for new workers |
1270 |
|
final Thread.UncaughtExceptionHandler ueh; // per-worker UEH |
1271 |
< |
final AtomicLong stealCount; // collect counts when terminated |
1272 |
< |
final AtomicInteger nextWorkerNumber; // to create worker name string |
1273 |
< |
String workerNamePrefix; // to create worker name string |
1271 |
> |
final String workerNamePrefix; // to create worker name string |
1272 |
> |
|
1273 |
> |
/* |
1274 |
> |
* Mechanics for main lock protecting worker array updates. Uses |
1275 |
> |
* the same strategy as ConcurrentHashMap bins -- a spinLock for |
1276 |
> |
* normal cases, but falling back to builtin lock when (rarely) |
1277 |
> |
* needed. See internal ConcurrentHashMap documentation for |
1278 |
> |
* explanation. |
1279 |
> |
*/ |
1280 |
> |
|
1281 |
> |
static final int LOCK_WAITING = 2; // bit to indicate need for signal |
1282 |
> |
static final int MAX_LOCK_SPINS = 1 << 8; |
1283 |
> |
|
1284 |
> |
private void tryAwaitMainLock() { |
1285 |
> |
int spins = MAX_LOCK_SPINS, r = 0, h; |
1286 |
> |
while (((h = mainLock) & 1) != 0) { |
1287 |
> |
if (r == 0) |
1288 |
> |
r = ThreadLocalRandom.current().nextInt(); // randomize spins |
1289 |
> |
else if (spins >= 0) { |
1290 |
> |
r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift |
1291 |
> |
if (r >= 0) |
1292 |
> |
--spins; |
1293 |
> |
} |
1294 |
> |
else if (U.compareAndSwapInt(this, MAINLOCK, h, h | LOCK_WAITING)) { |
1295 |
> |
synchronized (this) { |
1296 |
> |
if ((mainLock & LOCK_WAITING) != 0) { |
1297 |
> |
try { |
1298 |
> |
wait(); |
1299 |
> |
} catch (InterruptedException ie) { |
1300 |
> |
Thread.currentThread().interrupt(); |
1301 |
> |
} |
1302 |
> |
} |
1303 |
> |
else |
1304 |
> |
notifyAll(); // possibly won race vs signaller |
1305 |
> |
} |
1306 |
> |
break; |
1307 |
> |
} |
1308 |
> |
} |
1309 |
> |
} |
1310 |
|
|
1311 |
|
// Creating, registering, and deregistering workers |
1312 |
|
|
1334 |
|
* ForkJoinWorkerThread. |
1335 |
|
*/ |
1336 |
|
final String nextWorkerName() { |
1337 |
< |
return workerNamePrefix.concat |
1338 |
< |
(Integer.toString(nextWorkerNumber.addAndGet(1))); |
1337 |
> |
int n; |
1338 |
> |
do {} while(!U.compareAndSwapInt(this, NEXTWORKERNUMBER, |
1339 |
> |
n = nextWorkerNumber, ++n)); |
1340 |
> |
return workerNamePrefix.concat(Integer.toString(n)); |
1341 |
|
} |
1342 |
|
|
1343 |
|
/** |
1350 |
|
* @param w the worker's queue |
1351 |
|
*/ |
1352 |
|
final void registerWorker(WorkQueue w) { |
1353 |
< |
Mutex lock = this.lock; |
1354 |
< |
lock.lock(); |
1353 |
> |
while (!U.compareAndSwapInt(this, MAINLOCK, 0, 1)) |
1354 |
> |
tryAwaitMainLock(); |
1355 |
|
try { |
1356 |
< |
WorkQueue[] ws = workQueues; |
1357 |
< |
if (w != null && ws != null) { // skip on shutdown/failure |
1356 |
> |
WorkQueue[] ws; |
1357 |
> |
if ((ws = workQueues) == null) |
1358 |
> |
ws = workQueues = new WorkQueue[submitMask + 1]; |
1359 |
> |
if (w != null) { |
1360 |
|
int rs, n = ws.length, m = n - 1; |
1361 |
|
int s = nextSeed += SEED_INCREMENT; // rarely-colliding sequence |
1362 |
|
w.seed = (s == 0) ? 1 : s; // ensure non-zero seed |
1377 |
|
runState = ((rs = runState) & SHUTDOWN) | ((rs + 2) & ~SHUTDOWN); |
1378 |
|
} |
1379 |
|
} finally { |
1380 |
< |
lock.unlock(); |
1380 |
> |
if (!U.compareAndSwapInt(this, MAINLOCK, 1, 0)) { |
1381 |
> |
mainLock = 0; |
1382 |
> |
synchronized (this) { notifyAll(); }; |
1383 |
> |
} |
1384 |
|
} |
1385 |
+ |
|
1386 |
|
} |
1387 |
|
|
1388 |
|
/** |
1395 |
|
* @param ex the exception causing failure, or null if none |
1396 |
|
*/ |
1397 |
|
final void deregisterWorker(ForkJoinWorkerThread wt, Throwable ex) { |
1379 |
– |
Mutex lock = this.lock; |
1398 |
|
WorkQueue w = null; |
1399 |
|
if (wt != null && (w = wt.workQueue) != null) { |
1400 |
|
w.runState = -1; // ensure runState is set |
1401 |
< |
stealCount.getAndAdd(w.totalSteals + w.nsteals); |
1401 |
> |
long steals = w.totalSteals + w.nsteals, sc; |
1402 |
> |
do {} while(!U.compareAndSwapLong(this, STEALCOUNT, |
1403 |
> |
sc = stealCount, sc + steals)); |
1404 |
|
int idx = w.poolIndex; |
1405 |
< |
lock.lock(); |
1406 |
< |
try { // remove record from array |
1405 |
> |
while (!U.compareAndSwapInt(this, MAINLOCK, 0, 1)) |
1406 |
> |
tryAwaitMainLock(); |
1407 |
> |
try { |
1408 |
|
WorkQueue[] ws = workQueues; |
1409 |
|
if (ws != null && idx >= 0 && idx < ws.length && ws[idx] == w) |
1410 |
|
ws[idx] = null; |
1411 |
|
} finally { |
1412 |
< |
lock.unlock(); |
1412 |
> |
if (!U.compareAndSwapInt(this, MAINLOCK, 1, 0)) { |
1413 |
> |
mainLock = 0; |
1414 |
> |
synchronized (this) { notifyAll(); }; |
1415 |
> |
} |
1416 |
|
} |
1417 |
|
} |
1418 |
|
|
1451 |
|
for (int r = s.seed, m = submitMask;;) { |
1452 |
|
WorkQueue[] ws; WorkQueue q; |
1453 |
|
int k = r & m & SQMASK; // use only even indices |
1454 |
< |
if (runState < 0 || (ws = workQueues) == null || ws.length <= k) |
1454 |
> |
if (runState < 0) |
1455 |
|
throw new RejectedExecutionException(); // shutting down |
1456 |
+ |
else if ((ws = workQueues) == null || ws.length <= k) { |
1457 |
+ |
while (!U.compareAndSwapInt(this, MAINLOCK, 0, 1)) |
1458 |
+ |
tryAwaitMainLock(); |
1459 |
+ |
try { |
1460 |
+ |
if (workQueues == null) |
1461 |
+ |
workQueues = new WorkQueue[submitMask + 1]; |
1462 |
+ |
} finally { |
1463 |
+ |
if (!U.compareAndSwapInt(this, MAINLOCK, 1, 0)) { |
1464 |
+ |
mainLock = 0; |
1465 |
+ |
synchronized (this) { notifyAll(); }; |
1466 |
+ |
} |
1467 |
+ |
} |
1468 |
+ |
} |
1469 |
|
else if ((q = ws[k]) == null) { // create new queue |
1470 |
|
WorkQueue nq = new WorkQueue(this, null, SHARED_QUEUE); |
1471 |
< |
Mutex lock = this.lock; // construct outside lock |
1472 |
< |
lock.lock(); |
1473 |
< |
try { // recheck under lock |
1471 |
> |
while (!U.compareAndSwapInt(this, MAINLOCK, 0, 1)) |
1472 |
> |
tryAwaitMainLock(); |
1473 |
> |
try { |
1474 |
|
int rs = runState; // to update seq |
1475 |
|
if (ws == workQueues && ws[k] == null) { |
1476 |
|
ws[k] = nq; |
1477 |
|
runState = ((rs & SHUTDOWN) | ((rs + 2) & ~SHUTDOWN)); |
1478 |
|
} |
1479 |
|
} finally { |
1480 |
< |
lock.unlock(); |
1480 |
> |
if (!U.compareAndSwapInt(this, MAINLOCK, 1, 0)) { |
1481 |
> |
mainLock = 0; |
1482 |
> |
synchronized (this) { notifyAll(); }; |
1483 |
> |
} |
1484 |
|
} |
1485 |
|
} |
1486 |
|
else if (q.trySharedPush(task)) { |
1503 |
|
static void submitToCommonPool(ForkJoinTask<?> task) { |
1504 |
|
ForkJoinPool p; |
1505 |
|
if ((p = commonPool) == null) |
1506 |
< |
p = ensureCommonPool(); |
1506 |
> |
throw new RejectedExecutionException("Common Pool Unavailable"); |
1507 |
|
p.doSubmit(task); |
1508 |
|
} |
1509 |
|
|
1517 |
|
* @return true if successful |
1518 |
|
*/ |
1519 |
|
static boolean tryUnsubmitFromCommonPool(ForkJoinTask<?> task) { |
1520 |
+ |
// Peek, looking for task and eligibility before |
1521 |
+ |
// using trySharedUnpush to actually take it under lock |
1522 |
|
ForkJoinPool p; WorkQueue[] ws; WorkQueue q; |
1523 |
+ |
ForkJoinTask<?>[] a; int t, s, n; |
1524 |
|
int k = submitters.get().seed & SQMASK; |
1525 |
|
return ((p = commonPool) != null && |
1526 |
|
(ws = p.workQueues) != null && |
1527 |
|
ws.length > (k &= p.submitMask) && |
1528 |
|
(q = ws[k]) != null && |
1529 |
< |
q.trySharedUnpush(task, p)); |
1529 |
> |
(a = q.array) != null && |
1530 |
> |
(n = (t = q.top) - q.base) > 0 && |
1531 |
> |
(n > 1 || (int)(p.ctl >> AC_SHIFT) < 0) && |
1532 |
> |
(s = t - 1) >= 0 && s < a.length && a[s] == task && |
1533 |
> |
q.trySharedUnpush(task)); |
1534 |
|
} |
1535 |
|
|
1536 |
|
// Maintaining ctl counts |
2004 |
|
*/ |
2005 |
|
private WorkQueue findNonEmptyStealQueue(WorkQueue w) { |
2006 |
|
// Similar to loop in scan(), but ignoring submissions |
2007 |
< |
int r; |
1961 |
< |
if (w == null) // allow external callers |
1962 |
< |
r = ThreadLocalRandom.current().nextInt(); |
1963 |
< |
else { |
1964 |
< |
r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5; |
1965 |
< |
} |
2007 |
> |
int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5; |
2008 |
|
int step = (r >>> 16) | 1; |
2009 |
|
for (WorkQueue[] ws;;) { |
2010 |
|
int rs = runState, m; |
2145 |
|
* @return true if now terminating or terminated |
2146 |
|
*/ |
2147 |
|
private boolean tryTerminate(boolean now, boolean enable) { |
2106 |
– |
Mutex lock = this.lock; |
2148 |
|
for (long c;;) { |
2149 |
|
if (((c = ctl) & STOP_BIT) != 0) { // already terminating |
2150 |
|
if ((short)(c >>> TC_SHIFT) == -parallelism) { |
2151 |
< |
lock.lock(); // don't need try/finally |
2152 |
< |
termination.signalAll(); // signal when 0 workers |
2153 |
< |
lock.unlock(); |
2151 |
> |
synchronized(this) { |
2152 |
> |
notifyAll(); // signal when 0 workers |
2153 |
> |
} |
2154 |
|
} |
2155 |
|
return true; |
2156 |
|
} |
2157 |
|
if (runState >= 0) { // not yet enabled |
2158 |
|
if (!enable) |
2159 |
|
return false; |
2160 |
< |
lock.lock(); |
2161 |
< |
runState |= SHUTDOWN; |
2162 |
< |
lock.unlock(); |
2160 |
> |
while (!U.compareAndSwapInt(this, MAINLOCK, 0, 1)) |
2161 |
> |
tryAwaitMainLock(); |
2162 |
> |
try { |
2163 |
> |
runState |= SHUTDOWN; |
2164 |
> |
} finally { |
2165 |
> |
if (!U.compareAndSwapInt(this, MAINLOCK, 1, 0)) { |
2166 |
> |
mainLock = 0; |
2167 |
> |
synchronized (this) { notifyAll(); }; |
2168 |
> |
} |
2169 |
> |
} |
2170 |
|
} |
2171 |
|
if (!now) { // check if idle & no tasks |
2172 |
|
if ((int)(c >> AC_SHIFT) != -parallelism || |
2299 |
|
// Use nearest power 2 for workQueues size. See Hackers Delight sec 3.2. |
2300 |
|
int n = parallelism - 1; |
2301 |
|
n |= n >>> 1; n |= n >>> 2; n |= n >>> 4; n |= n >>> 8; n |= n >>> 16; |
2302 |
< |
int size = (n + 1) << 1; // #slots = 2*#workers |
2255 |
< |
this.submitMask = size - 1; // room for max # of submit queues |
2256 |
< |
this.workQueues = new WorkQueue[size]; |
2257 |
< |
this.termination = (this.lock = new Mutex()).newCondition(); |
2258 |
< |
this.stealCount = new AtomicLong(); |
2259 |
< |
this.nextWorkerNumber = new AtomicInteger(); |
2302 |
> |
this.submitMask = ((n + 1) << 1) - 1; |
2303 |
|
int pn = poolNumberGenerator.incrementAndGet(); |
2304 |
|
StringBuilder sb = new StringBuilder("ForkJoinPool-"); |
2305 |
|
sb.append(Integer.toString(pn)); |
2306 |
|
sb.append("-worker-"); |
2307 |
|
this.workerNamePrefix = sb.toString(); |
2265 |
– |
lock.lock(); |
2308 |
|
this.runState = 1; // set init flag |
2267 |
– |
lock.unlock(); |
2309 |
|
} |
2310 |
|
|
2311 |
|
/** |
2312 |
< |
* Returns the common pool instance |
2312 |
> |
* Constructor for common pool, suitable only for static initialization. |
2313 |
> |
* Basically the same as above, but uses smallest possible initial footprint. |
2314 |
> |
*/ |
2315 |
> |
ForkJoinPool(int parallelism, int submitMask, |
2316 |
> |
ForkJoinWorkerThreadFactory factory, |
2317 |
> |
Thread.UncaughtExceptionHandler handler) { |
2318 |
> |
this.factory = factory; |
2319 |
> |
this.ueh = handler; |
2320 |
> |
this.submitMask = submitMask; |
2321 |
> |
this.parallelism = parallelism; |
2322 |
> |
long np = (long)(-parallelism); |
2323 |
> |
this.ctl = ((np << AC_SHIFT) & AC_MASK) | ((np << TC_SHIFT) & TC_MASK); |
2324 |
> |
this.localMode = LIFO_QUEUE; |
2325 |
> |
this.workerNamePrefix = "ForkJoinPool.commonPool-worker-"; |
2326 |
> |
this.runState = 1; |
2327 |
> |
} |
2328 |
> |
|
2329 |
> |
/** |
2330 |
> |
* Returns the common pool instance. |
2331 |
|
* |
2332 |
|
* @return the common pool instance |
2333 |
|
*/ |
2334 |
|
public static ForkJoinPool commonPool() { |
2335 |
|
ForkJoinPool p; |
2336 |
< |
return (p = commonPool) != null? p : ensureCommonPool(); |
2337 |
< |
} |
2279 |
< |
|
2280 |
< |
private static ForkJoinPool ensureCommonPool() { |
2281 |
< |
ForkJoinPool p; |
2282 |
< |
if ((p = commonPool) == null) { |
2283 |
< |
final Mutex lock = initializationLock; |
2284 |
< |
lock.lock(); |
2285 |
< |
try { |
2286 |
< |
if ((p = commonPool) == null) { |
2287 |
< |
p = commonPool = new ForkJoinPool(commonPoolParallelism, |
2288 |
< |
commonPoolFactory, |
2289 |
< |
commonPoolUEH, false); |
2290 |
< |
// use a more informative name string for workers |
2291 |
< |
p.workerNamePrefix = "ForkJoinPool.commonPool-worker-"; |
2292 |
< |
} |
2293 |
< |
} finally { |
2294 |
< |
lock.unlock(); |
2295 |
< |
} |
2296 |
< |
} |
2336 |
> |
if ((p = commonPool) == null) |
2337 |
> |
throw new Error("Common Pool Unavailable"); |
2338 |
|
return p; |
2339 |
|
} |
2340 |
|
|
2600 |
|
* @return the number of steals |
2601 |
|
*/ |
2602 |
|
public long getStealCount() { |
2603 |
< |
long count = stealCount.get(); |
2603 |
> |
long count = stealCount; |
2604 |
|
WorkQueue[] ws; WorkQueue w; |
2605 |
|
if ((ws = workQueues) != null) { |
2606 |
|
for (int i = 1; i < ws.length; i += 2) { |
2730 |
|
public String toString() { |
2731 |
|
// Use a single pass through workQueues to collect counts |
2732 |
|
long qt = 0L, qs = 0L; int rc = 0; |
2733 |
< |
long st = stealCount.get(); |
2733 |
> |
long st = stealCount; |
2734 |
|
long c = ctl; |
2735 |
|
WorkQueue[] ws; WorkQueue w; |
2736 |
|
if ((ws = workQueues) != null) { |
2868 |
|
public boolean awaitTermination(long timeout, TimeUnit unit) |
2869 |
|
throws InterruptedException { |
2870 |
|
long nanos = unit.toNanos(timeout); |
2871 |
< |
final Mutex lock = this.lock; |
2872 |
< |
lock.lock(); |
2873 |
< |
try { |
2874 |
< |
for (;;) { |
2875 |
< |
if (isTerminated()) |
2876 |
< |
return true; |
2877 |
< |
if (nanos <= 0) |
2878 |
< |
return false; |
2879 |
< |
nanos = termination.awaitNanos(nanos); |
2871 |
> |
if (isTerminated()) |
2872 |
> |
return true; |
2873 |
> |
long startTime = System.nanoTime(); |
2874 |
> |
boolean terminated = false; |
2875 |
> |
synchronized(this) { |
2876 |
> |
for (long waitTime = nanos, millis = 0L;;) { |
2877 |
> |
if (terminated = isTerminated() || |
2878 |
> |
waitTime <= 0L || |
2879 |
> |
(millis = unit.toMillis(waitTime)) <= 0L) |
2880 |
> |
break; |
2881 |
> |
wait(millis); |
2882 |
> |
waitTime = nanos - (System.nanoTime() - startTime); |
2883 |
|
} |
2840 |
– |
} finally { |
2841 |
– |
lock.unlock(); |
2884 |
|
} |
2885 |
+ |
return terminated; |
2886 |
|
} |
2887 |
|
|
2888 |
|
/** |
3014 |
|
private static final long PARKBLOCKER; |
3015 |
|
private static final int ABASE; |
3016 |
|
private static final int ASHIFT; |
3017 |
+ |
private static final long NEXTWORKERNUMBER; |
3018 |
+ |
private static final long STEALCOUNT; |
3019 |
+ |
private static final long MAINLOCK; |
3020 |
|
|
3021 |
|
static { |
3022 |
|
poolNumberGenerator = new AtomicInteger(); |
3025 |
|
defaultForkJoinWorkerThreadFactory = |
3026 |
|
new DefaultForkJoinWorkerThreadFactory(); |
3027 |
|
submitters = new ThreadSubmitter(); |
2982 |
– |
initializationLock = new Mutex(); |
3028 |
|
int s; |
3029 |
|
try { |
3030 |
|
U = getUnsafe(); |
3032 |
|
Class<?> ak = ForkJoinTask[].class; |
3033 |
|
CTL = U.objectFieldOffset |
3034 |
|
(k.getDeclaredField("ctl")); |
3035 |
+ |
NEXTWORKERNUMBER = U.objectFieldOffset |
3036 |
+ |
(k.getDeclaredField("nextWorkerNumber")); |
3037 |
+ |
STEALCOUNT = U.objectFieldOffset |
3038 |
+ |
(k.getDeclaredField("stealCount")); |
3039 |
+ |
MAINLOCK = U.objectFieldOffset |
3040 |
+ |
(k.getDeclaredField("mainLock")); |
3041 |
|
Class<?> tk = Thread.class; |
3042 |
|
PARKBLOCKER = U.objectFieldOffset |
3043 |
|
(tk.getDeclaredField("parkBlocker")); |
3044 |
|
ABASE = U.arrayBaseOffset(ak); |
3045 |
|
s = U.arrayIndexScale(ak); |
3046 |
+ |
ASHIFT = 31 - Integer.numberOfLeadingZeros(s); |
3047 |
|
} catch (Exception e) { |
3048 |
|
throw new Error(e); |
3049 |
|
} |
3050 |
|
if ((s & (s-1)) != 0) |
3051 |
|
throw new Error("data type scale not a power of two"); |
3052 |
< |
ASHIFT = 31 - Integer.numberOfLeadingZeros(s); |
3001 |
< |
|
3002 |
< |
// Establish configuration for default pool |
3003 |
< |
try { |
3052 |
> |
try { // Establish common pool |
3053 |
|
String pp = System.getProperty(propPrefix + "parallelism"); |
3054 |
|
String fp = System.getProperty(propPrefix + "threadFactory"); |
3055 |
|
String up = System.getProperty(propPrefix + "exceptionHandler"); |
3056 |
+ |
ForkJoinWorkerThreadFactory fac = (fp == null) ? |
3057 |
+ |
defaultForkJoinWorkerThreadFactory : |
3058 |
+ |
((ForkJoinWorkerThreadFactory)ClassLoader. |
3059 |
+ |
getSystemClassLoader().loadClass(fp).newInstance()); |
3060 |
+ |
Thread.UncaughtExceptionHandler ueh = (up == null)? null : |
3061 |
+ |
((Thread.UncaughtExceptionHandler)ClassLoader. |
3062 |
+ |
getSystemClassLoader().loadClass(up).newInstance()); |
3063 |
|
int par; |
3064 |
|
if ((pp == null || (par = Integer.parseInt(pp)) <= 0)) |
3065 |
|
par = Runtime.getRuntime().availableProcessors(); |
3066 |
+ |
if (par > MAX_CAP) |
3067 |
+ |
par = MAX_CAP; |
3068 |
|
commonPoolParallelism = par; |
3069 |
< |
if (fp != null) |
3070 |
< |
commonPoolFactory = (ForkJoinWorkerThreadFactory) |
3071 |
< |
ClassLoader.getSystemClassLoader().loadClass(fp).newInstance(); |
3072 |
< |
else |
3073 |
< |
commonPoolFactory = defaultForkJoinWorkerThreadFactory; |
3016 |
< |
if (up != null) |
3017 |
< |
commonPoolUEH = (Thread.UncaughtExceptionHandler) |
3018 |
< |
ClassLoader.getSystemClassLoader().loadClass(up).newInstance(); |
3019 |
< |
else |
3020 |
< |
commonPoolUEH = null; |
3069 |
> |
int n = par - 1; // precompute submit mask |
3070 |
> |
n |= n >>> 1; n |= n >>> 2; n |= n >>> 4; |
3071 |
> |
n |= n >>> 8; n |= n >>> 16; |
3072 |
> |
int mask = ((n + 1) << 1) - 1; |
3073 |
> |
commonPool = new ForkJoinPool(par, mask, fac, ueh); |
3074 |
|
} catch (Exception e) { |
3075 |
|
throw new Error(e); |
3076 |
|
} |