ViewVC Help

View File | Revision Log | Show Annotations | Download File | Root Listing

root/jsr166/jsr166/src/jsr166e/ForkJoinPool.java

Comparing jsr166/src/jsr166e/ForkJoinPool.java (file contents):
Revision 1.7 by dl, Sun Oct 28 22:35:45 2012 UTC vs.
Revision 1.11 by dl, Wed Oct 31 12:49:13 2012 UTC

#	Line 44 | Line 44 | import java.util.concurrent.locks.Condit
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		*
#	Line 237 | Line 236 | public class ForkJoinPool extends Abstra
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
#	Line 504 | Line 502 | public class ForkJoinPool extends Abstra
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
#	Line 717 | Line 692 | public class ForkJoinPool extends Abstra
692
693		/**
694		* Takes next task, if one exists, in LIFO order.  Call only
695	<	* by owner in unshared queues. (We do not have a shared
721	<	* version of this method because it is never needed.)
695	>	* by owner in unshared queues.
696		*/
697		final ForkJoinTask<?> pop() {
698		ForkJoinTask<?>[] a; ForkJoinTask<?> t; int m;
#	Line 736 | Line 710 | public class ForkJoinPool extends Abstra
710		return null;
711		}
712
713	+	final ForkJoinTask<?> sharedPop() {
714	+	ForkJoinTask<?> task = null;
715	+	if (runState == 0 && U.compareAndSwapInt(this, RUNSTATE, 0, 1)) {
716	+	try {
717	+	ForkJoinTask<?>[] a; int m;
718	+	if ((a = array) != null && (m = a.length - 1) >= 0) {
719	+	for (int s; (s = top - 1) - base >= 0;) {
720	+	long j = ((m & s) << ASHIFT) + ABASE;
721	+	ForkJoinTask<?> t =
722	+	(ForkJoinTask<?>)U.getObject(a, j);
723	+	if (t == null)
724	+	break;
725	+	if (U.compareAndSwapObject(a, j, t, null)) {
726	+	top = s;
727	+	task = t;
728	+	break;
729	+	}
730	+	}
731	+	}
732	+	} finally {
733	+	runState = 0;
734	+	}
735	+	}
736	+	return task;
737	+	}
738	+
739	+
740		/**
741		* Takes a task in FIFO order if b is base of queue and a task
742		* can be claimed without contention. Specialized versions
#	Line 814 | Line 815 | public class ForkJoinPool extends Abstra
815
816		/**
817		* Version of tryUnpush for shared queues; called by non-FJ
818	<	* submitters. Conservatively fails to unpush if all workers
818	<	* are active unless there are multiple tasks in queue.
818	>	* submitters after prechecking that task probably exists.
819		*/
820	<	final boolean trySharedUnpush(ForkJoinTask<?> task, ForkJoinPool p) {
820	>	final boolean trySharedUnpush(ForkJoinTask<?> t) {
821		boolean success = false;
822	<	if (task != null && top != base && runState == 0 &&
823	<	U.compareAndSwapInt(this, RUNSTATE, 0, 1)) {
822	>	if (runState == 0 && U.compareAndSwapInt(this, RUNSTATE, 0, 1)) {
823		try {
824	<	ForkJoinTask<?>[] a; int n, s;
825	<	if ((a = array) != null && (n = (s = top) - base) > 0 &&
826	<	(n > 1 || p == null || (int)(p.ctl >> AC_SHIFT) < 0)) {
827	<	int j = (((a.length - 1) & --s) << ASHIFT) + ABASE;
828	<	if (U.getObjectVolatile(a, j) == task &&
829	<	U.compareAndSwapObject(a, j, task, null)) {
831	<	top = s;
832	<	success = true;
833	<	}
824	>	ForkJoinTask<?>[] a; int s;
825	>	if ((a = array) != null && (s = top) != base &&
826	>	U.compareAndSwapObject
827	>	(a, (((a.length - 1) & --s) << ASHIFT) + ABASE, t, null)) {
828	>	top = s;
829	>	success = true;
830		}
831		} finally {
832		runState = 0;                         // unlock
#	Line 914 | Line 910 | public class ForkJoinPool extends Abstra
910		return seed = r ^= r << 5;
911		}
912
913	<	// Execution methods
913	>	// Specialized execution methods
914
915		/**
916		* Pops and runs tasks until empty.
#	Line 993 | Line 989 | public class ForkJoinPool extends Abstra
989		}
990
991		/**
992	+	* Version of shared pop that takes top element only if it
993	+	* its root is the given CountedCompleter.
994	+	*/
995	+	final CountedCompleter<?> sharedPopCC(CountedCompleter<?> root) {
996	+	CountedCompleter<?> task = null;
997	+	if (runState == 0 && U.compareAndSwapInt(this, RUNSTATE, 0, 1)) {
998	+	try {
999	+	ForkJoinTask<?>[] a; int m;
1000	+	if ((a = array) != null && (m = a.length - 1) >= 0) {
1001	+	outer:for (int s; (s = top - 1) - base >= 0;) {
1002	+	long j = ((m & s) << ASHIFT) + ABASE;
1003	+	ForkJoinTask<?> t =
1004	+	(ForkJoinTask<?>)U.getObject(a, j);
1005	+	if (t == null || !(t instanceof CountedCompleter))
1006	+	break;
1007	+	CountedCompleter<?> cc = (CountedCompleter<?>)t;
1008	+	for (CountedCompleter<?> q = cc, p;;) {
1009	+	if (q == root) {
1010	+	if (U.compareAndSwapObject(a, j, cc, null)) {
1011	+	top = s;
1012	+	task = cc;
1013	+	break outer;
1014	+	}
1015	+	break;
1016	+	}
1017	+	if ((p = q.completer) == null)
1018	+	break outer;
1019	+	q = p;
1020	+	}
1021	+	}
1022	+	}
1023	+	} finally {
1024	+	runState = 0;
1025	+	}
1026	+	}
1027	+	return task;
1028	+	}
1029	+
1030	+	/**
1031		* Executes a top-level task and any local tasks remaining
1032		* after execution.
1033		*/
#	Line 1113 | Line 1148 | public class ForkJoinPool extends Abstra
1148		public static final ForkJoinWorkerThreadFactory
1149		defaultForkJoinWorkerThreadFactory;
1150
1151	+	/** Property prefix for constructing common pool */
1152	+	private static final String propPrefix =
1153	+	"java.util.concurrent.ForkJoinPool.common.";
1154	+
1155	+	/**
1156	+	* Common (static) pool. Non-null for public use unless a static
1157	+	* construction exception, but internal usages must null-check on
1158	+	* use.
1159	+	*/
1160	+	static final ForkJoinPool commonPool;
1161	+
1162	+	/**
1163	+	* Common pool parallelism. Must equal commonPool.parallelism.
1164	+	*/
1165	+	static final int commonPoolParallelism;
1166	+
1167		/**
1168		* Generator for assigning sequence numbers as pool names.
1169		*/
#	Line 1137 | Line 1188 | public class ForkJoinPool extends Abstra
1188		*/
1189		private static final ThreadSubmitter submitters;
1190
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	–
1191		// static constants
1192
1193		/**
1194	<	* Initial timeout value (in nanoseconds) for the tread triggering
1194	>	* Initial timeout value (in nanoseconds) for the thread triggering
1195		* quiescence to park waiting for new work. On timeout, the thread
1196		* will instead try to shrink the number of workers.
1197		*/
#	Line 1282 | Line 1320 | public class ForkJoinPool extends Abstra
1320		* empirically works OK on current JVMs.
1321		*/
1322
1323	+	volatile long stealCount;                  // collects worker counts
1324		volatile long ctl;                         // main pool control
1325		final int parallelism;                     // parallelism level
1326		final int localMode;                       // per-worker scheduling mode
1327	+	volatile int nextWorkerNumber;             // to create worker name string
1328		final int submitMask;                      // submit queue index bound
1329		int nextSeed;                              // for initializing worker seeds
1330	+	volatile int mainLock;                     // spinlock for array updates
1331		volatile int runState;                     // shutdown status and seq
1332		WorkQueue[] workQueues;                    // main registry
1292	–	final Mutex lock;                          // for registration
1293	–	final Condition termination;               // for awaitTermination
1333		final ForkJoinWorkerThreadFactory factory; // factory for new workers
1334		final Thread.UncaughtExceptionHandler ueh; // per-worker UEH
1335	<	final AtomicLong stealCount;               // collect counts when terminated
1336	<	final AtomicInteger nextWorkerNumber;      // to create worker name string
1337	<	String workerNamePrefix;                   // to create worker name string
1335	>	final String workerNamePrefix;             // to create worker name string
1336	>
1337	>	/*
1338	>	* Mechanics for main lock protecting worker array updates.  Uses
1339	>	* the same strategy as ConcurrentHashMap bins -- a spinLock for
1340	>	* normal cases, but falling back to builtin lock when (rarely)
1341	>	* needed.  See internal ConcurrentHashMap documentation for
1342	>	* explanation.
1343	>	*/
1344	>
1345	>	static final int LOCK_WAITING = 2; // bit to indicate need for signal
1346	>	static final int MAX_LOCK_SPINS = 1 << 8;
1347	>
1348	>	private void tryAwaitMainLock() {
1349	>	int spins = MAX_LOCK_SPINS, r = 0, h;
1350	>	while (((h = mainLock) & 1) != 0) {
1351	>	if (r == 0)
1352	>	r = ThreadLocalRandom.current().nextInt(); // randomize spins
1353	>	else if (spins >= 0) {
1354	>	r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
1355	>	if (r >= 0)
1356	>	--spins;
1357	>	}
1358	>	else if (U.compareAndSwapInt(this, MAINLOCK, h, h | LOCK_WAITING)) {
1359	>	synchronized (this) {
1360	>	if ((mainLock & LOCK_WAITING) != 0) {
1361	>	try {
1362	>	wait();
1363	>	} catch (InterruptedException ie) {
1364	>	try {
1365	>	Thread.currentThread().interrupt();
1366	>	} catch (SecurityException ignore) {
1367	>	}
1368	>	}
1369	>	}
1370	>	else
1371	>	notifyAll(); // possibly won race vs signaller
1372	>	}
1373	>	break;
1374	>	}
1375	>	}
1376	>	}
1377
1378		//  Creating, registering, and deregistering workers
1379
#	Line 1323 | Line 1401 | public class ForkJoinPool extends Abstra
1401		* ForkJoinWorkerThread.
1402		*/
1403		final String nextWorkerName() {
1404	<	return workerNamePrefix.concat
1405	<	(Integer.toString(nextWorkerNumber.addAndGet(1)));
1404	>	int n;
1405	>	do {} while (!U.compareAndSwapInt(this, NEXTWORKERNUMBER,
1406	>	n = nextWorkerNumber, ++n));
1407	>	return workerNamePrefix.concat(Integer.toString(n));
1408		}
1409
1410		/**
#	Line 1337 | Line 1417 | public class ForkJoinPool extends Abstra
1417		* @param w the worker's queue
1418		*/
1419		final void registerWorker(WorkQueue w) {
1420	<	Mutex lock = this.lock;
1421	<	lock.lock();
1420	>	while (!U.compareAndSwapInt(this, MAINLOCK, 0, 1))
1421	>	tryAwaitMainLock();
1422		try {
1423	<	WorkQueue[] ws = workQueues;
1424	<	if (w != null && ws != null) {          // skip on shutdown/failure
1423	>	WorkQueue[] ws;
1424	>	if ((ws = workQueues) == null)
1425	>	ws = workQueues = new WorkQueue[submitMask + 1];
1426	>	if (w != null) {
1427		int rs, n =  ws.length, m = n - 1;
1428		int s = nextSeed += SEED_INCREMENT; // rarely-colliding sequence
1429		w.seed = (s == 0) ? 1 : s;          // ensure non-zero seed
#	Line 1362 | Line 1444 | public class ForkJoinPool extends Abstra
1444		runState = ((rs = runState) & SHUTDOWN) | ((rs + 2) & ~SHUTDOWN);
1445		}
1446		} finally {
1447	<	lock.unlock();
1447	>	if (!U.compareAndSwapInt(this, MAINLOCK, 1, 0)) {
1448	>	mainLock = 0;
1449	>	synchronized (this) { notifyAll(); };
1450	>	}
1451		}
1452		}
1453
#	Line 1376 | Line 1461 | public class ForkJoinPool extends Abstra
1461		* @param ex the exception causing failure, or null if none
1462		*/
1463		final void deregisterWorker(ForkJoinWorkerThread wt, Throwable ex) {
1379	–	Mutex lock = this.lock;
1464		WorkQueue w = null;
1465		if (wt != null && (w = wt.workQueue) != null) {
1466		w.runState = -1;                // ensure runState is set
1467	<	stealCount.getAndAdd(w.totalSteals + w.nsteals);
1467	>	long steals = w.totalSteals + w.nsteals, sc;
1468	>	do {} while (!U.compareAndSwapLong(this, STEALCOUNT,
1469	>	sc = stealCount, sc + steals));
1470		int idx = w.poolIndex;
1471	<	lock.lock();
1472	<	try {                           // remove record from array
1471	>	while (!U.compareAndSwapInt(this, MAINLOCK, 0, 1))
1472	>	tryAwaitMainLock();
1473	>	try {
1474		WorkQueue[] ws = workQueues;
1475		if (ws != null && idx >= 0 && idx < ws.length && ws[idx] == w)
1476		ws[idx] = null;
1477		} finally {
1478	<	lock.unlock();
1478	>	if (!U.compareAndSwapInt(this, MAINLOCK, 1, 0)) {
1479	>	mainLock = 0;
1480	>	synchronized (this) { notifyAll(); };
1481	>	}
1482		}
1483		}
1484
#	Line 1407 | Line 1497 | public class ForkJoinPool extends Abstra
1497		}
1498
1499		if (ex != null)                     // rethrow
1500	<	U.throwException(ex);
1500	>	ForkJoinTask.rethrow(ex);
1501		}
1502
1503		// Submissions
#	Line 1427 | Line 1517 | public class ForkJoinPool extends Abstra
1517		for (int r = s.seed, m = submitMask;;) {
1518		WorkQueue[] ws; WorkQueue q;
1519		int k = r & m & SQMASK;          // use only even indices
1520	<	if (runState < 0 || (ws = workQueues) == null || ws.length <= k)
1520	>	if (runState < 0)
1521		throw new RejectedExecutionException(); // shutting down
1522	+	else if ((ws = workQueues) == null || ws.length <= k) {
1523	+	while (!U.compareAndSwapInt(this, MAINLOCK, 0, 1))
1524	+	tryAwaitMainLock();
1525	+	try {
1526	+	if (workQueues == null)
1527	+	workQueues = new WorkQueue[submitMask + 1];
1528	+	} finally {
1529	+	if (!U.compareAndSwapInt(this, MAINLOCK, 1, 0)) {
1530	+	mainLock = 0;
1531	+	synchronized (this) { notifyAll(); };
1532	+	}
1533	+	}
1534	+	}
1535		else if ((q = ws[k]) == null) {  // create new queue
1536		WorkQueue nq = new WorkQueue(this, null, SHARED_QUEUE);
1537	<	Mutex lock = this.lock;      // construct outside lock
1538	<	lock.lock();
1539	<	try {                        // recheck under lock
1537	>	while (!U.compareAndSwapInt(this, MAINLOCK, 0, 1))
1538	>	tryAwaitMainLock();
1539	>	try {
1540		int rs = runState;       // to update seq
1541		if (ws == workQueues && ws[k] == null) {
1542		ws[k] = nq;
1543		runState = ((rs & SHUTDOWN) | ((rs + 2) & ~SHUTDOWN));
1544		}
1545		} finally {
1546	<	lock.unlock();
1546	>	if (!U.compareAndSwapInt(this, MAINLOCK, 1, 0)) {
1547	>	mainLock = 0;
1548	>	synchronized (this) { notifyAll(); };
1549	>	}
1550		}
1551		}
1552		else if (q.trySharedPush(task)) {
#	Line 1463 | Line 1569 | public class ForkJoinPool extends Abstra
1569		static void submitToCommonPool(ForkJoinTask<?> task) {
1570		ForkJoinPool p;
1571		if ((p = commonPool) == null)
1572	<	p = ensureCommonPool();
1572	>	throw new RejectedExecutionException("Common Pool Unavailable");
1573		p.doSubmit(task);
1574		}
1575
#	Line 1477 | Line 1583 | public class ForkJoinPool extends Abstra
1583		* @return true if successful
1584		*/
1585		static boolean tryUnsubmitFromCommonPool(ForkJoinTask<?> task) {
1586	<	ForkJoinPool p; WorkQueue[] ws; WorkQueue q;
1587	<	int k = submitters.get().seed & SQMASK;
1588	<	return ((p = commonPool) != null &&
1589	<	(ws = p.workQueues) != null &&
1590	<	ws.length > (k &= p.submitMask) &&
1591	<	(q = ws[k]) != null &&
1592	<	q.trySharedUnpush(task, p));
1586	>	// If not oversaturating platform, peek, looking for task and
1587	>	// eligibility before using trySharedUnpush to actually take
1588	>	// it under lock
1589	>	ForkJoinPool p; WorkQueue[] ws; WorkQueue w, q;
1590	>	ForkJoinTask<?>[] a; int ac, s, m;
1591	>	if ((p = commonPool) != null && (ws = p.workQueues) != null) {
1592	>	int k = submitters.get().seed & p.submitMask & SQMASK;
1593	>	if ((m = ws.length - 1) >= k && (q = ws[k]) != null &&
1594	>	(ac = (int)(p.ctl >> AC_SHIFT)) <= 0) {
1595	>	if (ac == 0) { // double check if all workers active
1596	>	for (int i = 1; i <= m; i += 2) {
1597	>	if ((w = ws[i]) != null && w.parker != null) {
1598	>	ac = -1;
1599	>	break;
1600	>	}
1601	>	}
1602	>	}
1603	>	return (ac < 0 && (a = q.array) != null &&
1604	>	(s = q.top - 1) - q.base >= 0 &&
1605	>	s >= 0 && s < a.length &&
1606	>	a[s] == task &&
1607	>	q.trySharedUnpush(task));
1608	>	}
1609	>	}
1610	>	return false;
1611	>	}
1612	>
1613	>	/**
1614	>	* Tries to pop and run a task within same computation from common pool
1615	>	*/
1616	>	static void popAndExecCCFromCommonPool(CountedCompleter<?> cc) {
1617	>	ForkJoinPool p; WorkQueue[] ws; WorkQueue q, w; int m, ac;
1618	>	CountedCompleter<?> par, task;
1619	>	if ((p = commonPool) != null && (ws = p.workQueues) != null) {
1620	>	while ((par = cc.completer) != null) // find root
1621	>	cc = par;
1622	>	int k = submitters.get().seed & p.submitMask & SQMASK;
1623	>	if ((m = ws.length - 1) >= k && (q = ws[k]) != null &&
1624	>	(ac = (int)(p.ctl >> AC_SHIFT)) <= 0) {
1625	>	if (ac == 0) {
1626	>	for (int i = 1; i <= m; i += 2) {
1627	>	if ((w = ws[i]) != null && w.parker != null) {
1628	>	ac = -1;
1629	>	break;
1630	>	}
1631	>	}
1632	>	}
1633	>	if (ac < 0 && q.top - q.base > 0 &&
1634	>	(task = q.sharedPopCC(cc)) != null)
1635	>	task.exec();
1636	>	}
1637	>	}
1638		}
1639
1640		// Maintaining ctl counts
#	Line 1957 | Line 2108 | public class ForkJoinPool extends Abstra
2108		*/
2109		private WorkQueue findNonEmptyStealQueue(WorkQueue w) {
2110		// Similar to loop in scan(), but ignoring submissions
2111	<	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	<	}
2111	>	int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
2112		int step = (r >>> 16) | 1;
2113		for (WorkQueue[] ws;;) {
2114		int rs = runState, m;
#	Line 2026 | Line 2172 | public class ForkJoinPool extends Abstra
2172		* Restricted version of helpQuiescePool for non-FJ callers
2173		*/
2174		static void externalHelpQuiescePool() {
2175	<	ForkJoinPool p; WorkQueue[] ws; WorkQueue w, q;
2176	<	ForkJoinTask<?> t; int b;
2175	>	ForkJoinPool p; WorkQueue[] ws; WorkQueue q, sq;
2176	>	ForkJoinTask<?>[] a; int b;
2177	>	ForkJoinTask<?> t = null;
2178		int k = submitters.get().seed & SQMASK;
2179		if ((p = commonPool) != null &&
2180		(ws = p.workQueues) != null &&
2181		ws.length > (k &= p.submitMask) &&
2182	<	(w = ws[k]) != null &&
2183	<	(q = p.findNonEmptyStealQueue(w)) != null &&
2184	<	(b = q.base) - q.top < 0 &&
2185	<	(t = q.pollAt(b)) != null)
2186	<	t.doExec();
2182	>	(q = ws[k]) != null) {
2183	>	while (q.top - q.base > 0) {
2184	>	if ((t = q.sharedPop()) != null)
2185	>	break;
2186	>	}
2187	>	if (t == null && (sq = p.findNonEmptyStealQueue(q)) != null &&
2188	>	(b = sq.base) - sq.top < 0)
2189	>	t = sq.pollAt(b);
2190	>	if (t != null)
2191	>	t.doExec();
2192	>	}
2193		}
2194
2195		/**
#	Line 2078 | Line 2231 | public class ForkJoinPool extends Abstra
2231		static int getEstimatedSubmitterQueueLength() {
2232		ForkJoinPool p; WorkQueue[] ws; WorkQueue q;
2233		int k = submitters.get().seed & SQMASK;
2234	<	return ((p = commonPool) != null &&
2082	<	p.runState >= 0 &&
2083	<	(ws = p.workQueues) != null &&
2234	>	return ((p = commonPool) != null && (ws = p.workQueues) != null &&
2235		ws.length > (k &= p.submitMask) &&
2236		(q = ws[k]) != null) ?
2237		q.queueSize() : 0;
#	Line 2103 | Line 2254 | public class ForkJoinPool extends Abstra
2254		* @return true if now terminating or terminated
2255		*/
2256		private boolean tryTerminate(boolean now, boolean enable) {
2106	–	Mutex lock = this.lock;
2257		for (long c;;) {
2258		if (((c = ctl) & STOP_BIT) != 0) {      // already terminating
2259		if ((short)(c >>> TC_SHIFT) == -parallelism) {
2260	<	lock.lock();                    // don't need try/finally
2261	<	termination.signalAll();        // signal when 0 workers
2262	<	lock.unlock();
2260	>	synchronized (this) {
2261	>	notifyAll();                // signal when 0 workers
2262	>	}
2263		}
2264		return true;
2265		}
2266		if (runState >= 0) {                    // not yet enabled
2267		if (!enable)
2268		return false;
2269	<	lock.lock();
2270	<	runState |= SHUTDOWN;
2271	<	lock.unlock();
2269	>	while (!U.compareAndSwapInt(this, MAINLOCK, 0, 1))
2270	>	tryAwaitMainLock();
2271	>	try {
2272	>	runState |= SHUTDOWN;
2273	>	} finally {
2274	>	if (!U.compareAndSwapInt(this, MAINLOCK, 1, 0)) {
2275	>	mainLock = 0;
2276	>	synchronized (this) { notifyAll(); };
2277	>	}
2278	>	}
2279		}
2280		if (!now) {                             // check if idle & no tasks
2281		if ((int)(c >> AC_SHIFT) != -parallelism ||
#	Line 2251 | Line 2408 | public class ForkJoinPool extends Abstra
2408		// Use nearest power 2 for workQueues size. See Hackers Delight sec 3.2.
2409		int n = parallelism - 1;
2410		n |= n >>> 1; n |= n >>> 2; n |= n >>> 4; n |= n >>> 8; n |= n >>> 16;
2411	<	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();
2411	>	this.submitMask = ((n + 1) << 1) - 1;
2412		int pn = poolNumberGenerator.incrementAndGet();
2413		StringBuilder sb = new StringBuilder("ForkJoinPool-");
2414		sb.append(Integer.toString(pn));
2415		sb.append("-worker-");
2416		this.workerNamePrefix = sb.toString();
2265	–	lock.lock();
2417		this.runState = 1;              // set init flag
2267	–	lock.unlock();
2418		}
2419
2420		/**
2421	<	* Returns the common pool instance
2421	>	* Constructor for common pool, suitable only for static initialization.
2422	>	* Basically the same as above, but uses smallest possible initial footprint.
2423	>	*/
2424	>	ForkJoinPool(int parallelism, int submitMask,
2425	>	ForkJoinWorkerThreadFactory factory,
2426	>	Thread.UncaughtExceptionHandler handler) {
2427	>	this.factory = factory;
2428	>	this.ueh = handler;
2429	>	this.submitMask = submitMask;
2430	>	this.parallelism = parallelism;
2431	>	long np = (long)(-parallelism);
2432	>	this.ctl = ((np << AC_SHIFT) & AC_MASK) | ((np << TC_SHIFT) & TC_MASK);
2433	>	this.localMode = LIFO_QUEUE;
2434	>	this.workerNamePrefix = "ForkJoinPool.commonPool-worker-";
2435	>	this.runState = 1;
2436	>	}
2437	>
2438	>	/**
2439	>	* Returns the common pool instance.
2440		*
2441		* @return the common pool instance
2442		*/
2443		public static ForkJoinPool commonPool() {
2444		ForkJoinPool p;
2445	<	return (p = commonPool) != null? p : ensureCommonPool();
2446	<	}
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	<	}
2445	>	if ((p = commonPool) == null)
2446	>	throw new Error("Common Pool Unavailable");
2447		return p;
2448		}
2449
#	Line 2559 | Line 2709 | public class ForkJoinPool extends Abstra
2709		* @return the number of steals
2710		*/
2711		public long getStealCount() {
2712	<	long count = stealCount.get();
2712	>	long count = stealCount;
2713		WorkQueue[] ws; WorkQueue w;
2714		if ((ws = workQueues) != null) {
2715		for (int i = 1; i < ws.length; i += 2) {
#	Line 2689 | Line 2839 | public class ForkJoinPool extends Abstra
2839		public String toString() {
2840		// Use a single pass through workQueues to collect counts
2841		long qt = 0L, qs = 0L; int rc = 0;
2842	<	long st = stealCount.get();
2842	>	long st = stealCount;
2843		long c = ctl;
2844		WorkQueue[] ws; WorkQueue w;
2845		if ((ws = workQueues) != null) {
#	Line 2827 | Line 2977 | public class ForkJoinPool extends Abstra
2977		public boolean awaitTermination(long timeout, TimeUnit unit)
2978		throws InterruptedException {
2979		long nanos = unit.toNanos(timeout);
2980	<	final Mutex lock = this.lock;
2981	<	lock.lock();
2982	<	try {
2983	<	for (;;) {
2984	<	if (isTerminated())
2985	<	return true;
2986	<	if (nanos <= 0)
2987	<	return false;
2988	<	nanos = termination.awaitNanos(nanos);
2980	>	if (isTerminated())
2981	>	return true;
2982	>	long startTime = System.nanoTime();
2983	>	boolean terminated = false;
2984	>	synchronized (this) {
2985	>	for (long waitTime = nanos, millis = 0L;;) {
2986	>	if (terminated = isTerminated() ||
2987	>	waitTime <= 0L ||
2988	>	(millis = unit.toMillis(waitTime)) <= 0L)
2989	>	break;
2990	>	wait(millis);
2991	>	waitTime = nanos - (System.nanoTime() - startTime);
2992		}
2840	–	} finally {
2841	–	lock.unlock();
2993		}
2994	+	return terminated;
2995		}
2996
2997		/**
#	Line 2971 | Line 3123 | public class ForkJoinPool extends Abstra
3123		private static final long PARKBLOCKER;
3124		private static final int ABASE;
3125		private static final int ASHIFT;
3126	+	private static final long NEXTWORKERNUMBER;
3127	+	private static final long STEALCOUNT;
3128	+	private static final long MAINLOCK;
3129
3130		static {
3131		poolNumberGenerator = new AtomicInteger();
#	Line 2979 | Line 3134 | public class ForkJoinPool extends Abstra
3134		defaultForkJoinWorkerThreadFactory =
3135		new DefaultForkJoinWorkerThreadFactory();
3136		submitters = new ThreadSubmitter();
2982	–	initializationLock = new Mutex();
3137		int s;
3138		try {
3139		U = getUnsafe();
#	Line 2987 | Line 3141 | public class ForkJoinPool extends Abstra
3141		Class<?> ak = ForkJoinTask[].class;
3142		CTL = U.objectFieldOffset
3143		(k.getDeclaredField("ctl"));
3144	+	NEXTWORKERNUMBER = U.objectFieldOffset
3145	+	(k.getDeclaredField("nextWorkerNumber"));
3146	+	STEALCOUNT = U.objectFieldOffset
3147	+	(k.getDeclaredField("stealCount"));
3148	+	MAINLOCK = U.objectFieldOffset
3149	+	(k.getDeclaredField("mainLock"));
3150		Class<?> tk = Thread.class;
3151		PARKBLOCKER = U.objectFieldOffset
3152		(tk.getDeclaredField("parkBlocker"));
3153		ABASE = U.arrayBaseOffset(ak);
3154		s = U.arrayIndexScale(ak);
3155	+	ASHIFT = 31 - Integer.numberOfLeadingZeros(s);
3156		} catch (Exception e) {
3157		throw new Error(e);
3158		}
3159		if ((s & (s-1)) != 0)
3160		throw new Error("data type scale not a power of two");
3161	<	ASHIFT = 31 - Integer.numberOfLeadingZeros(s);
3001	<
3002	<	// Establish configuration for default pool
3003	<	try {
3161	>	try { // Establish common pool
3162		String pp = System.getProperty(propPrefix + "parallelism");
3163		String fp = System.getProperty(propPrefix + "threadFactory");
3164		String up = System.getProperty(propPrefix + "exceptionHandler");
3165	+	ForkJoinWorkerThreadFactory fac = (fp == null) ?
3166	+	defaultForkJoinWorkerThreadFactory :
3167	+	((ForkJoinWorkerThreadFactory)ClassLoader.
3168	+	getSystemClassLoader().loadClass(fp).newInstance());
3169	+	Thread.UncaughtExceptionHandler ueh = (up == null) ? null :
3170	+	((Thread.UncaughtExceptionHandler)ClassLoader.
3171	+	getSystemClassLoader().loadClass(up).newInstance());
3172		int par;
3173		if ((pp == null || (par = Integer.parseInt(pp)) <= 0))
3174		par = Runtime.getRuntime().availableProcessors();
3175	+	if (par > MAX_CAP)
3176	+	par = MAX_CAP;
3177		commonPoolParallelism = par;
3178	<	if (fp != null)
3179	<	commonPoolFactory = (ForkJoinWorkerThreadFactory)
3180	<	ClassLoader.getSystemClassLoader().loadClass(fp).newInstance();
3181	<	else
3182	<	commonPoolFactory = defaultForkJoinWorkerThreadFactory;
3016	<	if (up != null)
3017	<	commonPoolUEH = (Thread.UncaughtExceptionHandler)
3018	<	ClassLoader.getSystemClassLoader().loadClass(up).newInstance();
3019	<	else
3020	<	commonPoolUEH = null;
3178	>	int n = par - 1; // precompute submit mask
3179	>	n |= n >>> 1; n |= n >>> 2; n |= n >>> 4;
3180	>	n |= n >>> 8; n |= n >>> 16;
3181	>	int mask = ((n + 1) << 1) - 1;
3182	>	commonPool = new ForkJoinPool(par, mask, fac, ueh);
3183		} catch (Exception e) {
3184		throw new Error(e);
3185		}

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines