ViewVC Help

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

root/jsr166/jsr166/src/jsr166y/Phaser.java

Comparing jsr166/src/jsr166y/Phaser.java (file contents):
Revision 1.49 by dl, Fri Nov 5 23:01:47 2010 UTC vs.
Revision 1.50 by dl, Sat Nov 6 16:12:10 2010 UTC

#	Line 298 | Line 298 | public class Phaser {
298		* use two of them, alternating across even and odd phases.
299		* Subphasers share queues with root to speed up releases.
300		*/
301	<	private final AtomicReference<QNode> evenQ = new AtomicReference<QNode>();
302	<	private final AtomicReference<QNode> oddQ  = new AtomicReference<QNode>();
301	>	private final AtomicReference<QNode> evenQ;
302	>	private final AtomicReference<QNode> oddQ;
303
304		private AtomicReference<QNode> queueFor(int phase) {
305	<	Phaser r = root;
306	<	return ((phase & 1) == 0) ? r.evenQ : r.oddQ;
305	>	return ((phase & 1) == 0) ? evenQ : oddQ;
306		}
307
308		/**
#	Line 325 | Line 324 | public class Phaser {
324		while ((phase = phaseOf(s)) >= 0 &&
325		(rootPhase = phaseOf(root.state)) != phase &&
326		(rootPhase < 0 || unarrivedOf(s) == 0)) {
327	<	long parentState = par.getReconciledState();
328	<	int parentPhase = phaseOf(parentState);
329	<	int parties = partiesOf(s);
330	<	long next = trippedStateFor(parentPhase, parties);
331	<	if (phaseOf(root.state) == rootPhase &&
333	<	parentPhase != phase &&
334	<	state == s && casState(s, next)) {
335	<	releaseWaiters(phase);
336	<	if (parties == 0) // exit if the final deregistration
337	<	break;
327	>	int parentPhase = phaseOf(par.getReconciledState());
328	>	if (parentPhase != phase) {
329	>	long next = trippedStateFor(parentPhase, partiesOf(s));
330	>	if (state == s)
331	>	UNSAFE.compareAndSwapLong(this, stateOffset, s, next);
332		}
333		s = state;
334		}
#	Line 348 | Line 342 | public class Phaser {
342		* phaser will need to first register for it.
343		*/
344		public Phaser() {
345	<	this(null);
345	>	this(null, 0);
346		}
347
348		/**
#	Line 372 | Line 366 | public class Phaser {
366		* @param parent the parent phaser
367		*/
368		public Phaser(Phaser parent) {
369	<	int phase = 0;
376	<	this.parent = parent;
377	<	if (parent != null) {
378	<	this.root = parent.root;
379	<	phase = parent.register();
380	<	}
381	<	else
382	<	this.root = this;
383	<	this.state = trippedStateFor(phase, 0);
369	>	this(parent, 0);
370		}
371
372		/**
#	Line 397 | Line 383 | public class Phaser {
383		public Phaser(Phaser parent, int parties) {
384		if (parties < 0 || parties > ushortMask)
385		throw new IllegalArgumentException("Illegal number of parties");
386	<	int phase = 0;
386	>	int phase;
387		this.parent = parent;
388		if (parent != null) {
389	<	this.root = parent.root;
389	>	Phaser r = parent.root;
390	>	this.root = r;
391	>	this.evenQ = r.evenQ;
392	>	this.oddQ = r.oddQ;
393		phase = parent.register();
394		}
395	<	else
395	>	else {
396		this.root = this;
397	+	this.evenQ = new AtomicReference<QNode>();
398	+	this.oddQ = new AtomicReference<QNode>();
399	+	phase = 0;
400	+	}
401		this.state = trippedStateFor(phase, parties);
402		}
403
404		/**
405		* Adds a new unarrived party to this phaser.
406		* If an ongoing invocation of {@link #onAdvance} is in progress,
407	<	* this method waits until its completion before registering.
407	>	* this method may wait until its completion before registering.
408		*
409		* @return the arrival phase number to which this registration applied
410		* @throws IllegalStateException if attempting to register more
#	Line 424 | Line 417 | public class Phaser {
417		/**
418		* Adds the given number of new unarrived parties to this phaser.
419		* If an ongoing invocation of {@link #onAdvance} is in progress,
420	<	* this method waits until its completion before registering.
420	>	* this method may wait until its completion before registering.
421		*
422		* @param parties the number of additional parties required to trip barrier
423		* @return the arrival phase number to which this registration applied
#	Line 452 | Line 445 | public class Phaser {
445		int u = unarrivedOf(s);
446		int unarrived = u + registrations;
447		int parties = p + registrations;
448	<	if (par == null || phase == phaseOf(root.state)) {
449	<	if (parties > ushortMask || unarrived > ushortMask)
450	<	throw new IllegalStateException(badBounds(parties,
451	<	unarrived));
452	<	else if (p != 0 && u == 0)       // back off if advancing
453	<	Thread.yield();              // not worth actually blocking
454	<	else if (casState(s, stateFor(phase, parties, unarrived)))
448	>	if (u == 0 && p != 0)  // if tripped, wait for advance
449	>	untimedWait(phase);
450	>	else if (parties > ushortMask)
451	>	throw new IllegalStateException(badBounds(parties, unarrived));
452	>	else if (par == null || phaseOf(root.state) == phase) {
453	>	long next = stateFor(phase, parties, unarrived);
454	>	if (UNSAFE.compareAndSwapLong(this, stateOffset, s, next))
455		break;
456		}
457		}
#	Line 482 | Line 475 | public class Phaser {
475		while ((phase = phaseOf(s = par==null? state:reconcileState())) >= 0) {
476		int parties = partiesOf(s);
477		int unarrived = unarrivedOf(s) - 1;
478	<	if (parties == 0 || unarrived < 0)
479	<	throw new IllegalStateException(badBounds(parties,
480	<	unarrived));
488	<	else if (unarrived > 0) {           // Not the last arrival
489	<	if (casState(s, s - 1))         // s-1 adds one arrival
490	<	break;
478	>	if (unarrived > 0) {                // Not the last arrival
479	>	if (UNSAFE.compareAndSwapLong(this, stateOffset, s, s - 1))
480	>	break;                      // s-1 adds one arrival
481		}
482	+	else if (unarrived < 0)
483	+	throw new IllegalStateException(badBounds(parties, unarrived));
484		else if (par == null) {             // directly trip
485	<	if (casState(s, trippedStateFor(onAdvance(phase, parties) ? -1 :
486	<	((phase + 1) & phaseMask),
487	<	parties))) {
485	>	long next = trippedStateFor(onAdvance(phase, parties) ? -1 :
486	>	((phase + 1) & phaseMask),
487	>	parties);
488	>	if (UNSAFE.compareAndSwapLong(this, stateOffset, s, next)) {
489		releaseWaiters(phase);
490		break;
491		}
492		}
493	<	else if (phaseOf(root.state) == phase && casState(s, s - 1)) {
493	>	else if (phaseOf(root.state) == phase &&
494	>	UNSAFE.compareAndSwapLong(this, stateOffset, s, s - 1)) {
495		par.arrive();                   // cascade to parent
496		reconcileState();
497		break;
#	Line 527 | Line 521 | public class Phaser {
521		while ((phase = phaseOf(s = par==null? state:reconcileState())) >= 0) {
522		int parties = partiesOf(s) - 1;
523		int unarrived = unarrivedOf(s) - 1;
524	<	if (parties < 0 || unarrived < 0)
525	<	throw new IllegalStateException(badBounds(parties,
526	<	unarrived));
533	<	else if (unarrived > 0) {
534	<	if (casState(s, stateFor(phase, parties, unarrived)))
524	>	if (unarrived > 0) {
525	>	long next = stateFor(phase, parties, unarrived);
526	>	if (UNSAFE.compareAndSwapLong(this, stateOffset, s, next))
527		break;
528		}
529	+	else if (unarrived < 0)
530	+	throw new IllegalStateException(badBounds(parties, unarrived));
531		else if (par == null) {
532	<	if (casState(s, trippedStateFor(onAdvance(phase, parties)? -1:
533	<	(phase + 1) & phaseMask,
534	<	parties))) {
532	>	long next = trippedStateFor(onAdvance(phase, parties)? -1:
533	>	(phase + 1) & phaseMask,
534	>	parties);
535	>	if (UNSAFE.compareAndSwapLong(this, stateOffset, s, next)) {
536		releaseWaiters(phase);
537		break;
538		}
539		}
540	<	else if (phaseOf(root.state) == phase &&
541	<	casState(s, stateFor(phase, parties, 0))) {
542	<	if (parties == 0)
543	<	par.arriveAndDeregister();
544	<	else
545	<	par.arrive();
546	<	reconcileState();
547	<	break;
540	>	else if (phaseOf(root.state) == phase) {
541	>	long next = stateFor(phase, parties, 0);
542	>	if (UNSAFE.compareAndSwapLong(this, stateOffset, s, next)) {
543	>	if (parties == 0)
544	>	par.arriveAndDeregister();
545	>	else
546	>	par.arrive();
547	>	reconcileState();
548	>	break;
549	>	}
550		}
551		}
552		return phase;
#	Line 576 | Line 573 | public class Phaser {
573		* Awaits the phase of the barrier to advance from the given phase
574		* value, returning immediately if the current phase of the
575		* barrier is not equal to the given phase value or this barrier
576	<	* is terminated.  It is an unenforced usage error for an
580	<	* unregistered party to invoke this method.
576	>	* is terminated.
577		*
578		* @param phase an arrival phase number, or negative value if
579		* terminated; this argument is normally the value returned by a
#	Line 599 | Line 595 | public class Phaser {
595		* value, throwing {@code InterruptedException} if interrupted
596		* while waiting, or returning immediately if the current phase of
597		* the barrier is not equal to the given phase value or this
598	<	* barrier is terminated. It is an unenforced usage error for an
603	<	* unregistered party to invoke this method.
598	>	* barrier is terminated.
599		*
600		* @param phase an arrival phase number, or negative value if
601		* terminated; this argument is normally the value returned by a
#	Line 625 | Line 620 | public class Phaser {
620		* InterruptedException} if interrupted while waiting, or
621		* returning immediately if the current phase of the barrier is
622		* not equal to the given phase value or this barrier is
623	<	* terminated.  It is an unenforced usage error for an
629	<	* unregistered party to invoke this method.
623	>	* terminated.
624		*
625		* @param phase an arrival phase number, or negative value if
626		* terminated; this argument is normally the value returned by a
#	Line 663 | Line 657 | public class Phaser {
657		Phaser r = root;    // force at root then reconcile
658		long s;
659		while (phaseOf(s = r.state) >= 0)
660	<	r.casState(s, stateFor(-1, partiesOf(s), unarrivedOf(s)));
660	>	UNSAFE.compareAndSwapLong(r, stateOffset, s,
661	>	stateFor(-1, partiesOf(s),
662	>	unarrivedOf(s)));
663		reconcileState();
664		releaseWaiters(0);  // ensure wakeups on both queues
665		releaseWaiters(1);
#	Line 750 | Line 746 | public class Phaser {
746		* which case no advance occurs.
747		*
748		* <p>The arguments to this method provide the state of the phaser
749	<	* prevailing for the current transition. (When called from within
750	<	* an implementation of {@code onAdvance} the values returned by
751	<	* methods such as {@code getPhase} may or may not reliably
752	<	* indicate the state to which this transition applies.)
749	>	* prevailing for the current transition.  The results and effects
750	>	* of invoking phase-related methods (including {@code getPhase}
751	>	* as well as arrival, registration, and waiting methods) from
752	>	* within {@code onAdvance} are unspecified and should not be
753	>	* relied on. Similarly, while it is possible to override this
754	>	* method to produce side-effects visible to participating tasks,
755	>	* it is in general safe to do so only in designs in which all
756	>	* parties register before any arrive, and all {@link
757	>	* #awaitAdvance} at each phase.
758		*
759		* <p>The default version returns {@code true} when the number of
760		* registered parties is zero. Normally, overrides that arrange
#	Line 879 | Line 880 | public class Phaser {
880		}
881
882		/**
883	+	* The number of times to spin before blocking waiting for advance.
884	+	*/
885	+	static final int MAX_SPINS =
886	+	Runtime.getRuntime().availableProcessors() == 1 ? 0 : 1 << 8;
887	+
888	+	/**
889		* Enqueues node and waits unless aborted or signalled.
890		*
891		* @return current phase
#	Line 887 | Line 894 | public class Phaser {
894		QNode node = null;
895		boolean queued = false;
896		boolean interrupted = false;
897	+	int spins = MAX_SPINS;
898		int p;
899		while ((p = getPhase()) == phase) {
900		if (Thread.interrupted())
901		interrupted = true;
902	+	else if (spins > 0) {
903	+	if (--spins == 0)
904	+	Thread.yield();
905	+	}
906		else if (node == null)
907		node = new QNode(this, phase, false, false, 0, 0);
908		else if (!queued)
#	Line 914 | Line 926 | public class Phaser {
926		QNode node = null;
927		boolean queued = false;
928		boolean interrupted = false;
929	+	int spins = MAX_SPINS;
930		int p;
931		while ((p = getPhase()) == phase && !interrupted) {
932		if (Thread.interrupted())
933		interrupted = true;
934	+	else if (spins > 0) {
935	+	if (--spins == 0)
936	+	Thread.yield();
937	+	}
938		else if (node == null)
939		node = new QNode(this, phase, true, false, 0, 0);
940		else if (!queued)
#	Line 944 | Line 961 | public class Phaser {
961		QNode node = null;
962		boolean queued = false;
963		boolean interrupted = false;
964	+	int spins = MAX_SPINS;
965		int p;
966		while ((p = getPhase()) == phase && !interrupted) {
967		if (Thread.interrupted())
968		interrupted = true;
969		else if (nanos - (System.nanoTime() - startTime) <= 0)
970		break;
971	+	else if (spins > 0) {
972	+	if (--spins == 0)
973	+	Thread.yield();
974	+	}
975		else if (node == null)
976		node = new QNode(this, phase, true, true, startTime, nanos);
977		else if (!queued)
#	Line 974 | Line 996 | public class Phaser {
996		private static final long stateOffset =
997		objectFieldOffset("state", Phaser.class);
998
977	–	private final boolean casState(long cmp, long val) {
978	–	return UNSAFE.compareAndSwapLong(this, stateOffset, cmp, val);
979	–	}
980	–
999		private static long objectFieldOffset(String field, Class<?> klazz) {
1000		try {
1001		return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));

Diff Legend

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