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 1.2 by jsr166, Fri Jul 25 18:10:41 2008 UTC vs.
Revision 1.12 by jsr166, Thu Mar 19 05:10:42 2009 UTC

#	Line 5 | Line 5
5		*/
6
7		package jsr166y;
8	<	import jsr166y.forkjoin.*;
8	>
9		import java.util.concurrent.*;
10		import java.util.concurrent.atomic.*;
11		import java.util.concurrent.locks.LockSupport;
12	+	import sun.misc.Unsafe;
13	+	import java.lang.reflect.*;
14
15		/**
16		* A reusable synchronization barrier, similar in functionality to a
17	<	* {@link java.util.concurrent.CyclicBarrier}, but supporting more
18	<	* flexible usage.
17	>	* {@link java.util.concurrent.CyclicBarrier CyclicBarrier} and
18	>	* {@link java.util.concurrent.CountDownLatch CountDownLatch}
19	>	* but supporting more flexible usage.
20		*
21		* <ul>
22		*
23	<	* <li> The number of parties synchronizing on the barrier may vary
24	<	* over time.  A task may register to be a party in a barrier at any
25	<	* time, and may deregister upon arriving at the barrier.  As is the
26	<	* case with most basic synchronization constructs, registration
27	<	* and deregistration affect only internal counts; they do not
28	<	* establish any further internal bookkeeping, so tasks cannot query
29	<	* whether they are registered.
23	>	* <li> The number of parties synchronizing on a phaser may vary over
24	>	* time.  A task may register to be a party at any time, and may
25	>	* deregister upon arriving at the barrier.  As is the case with most
26	>	* basic synchronization constructs, registration and deregistration
27	>	* affect only internal counts; they do not establish any further
28	>	* internal bookkeeping, so tasks cannot query whether they are
29	>	* registered. (However, you can introduce such bookkeeping by
30	>	* subclassing this class.)
31		*
32		* <li> Each generation has an associated phase value, starting at
33		* zero, and advancing when all parties reach the barrier (wrapping
34	<	* around to zero after reaching <tt>Integer.MAX_VALUE</tt>).
35	<	*
34	>	* around to zero after reaching {@code Integer.MAX_VALUE}).
35	>	*
36		* <li> Like a CyclicBarrier, a Phaser may be repeatedly awaited.
37	<	* Method <tt>arriveAndAwaitAdvance</tt> has effect analogous to
38	<	* <tt>CyclicBarrier.await</tt>.  However, Phasers separate two
39	<	* aspects of coordination, that may be invoked independently:
37	>	* Method {@code arriveAndAwaitAdvance} has effect analogous to
38	>	* {@code CyclicBarrier.await}.  However, Phasers separate two
39	>	* aspects of coordination, that may also be invoked independently:
40		*
41		* <ul>
42		*
43	<	*   <li> Arriving at a barrier. Methods <tt>arrive</tt> and
44	<	*       <tt>arriveAndDeregister</tt> do not block, but return
45	<	*       the phase value on entry to the method.
43	>	*   <li> Arriving at a barrier. Methods {@code arrive} and
44	>	*       {@code arriveAndDeregister} do not block, but return
45	>	*       the phase value current upon entry to the method.
46		*
47	<	*   <li> Awaiting others. Method <tt>awaitAdvance</tt> requires an
47	>	*   <li> Awaiting others. Method {@code awaitAdvance} requires an
48		*       argument indicating the entry phase, and returns when the
49		*       barrier advances to a new phase.
50		* </ul>
#	Line 48 | Line 52 | import java.util.concurrent.locks.LockSu
52		*
53		* <li> Barrier actions, performed by the task triggering a phase
54		* advance while others may be waiting, are arranged by overriding
55	<	* method <tt>onAdvance</tt>, that also controls termination.
55	>	* method {@code onAdvance}, that also controls termination.
56	>	* Overriding this method may be used to similar but more flexible
57	>	* effect as providing a barrier action to a CyclicBarrier.
58		*
59		* <li> Phasers may enter a <em>termination</em> state in which all
60	<	* await actions immediately return, indicating (via a negative phase
61	<	* value) that execution is complete.  Termination is triggered by
62	<	* executing the overridable <tt>onAdvance</tt> method that is invoked
63	<	* each time the barrier is tripped. When a Phaser is controlling an
60	>	* actions immediately return without updating phaser state or waiting
61	>	* for advance, and indicating (via a negative phase value) that
62	>	* execution is complete.  Termination is triggered by executing the
63	>	* overridable {@code onAdvance} method that is invoked each time the
64	>	* barrier is about to be tripped. When a Phaser is controlling an
65		* action with a fixed number of iterations, it is often convenient to
66		* override this method to cause termination when the current phase
67	<	* number reaches a threshold.  Method <tt>forceTermination</tt> is
68	<	* also available to assist recovery actions upon failure.
67	>	* number reaches a threshold. Method {@code forceTermination} is also
68	>	* available to abruptly release waiting threads and allow them to
69	>	* terminate.
70	>	*
71	>	* <li> Phasers may be tiered to reduce contention. Phasers with large
72	>	* numbers of parties that would otherwise experience heavy
73	>	* synchronization contention costs may instead be arranged in trees.
74	>	* This will typically greatly increase throughput even though it
75	>	* incurs somewhat greater per-operation overhead.
76		*
77	<	* <li> Unlike most synchronizers, a Phaser may also be used with
78	<	* ForkJoinTasks (as well as plain threads).
65	<	*
66	<	* <li> By default, <tt>awaitAdvance</tt> continues to wait even if
67	<	* the current thread is interrupted. And unlike the case in
77	>	* <li> By default, {@code awaitAdvance} continues to wait even if
78	>	* the waiting thread is interrupted. And unlike the case in
79		* CyclicBarriers, exceptions encountered while tasks wait
80		* interruptibly or with timeout do not change the state of the
81		* barrier. If necessary, you can perform any associated recovery
82	<	* within handlers of those exceptions.
82	>	* within handlers of those exceptions, often after invoking
83	>	* {@code forceTermination}.
84		*
85	<	* </ul>
85	>	* <li>Phasers ensure lack of starvation when used by ForkJoinTasks.
86		*
87	<	* <p><b>Sample usage:</b>
87	>	* </ul>
88		*
89	<	* <p>[todo: non-FJ example]
89	>	* <p><b>Sample usages:</b>
90		*
91	<	* <p> A Phaser may be used to support a style of programming in
92	<	* which a task waits for others to complete, without otherwise
93	<	* needing to keep track of which tasks it is waiting for. This is
94	<	* similar to the "sync" construct in Cilk and "clocks" in X10.
83	<	* Special constructions based on such barriers are available using
84	<	* the <tt>LinkedAsyncAction</tt> and <tt>CyclicAction</tt> classes,
85	<	* but they can be useful in other contexts as well.  For a simple
86	<	* (but not very useful) example, here is a variant of Fibonacci:
91	>	* <p>A Phaser may be used instead of a {@code CountDownLatch} to control
92	>	* a one-shot action serving a variable number of parties. The typical
93	>	* idiom is for the method setting this up to first register, then
94	>	* start the actions, then deregister, as in:
95		*
96		* <pre>
97	<	* class BarrierFibonacci extends RecursiveAction {
98	<	*   int argument, result;
99	<	*   final Phaser parentBarrier;
100	<	*   BarrierFibonacci(int n, Phaser parentBarrier) {
101	<	*     this.argument = n;
102	<	*     this.parentBarrier = parentBarrier;
103	<	*     parentBarrier.register();
97	>	*  void runTasks(List&lt;Runnable&gt; list) {
98	>	*    final Phaser phaser = new Phaser(1); // "1" to register self
99	>	*    for (Runnable r : list) {
100	>	*      phaser.register();
101	>	*      new Thread() {
102	>	*        public void run() {
103	>	*          phaser.arriveAndAwaitAdvance(); // await all creation
104	>	*          r.run();
105	>	*          phaser.arriveAndDeregister();   // signal completion
106	>	*        }
107	>	*      }.start();
108		*   }
109	<	*   protected void compute() {
110	<	*     int n = argument;
111	<	*     if (n &lt;= 1)
112	<	*        result = n;
113	<	*     else {
114	<	*        Phaser childBarrier = new Phaser(1);
115	<	*        BarrierFibonacci f1 = new BarrierFibonacci(n - 1, childBarrier);
116	<	*        BarrierFibonacci f2 = new BarrierFibonacci(n - 2, childBarrier);
117	<	*        f1.fork();
118	<	*        f2.fork();
119	<	*        childBarrier.arriveAndAwait();
120	<	*        result = f1.result + f2.result;
121	<	*     }
122	<	*     parentBarrier.arriveAndDeregister();
109	>	*
110	>	*   doSomethingOnBehalfOfWorkers();
111	>	*   phaser.arrive(); // allow threads to start
112	>	*   int p = phaser.arriveAndDeregister(); // deregister self  ...
113	>	*   p = phaser.awaitAdvance(p); // ... and await arrival
114	>	*   otherActions(); // do other things while tasks execute
115	>	*   phaser.awaitAdvance(p); // await final completion
116	>	* }
117	>	* </pre>
118	>	*
119	>	* <p>One way to cause a set of threads to repeatedly perform actions
120	>	* for a given number of iterations is to override {@code onAdvance}:
121	>	*
122	>	* <pre>
123	>	*  void startTasks(List&lt;Runnable&gt; list, final int iterations) {
124	>	*    final Phaser phaser = new Phaser() {
125	>	*       public boolean onAdvance(int phase, int registeredParties) {
126	>	*         return phase &gt;= iterations || registeredParties == 0;
127	>	*       }
128	>	*    };
129	>	*    phaser.register();
130	>	*    for (Runnable r : list) {
131	>	*      phaser.register();
132	>	*      new Thread() {
133	>	*        public void run() {
134	>	*           do {
135	>	*             r.run();
136	>	*             phaser.arriveAndAwaitAdvance();
137	>	*           } while(!phaser.isTerminated();
138	>	*        }
139	>	*      }.start();
140		*   }
141	+	*   phaser.arriveAndDeregister(); // deregister self, don't wait
142		* }
143		* </pre>
144		*
145	+	* <p> To create a set of tasks using a tree of Phasers,
146	+	* you could use code of the following form, assuming a
147	+	* Task class with a constructor accepting a Phaser that
148	+	* it registers for upon construction:
149	+	* <pre>
150	+	*  void build(Task[] actions, int lo, int hi, Phaser b) {
151	+	*    int step = (hi - lo) / TASKS_PER_PHASER;
152	+	*    if (step &gt; 1) {
153	+	*       int i = lo;
154	+	*       while (i &lt; hi) {
155	+	*         int r = Math.min(i + step, hi);
156	+	*         build(actions, i, r, new Phaser(b));
157	+	*         i = r;
158	+	*       }
159	+	*    }
160	+	*    else {
161	+	*      for (int i = lo; i &lt; hi; ++i)
162	+	*        actions[i] = new Task(b);
163	+	*        // assumes new Task(b) performs b.register()
164	+	*    }
165	+	*  }
166	+	*  // .. initially called, for n tasks via
167	+	*  build(new Task[n], 0, n, new Phaser());
168	+	* </pre>
169	+	*
170	+	* The best value of {@code TASKS_PER_PHASER} depends mainly on
171	+	* expected barrier synchronization rates. A value as low as four may
172	+	* be appropriate for extremely small per-barrier task bodies (thus
173	+	* high rates), or up to hundreds for extremely large ones.
174	+	*
175	+	* </pre>
176	+	*
177		* <p><b>Implementation notes</b>: This implementation restricts the
178	<	* maximum number of parties to 65535. Attempts to register
179	<	* additional parties result in IllegalStateExceptions.
178	>	* maximum number of parties to 65535. Attempts to register additional
179	>	* parties result in IllegalStateExceptions. However, you can and
180	>	* should create tiered phasers to accommodate arbitrarily large sets
181	>	* of participants.
182		*/
183		public class Phaser {
184		/*
185		* This class implements an extension of X10 "clocks".  Thanks to
186	<	* Vijay Saraswat for the idea of applying it to ForkJoinTasks,
187	<	* and to Vivek Sarkar for enhancements to extend functionality.
186	>	* Vijay Saraswat for the idea, and to Vivek Sarkar for
187	>	* enhancements to extend functionality.
188		*/
189
190		/**
191		* Barrier state representation. Conceptually, a barrier contains
192		* four values:
193	<	*
193	>	*
194		* * parties -- the number of parties to wait (16 bits)
195		* * unarrived -- the number of parties yet to hit barrier (16 bits)
196		* * phase -- the generation of the barrier (31 bits)
197		* * terminated -- set if barrier is terminated (1 bit)
198		*
199		* However, to efficiently maintain atomicity, these values are
200	<	* packed into a single AtomicLong. Termination uses the sign bit
201	<	* of 32 bit representation of phase, so phase is set to -1 on
202	<	* termination.
203	<	*/
204	<	private final AtomicLong state;
205	<
206	<	/**
143	<	* Head of Treiber stack for waiting nonFJ threads.
200	>	* packed into a single (atomic) long. Termination uses the sign
201	>	* bit of 32 bit representation of phase, so phase is set to -1 on
202	>	* termination. Good performance relies on keeping state decoding
203	>	* and encoding simple, and keeping race windows short.
204	>	*
205	>	* Note: there are some cheats in arrive() that rely on unarrived
206	>	* count being lowest 16 bits.
207		*/
208	<	private final AtomicReference<QNode> head = new AtomicReference<QNode>();
208	>	private volatile long state;
209
210		private static final int ushortBits = 16;
211	<	private static final int ushortMask =  (1 << ushortBits) - 1;
212	<	private static final int phaseMask = 0x7fffffff;
211	>	private static final int ushortMask = 0xffff;
212	>	private static final int phaseMask  = 0x7fffffff;
213
214		private static int unarrivedOf(long s) {
215		return (int)(s & ushortMask);
216		}
217
218		private static int partiesOf(long s) {
219	<	return (int)(s & (ushortMask << 16)) >>> 16;
219	>	return ((int)s) >>> 16;
220		}
221
222		private static int phaseOf(long s) {
#	Line 165 | Line 228 | public class Phaser {
228		}
229
230		private static long stateFor(int phase, int parties, int unarrived) {
231	<	return (((long)phase) << 32) | ((parties << 16) | unarrived);
231	>	return ((((long)phase) << 32) | (((long)parties) << 16) |
232	>	(long)unarrived);
233	>	}
234	>
235	>	private static long trippedStateFor(int phase, int parties) {
236	>	long lp = (long)parties;
237	>	return (((long)phase) << 32) | (lp << 16) | lp;
238	>	}
239	>
240	>	/**
241	>	* Returns message string for bad bounds exceptions
242	>	*/
243	>	private static String badBounds(int parties, int unarrived) {
244	>	return ("Attempt to set " + unarrived +
245	>	" unarrived of " + parties + " parties");
246	>	}
247	>
248	>	/**
249	>	* The parent of this phaser, or null if none
250	>	*/
251	>	private final Phaser parent;
252	>
253	>	/**
254	>	* The root of Phaser tree. Equals this if not in a tree.  Used to
255	>	* support faster state push-down.
256	>	*/
257	>	private final Phaser root;
258	>
259	>	// Wait queues
260	>
261	>	/**
262	>	* Heads of Treiber stacks for waiting threads. To eliminate
263	>	* contention while releasing some threads while adding others, we
264	>	* use two of them, alternating across even and odd phases.
265	>	*/
266	>	private final AtomicReference<QNode> evenQ = new AtomicReference<QNode>();
267	>	private final AtomicReference<QNode> oddQ  = new AtomicReference<QNode>();
268	>
269	>	private AtomicReference<QNode> queueFor(int phase) {
270	>	return (phase & 1) == 0? evenQ : oddQ;
271		}
272
273	<	private static IllegalStateException badBounds(int parties, int unarrived) {
274	<	return new IllegalStateException("Attempt to set " + unarrived +
275	<	" unarrived of " + parties + " parties");
273	>	/**
274	>	* Returns current state, first resolving lagged propagation from
275	>	* root if necessary.
276	>	*/
277	>	private long getReconciledState() {
278	>	return parent == null? state : reconcileState();
279	>	}
280	>
281	>	/**
282	>	* Recursively resolves state.
283	>	*/
284	>	private long reconcileState() {
285	>	Phaser p = parent;
286	>	long s = state;
287	>	if (p != null) {
288	>	while (unarrivedOf(s) == 0 && phaseOf(s) != phaseOf(root.state)) {
289	>	long parentState = p.getReconciledState();
290	>	int parentPhase = phaseOf(parentState);
291	>	int phase = phaseOf(s = state);
292	>	if (phase != parentPhase) {
293	>	long next = trippedStateFor(parentPhase, partiesOf(s));
294	>	if (casState(s, next)) {
295	>	releaseWaiters(phase);
296	>	s = next;
297	>	}
298	>	}
299	>	}
300	>	}
301	>	return s;
302		}
303
304		/**
305		* Creates a new Phaser without any initially registered parties,
306	<	* and initial phase number 0.
306	>	* initial phase number 0, and no parent. Any thread using this
307	>	* Phaser will need to first register for it.
308		*/
309		public Phaser() {
310	<	state = new AtomicLong(stateFor(0, 0, 0));
310	>	this(null);
311		}
312
313		/**
314		* Creates a new Phaser with the given numbers of registered
315	<	* unarrived parties and initial phase number 0.
315	>	* unarrived parties, initial phase number 0, and no parent.
316		* @param parties the number of parties required to trip barrier.
317		* @throws IllegalArgumentException if parties less than zero
318		* or greater than the maximum number of parties supported.
319		*/
320		public Phaser(int parties) {
321	+	this(null, parties);
322	+	}
323	+
324	+	/**
325	+	* Creates a new Phaser with the given parent, without any
326	+	* initially registered parties. If parent is non-null this phaser
327	+	* is registered with the parent and its initial phase number is
328	+	* the same as that of parent phaser.
329	+	* @param parent the parent phaser.
330	+	*/
331	+	public Phaser(Phaser parent) {
332	+	int phase = 0;
333	+	this.parent = parent;
334	+	if (parent != null) {
335	+	this.root = parent.root;
336	+	phase = parent.register();
337	+	}
338	+	else
339	+	this.root = this;
340	+	this.state = trippedStateFor(phase, 0);
341	+	}
342	+
343	+	/**
344	+	* Creates a new Phaser with the given parent and numbers of
345	+	* registered unarrived parties. If parent is non-null this phaser
346	+	* is registered with the parent and its initial phase number is
347	+	* the same as that of parent phaser.
348	+	* @param parent the parent phaser.
349	+	* @param parties the number of parties required to trip barrier.
350	+	* @throws IllegalArgumentException if parties less than zero
351	+	* or greater than the maximum number of parties supported.
352	+	*/
353	+	public Phaser(Phaser parent, int parties) {
354		if (parties < 0 || parties > ushortMask)
355		throw new IllegalArgumentException("Illegal number of parties");
356	<	state = new AtomicLong(stateFor(0, parties, parties));
356	>	int phase = 0;
357	>	this.parent = parent;
358	>	if (parent != null) {
359	>	this.root = parent.root;
360	>	phase = parent.register();
361	>	}
362	>	else
363	>	this.root = this;
364	>	this.state = trippedStateFor(phase, parties);
365		}
366
367		/**
#	Line 200 | Line 370 | public class Phaser {
370		* @throws IllegalStateException if attempting to register more
371		* than the maximum supported number of parties.
372		*/
373	<	public int register() { // increment both parties and unarrived
374	<	final AtomicLong state = this.state;
373	>	public int register() {
374	>	return doRegister(1);
375	>	}
376	>
377	>	/**
378	>	* Adds the given number of new unarrived parties to this phaser.
379	>	* @param parties the number of parties required to trip barrier.
380	>	* @return the current barrier phase number upon registration
381	>	* @throws IllegalStateException if attempting to register more
382	>	* than the maximum supported number of parties.
383	>	*/
384	>	public int bulkRegister(int parties) {
385	>	if (parties < 0)
386	>	throw new IllegalArgumentException();
387	>	if (parties == 0)
388	>	return getPhase();
389	>	return doRegister(parties);
390	>	}
391	>
392	>	/**
393	>	* Shared code for register, bulkRegister
394	>	*/
395	>	private int doRegister(int registrations) {
396	>	int phase;
397		for (;;) {
398	<	long s = state.get();
399	<	int phase = phaseOf(s);
400	<	int parties = partiesOf(s) + 1;
401	<	int unarrived = unarrivedOf(s) + 1;
398	>	long s = getReconciledState();
399	>	phase = phaseOf(s);
400	>	int unarrived = unarrivedOf(s) + registrations;
401	>	int parties = partiesOf(s) + registrations;
402	>	if (phase < 0)
403	>	break;
404		if (parties > ushortMask || unarrived > ushortMask)
405	<	throw badBounds(parties, unarrived);
406	<	if (state.compareAndSet(s, stateFor(phase, parties, unarrived)))
407	<	return phase;
405	>	throw new IllegalStateException(badBounds(parties, unarrived));
406	>	if (phase == phaseOf(root.state) &&
407	>	casState(s, stateFor(phase, parties, unarrived)))
408	>	break;
409		}
410	+	return phase;
411		}
412
413		/**
414		* Arrives at the barrier, but does not wait for others.  (You can
415		* in turn wait for others via {@link #awaitAdvance}).
416		*
417	<	* @return the current barrier phase number upon entry to
418	<	* this method, or a negative value if terminated;
419	<	* @throws IllegalStateException if the number of unarrived
420	<	* parties would become negative.
417	>	* @return the barrier phase number upon entry to this method, or a
418	>	* negative value if terminated;
419	>	* @throws IllegalStateException if not terminated and the number
420	>	* of unarrived parties would become negative.
421		*/
422	<	public int arrive() { // decrement unarrived. If zero, trip
423	<	final AtomicLong state = this.state;
422	>	public int arrive() {
423	>	int phase;
424		for (;;) {
425	<	long s = state.get();
426	<	int phase = phaseOf(s);
425	>	long s = state;
426	>	phase = phaseOf(s);
427	>	if (phase < 0)
428	>	break;
429		int parties = partiesOf(s);
430		int unarrived = unarrivedOf(s) - 1;
431	<	if (unarrived < 0)
432	<	throw badBounds(parties, unarrived);
433	<	if (unarrived == 0 && phase >= 0) {
434	<	trip(phase, parties);
435	<	return phase;
431	>	if (unarrived > 0) {        // Not the last arrival
432	>	if (casState(s, s - 1)) // s-1 adds one arrival
433	>	break;
434	>	}
435	>	else if (unarrived == 0) {  // the last arrival
436	>	Phaser par = parent;
437	>	if (par == null) {      // directly trip
438	>	if (casState
439	>	(s,
440	>	trippedStateFor(onAdvance(phase, parties)? -1 :
441	>	((phase + 1) & phaseMask), parties))) {
442	>	releaseWaiters(phase);
443	>	break;
444	>	}
445	>	}
446	>	else {                  // cascade to parent
447	>	if (casState(s, s - 1)) { // zeroes unarrived
448	>	par.arrive();
449	>	reconcileState();
450	>	break;
451	>	}
452	>	}
453		}
454	<	if (state.compareAndSet(s, stateFor(phase, parties, unarrived)))
455	<	return phase;
454	>	else if (phase != phaseOf(root.state)) // or if unreconciled
455	>	reconcileState();
456	>	else
457	>	throw new IllegalStateException(badBounds(parties, unarrived));
458		}
459	+	return phase;
460		}
461
462		/**
463		* Arrives at the barrier, and deregisters from it, without
464	<	* waiting for others.
464	>	* waiting for others. Deregistration reduces number of parties
465	>	* required to trip the barrier in future phases.  If this phaser
466	>	* has a parent, and deregistration causes this phaser to have
467	>	* zero parties, this phaser is also deregistered from its parent.
468		*
469		* @return the current barrier phase number upon entry to
470		* this method, or a negative value if terminated;
471	<	* @throws IllegalStateException if the number of registered or
472	<	* unarrived parties would become negative.
471	>	* @throws IllegalStateException if not terminated and the number
472	>	* of registered or unarrived parties would become negative.
473		*/
474	<	public int arriveAndDeregister() { // Same as arrive, plus decrement parties
475	<	final AtomicLong state = this.state;
474	>	public int arriveAndDeregister() {
475	>	// similar code to arrive, but too different to merge
476	>	Phaser par = parent;
477	>	int phase;
478		for (;;) {
479	<	long s = state.get();
480	<	int phase = phaseOf(s);
479	>	long s = state;
480	>	phase = phaseOf(s);
481	>	if (phase < 0)
482	>	break;
483		int parties = partiesOf(s) - 1;
484		int unarrived = unarrivedOf(s) - 1;
485	<	if (parties < 0 || unarrived < 0)
486	<	throw badBounds(parties, unarrived);
487	<	if (unarrived == 0 && phase >= 0) {
488	<	trip(phase, parties);
489	<	return phase;
485	>	if (parties >= 0) {
486	>	if (unarrived > 0 || (unarrived == 0 && par != null)) {
487	>	if (casState
488	>	(s,
489	>	stateFor(phase, parties, unarrived))) {
490	>	if (unarrived == 0) {
491	>	par.arriveAndDeregister();
492	>	reconcileState();
493	>	}
494	>	break;
495	>	}
496	>	continue;
497	>	}
498	>	if (unarrived == 0) {
499	>	if (casState
500	>	(s,
501	>	trippedStateFor(onAdvance(phase, parties)? -1 :
502	>	((phase + 1) & phaseMask), parties))) {
503	>	releaseWaiters(phase);
504	>	break;
505	>	}
506	>	continue;
507	>	}
508	>	if (par != null && phase != phaseOf(root.state)) {
509	>	reconcileState();
510	>	continue;
511	>	}
512		}
513	<	if (state.compareAndSet(s, stateFor(phase, parties, unarrived)))
267	<	return phase;
513	>	throw new IllegalStateException(badBounds(parties, unarrived));
514		}
515	+	return phase;
516		}
517
518		/**
519	<	* Arrives at the barrier and awaits others. Unlike other arrival
520	<	* methods, this method returns the arrival index of the
521	<	* caller. The caller tripping the barrier returns zero, the
522	<	* previous caller 1, and so on.
523	<	* @return the arrival index
524	<	* @throws IllegalStateException if the number of unarrived
525	<	* parties would become negative.
519	>	* Arrives at the barrier and awaits others. Equivalent in effect
520	>	* to {@code awaitAdvance(arrive())}.  If you instead need to
521	>	* await with interruption of timeout, and/or deregister upon
522	>	* arrival, you can arrange them using analogous constructions.
523	>	* @return the phase on entry to this method
524	>	* @throws IllegalStateException if not terminated and the number
525	>	* of unarrived parties would become negative.
526		*/
527		public int arriveAndAwaitAdvance() {
528	<	final AtomicLong state = this.state;
282	<	for (;;) {
283	<	long s = state.get();
284	<	int phase = phaseOf(s);
285	<	int parties = partiesOf(s);
286	<	int unarrived = unarrivedOf(s) - 1;
287	<	if (unarrived < 0)
288	<	throw badBounds(parties, unarrived);
289	<	if (unarrived == 0 && phase >= 0) {
290	<	trip(phase, parties);
291	<	return 0;
292	<	}
293	<	if (state.compareAndSet(s, stateFor(phase, parties, unarrived))) {
294	<	awaitAdvance(phase);
295	<	return unarrived;
296	<	}
297	<	}
528	>	return awaitAdvance(arrive());
529		}
530
531		/**
532		* Awaits the phase of the barrier to advance from the given
533	<	* value, or returns immediately if this barrier is terminated.
533	>	* value, or returns immediately if argument is negative or this
534	>	* barrier is terminated.
535		* @param phase the phase on entry to this method
536		* @return the phase on exit from this method
537		*/
538		public int awaitAdvance(int phase) {
539		if (phase < 0)
540		return phase;
541	<	Thread current = Thread.currentThread();
542	<	if (current instanceof ForkJoinWorkerThread)
543	<	return helpingWait(phase);
544	<	if (untimedWait(current, phase, false))
545	<	current.interrupt();
546	<	return phaseOf(state.get());
541	>	long s = getReconciledState();
542	>	int p = phaseOf(s);
543	>	if (p != phase)
544	>	return p;
545	>	if (unarrivedOf(s) == 0 && parent != null)
546	>	parent.awaitAdvance(phase);
547	>	// Fall here even if parent waited, to reconcile and help release
548	>	return untimedWait(phase);
549		}
550
551		/**
552		* Awaits the phase of the barrier to advance from the given
553	<	* value, or returns immediately if this barrier is terminated, or
554	<	* throws InterruptedException if interrupted while waiting.
553	>	* value, or returns immediately if argument is negative or this
554	>	* barrier is terminated, or throws InterruptedException if
555	>	* interrupted while waiting.
556		* @param phase the phase on entry to this method
557		* @return the phase on exit from this method
558		* @throws InterruptedException if thread interrupted while waiting
559		*/
560	<	public int awaitAdvanceInterruptibly(int phase) throws InterruptedException {
560	>	public int awaitAdvanceInterruptibly(int phase)
561	>	throws InterruptedException {
562		if (phase < 0)
563		return phase;
564	<	Thread current = Thread.currentThread();
565	<	if (current instanceof ForkJoinWorkerThread)
566	<	return helpingWait(phase);
567	<	else if (Thread.interrupted() || untimedWait(current, phase, true))
568	<	throw new InterruptedException();
569	<	else
570	<	return phaseOf(state.get());
564	>	long s = getReconciledState();
565	>	int p = phaseOf(s);
566	>	if (p != phase)
567	>	return p;
568	>	if (unarrivedOf(s) == 0 && parent != null)
569	>	parent.awaitAdvanceInterruptibly(phase);
570	>	return interruptibleWait(phase);
571		}
572
573		/**
574		* Awaits the phase of the barrier to advance from the given value
575	<	* or the given timeout elapses, or returns immediately if this
576	<	* barrier is terminated.
575	>	* or the given timeout elapses, or returns immediately if
576	>	* argument is negative or this barrier is terminated.
577		* @param phase the phase on entry to this method
578		* @return the phase on exit from this method
579		* @throws InterruptedException if thread interrupted while waiting
580		* @throws TimeoutException if timed out while waiting
581		*/
582	<	public int awaitAdvanceInterruptibly(int phase, long timeout, TimeUnit unit)
582	>	public int awaitAdvanceInterruptibly(int phase, long timeout, TimeUnit unit)
583		throws InterruptedException, TimeoutException {
584		if (phase < 0)
585		return phase;
586	<	long nanos = unit.toNanos(timeout);
587	<	Thread current = Thread.currentThread();
588	<	if (current instanceof ForkJoinWorkerThread)
589	<	return timedHelpingWait(phase, nanos);
590	<	timedWait(current, phase, nanos);
591	<	return phaseOf(state.get());
586	>	long s = getReconciledState();
587	>	int p = phaseOf(s);
588	>	if (p != phase)
589	>	return p;
590	>	if (unarrivedOf(s) == 0 && parent != null)
591	>	parent.awaitAdvanceInterruptibly(phase, timeout, unit);
592	>	return timedWait(phase, unit.toNanos(timeout));
593		}
594
595		/**
596		* Forces this barrier to enter termination state. Counts of
597	<	* arrived and registered parties are unaffected. This method may
598	<	* be useful for coordinating recovery after one or more tasks
599	<	* encounter unexpected exceptions.
597	>	* arrived and registered parties are unaffected. If this phaser
598	>	* has a parent, it too is terminated. This method may be useful
599	>	* for coordinating recovery after one or more tasks encounter
600	>	* unexpected exceptions.
601		*/
602		public void forceTermination() {
365	–	final AtomicLong state = this.state;
603		for (;;) {
604	<	long s = state.get();
604	>	long s = getReconciledState();
605		int phase = phaseOf(s);
606		int parties = partiesOf(s);
607		int unarrived = unarrivedOf(s);
608		if (phase < 0 ||
609	<	state.compareAndSet(s, stateFor(-1, parties, unarrived))) {
610	<	if (head.get() != null)
611	<	releaseWaiters(-1);
609	>	casState(s, stateFor(-1, parties, unarrived))) {
610	>	releaseWaiters(0);
611	>	releaseWaiters(1);
612	>	if (parent != null)
613	>	parent.forceTermination();
614		return;
615		}
616		}
617		}
618
619		/**
620	<	* Resets the barrier with the given numbers of registered unarrived
621	<	* parties and phase number 0. This method allows repeated reuse
622	<	* of this barrier, but only if it is somehow known not to be in
623	<	* use for other purposes.
385	<	* @param parties the number of parties required to trip barrier.
386	<	* @throws IllegalArgumentException if parties less than zero
387	<	* or greater than the maximum number of parties supported.
620	>	* Returns the current phase number. The maximum phase number is
621	>	* {@code Integer.MAX_VALUE}, after which it restarts at
622	>	* zero. Upon termination, the phase number is negative.
623	>	* @return the phase number, or a negative value if terminated
624		*/
625	<	public void reset(int parties) {
626	<	if (parties < 0 || parties > ushortMask)
391	<	throw new IllegalArgumentException("Illegal number of parties");
392	<	state.set(stateFor(0, parties, parties));
393	<	if (head.get() != null)
394	<	releaseWaiters(0);
625	>	public final int getPhase() {
626	>	return phaseOf(getReconciledState());
627		}
628
629		/**
630	<	* Returns the current phase number. The maximum phase number is
631	<	* <tt>Integer.MAX_VALUE</tt>, after which it restarts at
632	<	* zero. Upon termination, the phase number is negative.
401	<	* @return the phase number, or a negative value if terminated
630	>	* Returns {@code true} if the current phase number equals the given phase.
631	>	* @param phase the phase
632	>	* @return {@code true} if the current phase number equals the given phase
633		*/
634	<	public int getPhase() {
635	<	return phaseOf(state.get());
634	>	public final boolean hasPhase(int phase) {
635	>	return phaseOf(getReconciledState()) == phase;
636		}
637
638		/**
#	Line 409 | Line 640 | public class Phaser {
640		* @return the number of parties
641		*/
642		public int getRegisteredParties() {
643	<	return partiesOf(state.get());
643	>	return partiesOf(state);
644		}
645
646		/**
#	Line 418 | Line 649 | public class Phaser {
649		* @return the number of arrived parties
650		*/
651		public int getArrivedParties() {
652	<	return arrivedOf(state.get());
652	>	return arrivedOf(state);
653		}
654
655		/**
#	Line 427 | Line 658 | public class Phaser {
658		* @return the number of unarrived parties
659		*/
660		public int getUnarrivedParties() {
661	<	return unarrivedOf(state.get());
661	>	return unarrivedOf(state);
662	>	}
663	>
664	>	/**
665	>	* Returns the parent of this phaser, or null if none.
666	>	* @return the parent of this phaser, or null if none
667	>	*/
668	>	public Phaser getParent() {
669	>	return parent;
670		}
671
672		/**
673	<	* Returns true if this barrier has been terminated.
674	<	* @return true if this barrier has been terminated
673	>	* Returns the root ancestor of this phaser, which is the same as
674	>	* this phaser if it has no parent.
675	>	* @return the root ancestor of this phaser
676	>	*/
677	>	public Phaser getRoot() {
678	>	return root;
679	>	}
680	>
681	>	/**
682	>	* Returns {@code true} if this barrier has been terminated.
683	>	* @return {@code true} if this barrier has been terminated
684		*/
685		public boolean isTerminated() {
686	<	return phaseOf(state.get()) < 0;
686	>	return getPhase() < 0;
687		}
688
689		/**
#	Line 444 | Line 692 | public class Phaser {
692		* barrier is tripped (and thus all other waiting parties are
693		* dormant). If it returns true, then, rather than advance the
694		* phase number, this barrier will be set to a final termination
695	<	* state, and subsequent calls to <tt>isTerminated</tt> will
695	>	* state, and subsequent calls to {@code isTerminated} will
696		* return true.
697	<	*
697	>	*
698		* <p> The default version returns true when the number of
699		* registered parties is zero. Normally, overrides that arrange
700		* termination for other reasons should also preserve this
701		* property.
702		*
703	+	* <p> You may override this method to perform an action with side
704	+	* effects visible to participating tasks, but it is in general
705	+	* only sensible to do so in designs where all parties register
706	+	* before any arrive, and all {@code awaitAdvance} at each phase.
707	+	* Otherwise, you cannot ensure lack of interference. In
708	+	* particular, this method may be invoked more than once per
709	+	* transition if other parties successfully register while the
710	+	* invocation of this method is in progress, thus postponing the
711	+	* transition until those parties also arrive, re-triggering this
712	+	* method.
713	+	*
714		* @param phase the phase number on entering the barrier
715	<	* @param registeredParties the current number of registered
716	<	* parties.
458	<	* @return true if this barrier should terminate
715	>	* @param registeredParties the current number of registered parties
716	>	* @return {@code true} if this barrier should terminate
717		*/
718		protected boolean onAdvance(int phase, int registeredParties) {
719		return registeredParties <= 0;
720		}
721
722		/**
723	<	* Returns a string identifying this barrier, as well as its
723	>	* Returns a string identifying this phaser, as well as its
724		* state.  The state, in brackets, includes the String {@code
725	<	* "phase ="} followed by the phase number, {@code "parties ="}
725	>	* "phase = "} followed by the phase number, {@code "parties = "}
726		* followed by the number of registered parties, and {@code
727	<	* "arrived ="} followed by the number of arrived parties
727	>	* "arrived = "} followed by the number of arrived parties.
728		*
729		* @return a string identifying this barrier, as well as its state
730		*/
731		public String toString() {
732	<	long s = state.get();
733	<	return super.toString() + "[phase = " + phaseOf(s) + " parties = " + partiesOf(s) + " arrived = " + arrivedOf(s) + "]";
732	>	long s = getReconciledState();
733	>	return super.toString() +
734	>	"[phase = " + phaseOf(s) +
735	>	" parties = " + partiesOf(s) +
736	>	" arrived = " + arrivedOf(s) + "]";
737		}
738
739	<	// methods for tripping and waiting
739	>	// methods for waiting
740
741		/**
742	<	* Advance the current phase (or terminate)
742	>	* Wait nodes for Treiber stack representing wait queue
743		*/
744	<	private void trip(int phase, int parties) {
745	<	int next = onAdvance(phase, parties)? -1 : ((phase + 1) & phaseMask);
746	<	state.set(stateFor(next, parties, parties));
747	<	if (head.get() != null)
748	<	releaseWaiters(next);
749	<	}
750	<
751	<	private int helpingWait(int phase) {
752	<	final AtomicLong state = this.state;
753	<	int p;
754	<	while ((p = phaseOf(state.get())) == phase) {
755	<	ForkJoinTask<?> t = ForkJoinWorkerThread.pollTask();
756	<	if (t != null) {
757	<	if ((p = phaseOf(state.get())) == phase)
758	<	t.exec();
759	<	else {   // push task and exit if barrier advanced
760	<	t.fork();
761	<	break;
762	<	}
744	>	static final class QNode implements ForkJoinPool.ManagedBlocker {
745	>	final Phaser phaser;
746	>	final int phase;
747	>	final long startTime;
748	>	final long nanos;
749	>	final boolean timed;
750	>	final boolean interruptible;
751	>	volatile boolean wasInterrupted = false;
752	>	volatile Thread thread; // nulled to cancel wait
753	>	QNode next;
754	>	QNode(Phaser phaser, int phase, boolean interruptible,
755	>	boolean timed, long startTime, long nanos) {
756	>	this.phaser = phaser;
757	>	this.phase = phase;
758	>	this.timed = timed;
759	>	this.interruptible = interruptible;
760	>	this.startTime = startTime;
761	>	this.nanos = nanos;
762	>	thread = Thread.currentThread();
763	>	}
764	>	public boolean isReleasable() {
765	>	return (thread == null ||
766	>	phaser.getPhase() != phase ||
767	>	(interruptible && wasInterrupted) ||
768	>	(timed && (nanos - (System.nanoTime() - startTime)) <= 0));
769	>	}
770	>	public boolean block() {
771	>	if (Thread.interrupted()) {
772	>	wasInterrupted = true;
773	>	if (interruptible)
774	>	return true;
775	>	}
776	>	if (!timed)
777	>	LockSupport.park(this);
778	>	else {
779	>	long waitTime = nanos - (System.nanoTime() - startTime);
780	>	if (waitTime <= 0)
781	>	return true;
782	>	LockSupport.parkNanos(this, waitTime);
783		}
784	+	return isReleasable();
785		}
786	<	return p;
787	<	}
506	<
507	<	private int timedHelpingWait(int phase, long nanos) throws TimeoutException {
508	<	final AtomicLong state = this.state;
509	<	long lastTime = System.nanoTime();
510	<	int p;
511	<	while ((p = phaseOf(state.get())) == phase) {
512	<	long now = System.nanoTime();
513	<	nanos -= now - lastTime;
514	<	lastTime = now;
515	<	if (nanos <= 0) {
516	<	if ((p = phaseOf(state.get())) == phase)
517	<	throw new TimeoutException();
518	<	else
519	<	break;
520	<	}
521	<	ForkJoinTask<?> t = ForkJoinWorkerThread.pollTask();
786	>	void signal() {
787	>	Thread t = thread;
788		if (t != null) {
789	<	if ((p = phaseOf(state.get())) == phase)
790	<	t.exec();
791	<	else {   // push task and exit if barrier advanced
792	<	t.fork();
793	<	break;
789	>	thread = null;
790	>	LockSupport.unpark(t);
791	>	}
792	>	}
793	>	boolean doWait() {
794	>	if (thread != null) {
795	>	try {
796	>	ForkJoinPool.managedBlock(this, false);
797	>	} catch (InterruptedException ie) {
798		}
799		}
800	+	return wasInterrupted;
801		}
802	<	return p;
802	>
803		}
804
805		/**
806	<	* Wait nodes for Treiber stack representing wait queue for non-FJ
536	<	* tasks. The waiting scheme is an adaptation of the one used in
537	<	* forkjoin.PoolBarrier.
806	>	* Removes and signals waiting threads from wait queue
807		*/
808	<	static final class QNode {
809	<	QNode next;
810	<	volatile Thread thread; // nulled to cancel wait
811	<	final int phase;
812	<	QNode(Thread t, int c) {
813	<	thread = t;
545	<	phase = c;
808	>	private void releaseWaiters(int phase) {
809	>	AtomicReference<QNode> head = queueFor(phase);
810	>	QNode q;
811	>	while ((q = head.get()) != null) {
812	>	if (head.compareAndSet(q, q.next))
813	>	q.signal();
814		}
815		}
816
549	–	private void releaseWaiters(int currentPhase) {
550	–	final AtomicReference<QNode> head = this.head;
551	–	QNode p;
552	–	while ((p = head.get()) != null && p.phase != currentPhase) {
553	–	if (head.compareAndSet(p, null)) {
554	–	do {
555	–	Thread t = p.thread;
556	–	if (t != null) {
557	–	p.thread = null;
558	–	LockSupport.unpark(t);
559	–	}
560	–	} while ((p = p.next) != null);
561	–	}
562	–	}
563	–	}
564	–
565	–	/** The number of CPUs, for spin control */
566	–	static final int NCPUS = Runtime.getRuntime().availableProcessors();
567	–
817		/**
818	<	* The number of times to spin before blocking in timed waits.
819	<	* The value is empirically derived.
818	>	* Tries to enqueue given node in the appropriate wait queue
819	>	* @return true if successful
820		*/
821	<	static final int maxTimedSpins = (NCPUS < 2)? 0 : 32;
822	<
823	<	/**
824	<	* The number of times to spin before blocking in untimed waits.
576	<	* This is greater than timed value because untimed waits spin
577	<	* faster since they don't need to check times on each spin.
578	<	*/
579	<	static final int maxUntimedSpins = maxTimedSpins * 32;
821	>	private boolean tryEnqueue(QNode node) {
822	>	AtomicReference<QNode> head = queueFor(node.phase);
823	>	return head.compareAndSet(node.next = head.get(), node);
824	>	}
825
826		/**
827	<	* The number of nanoseconds for which it is faster to spin
828	<	* rather than to use timed park. A rough estimate suffices.
827	>	* Enqueues node and waits unless aborted or signalled.
828	>	* @return current phase
829		*/
830	<	static final long spinForTimeoutThreshold = 1000L;
830	>	private int untimedWait(int phase) {
831	>	QNode node = null;
832	>	boolean queued = false;
833	>	boolean interrupted = false;
834	>	int p;
835	>	while ((p = getPhase()) == phase) {
836	>	if (Thread.interrupted())
837	>	interrupted = true;
838	>	else if (node == null)
839	>	node = new QNode(this, phase, false, false, 0, 0);
840	>	else if (!queued)
841	>	queued = tryEnqueue(node);
842	>	else
843	>	interrupted = node.doWait();
844	>	}
845	>	if (node != null)
846	>	node.thread = null;
847	>	releaseWaiters(phase);
848	>	if (interrupted)
849	>	Thread.currentThread().interrupt();
850	>	return p;
851	>	}
852
853		/**
854	<	* Enqueues node and waits unless aborted or signalled.
854	>	* Interruptible version
855	>	* @return current phase
856		*/
857	<	private boolean untimedWait(Thread thread, int currentPhase,
591	<	boolean abortOnInterrupt) {
592	<	final AtomicReference<QNode> head = this.head;
593	<	final AtomicLong state = this.state;
594	<	boolean wasInterrupted = false;
857	>	private int interruptibleWait(int phase) throws InterruptedException {
858		QNode node = null;
859		boolean queued = false;
860	<	int spins = maxUntimedSpins;
861	<	while (phaseOf(state.get()) == currentPhase) {
862	<	QNode h;
863	<	if (node != null && queued) {
864	<	if (node.thread != null) {
865	<	LockSupport.park();
866	<	if (Thread.interrupted()) {
867	<	wasInterrupted = true;
868	<	if (abortOnInterrupt)
606	<	break;
607	<	}
608	<	}
609	<	}
610	<	else if ((h = head.get()) != null && h.phase != currentPhase) {
611	<	if (phaseOf(state.get()) == currentPhase) { // must recheck
612	<	if (head.compareAndSet(h, h.next)) {
613	<	Thread t = h.thread; // help clear out old waiters
614	<	if (t != null) {
615	<	h.thread = null;
616	<	LockSupport.unpark(t);
617	<	}
618	<	}
619	<	}
620	<	else
621	<	break;
622	<	}
623	<	else if (node != null)
624	<	queued = head.compareAndSet(node.next = h, node);
625	<	else if (spins <= 0)
626	<	node = new QNode(thread, currentPhase);
860	>	boolean interrupted = false;
861	>	int p;
862	>	while ((p = getPhase()) == phase && !interrupted) {
863	>	if (Thread.interrupted())
864	>	interrupted = true;
865	>	else if (node == null)
866	>	node = new QNode(this, phase, true, false, 0, 0);
867	>	else if (!queued)
868	>	queued = tryEnqueue(node);
869		else
870	<	--spins;
870	>	interrupted = node.doWait();
871		}
872		if (node != null)
873		node.thread = null;
874	<	return wasInterrupted;
874	>	if (p != phase || (p = getPhase()) != phase)
875	>	releaseWaiters(phase);
876	>	if (interrupted)
877	>	throw new InterruptedException();
878	>	return p;
879		}
880
881		/**
882	<	* Messier timeout version
882	>	* Timeout version.
883	>	* @return current phase
884		*/
885	<	private void timedWait(Thread thread, int currentPhase, long nanos)
885	>	private int timedWait(int phase, long nanos)
886		throws InterruptedException, TimeoutException {
887	<	final AtomicReference<QNode> head = this.head;
641	<	final AtomicLong state = this.state;
642	<	long lastTime = System.nanoTime();
887	>	long startTime = System.nanoTime();
888		QNode node = null;
889		boolean queued = false;
890	<	int spins = maxTimedSpins;
891	<	while (phaseOf(state.get()) == currentPhase) {
892	<	QNode h;
893	<	long now = System.nanoTime();
894	<	nanos -= now - lastTime;
895	<	lastTime = now;
896	<	if (nanos <= 0) {
897	<	if (node != null)
898	<	node.thread = null;
899	<	if (phaseOf(state.get()) == currentPhase)
900	<	throw new TimeoutException();
656	<	else
657	<	break;
658	<	}
659	<	else if (node != null && queued) {
660	<	if (node.thread != null &&
661	<	nanos > spinForTimeoutThreshold) {
662	<	//                LockSupport.parkNanos(this, nanos);
663	<	LockSupport.parkNanos(nanos);
664	<	if (Thread.interrupted()) {
665	<	node.thread = null;
666	<	throw new InterruptedException();
667	<	}
668	<	}
669	<	}
670	<	else if ((h = head.get()) != null && h.phase != currentPhase) {
671	<	if (phaseOf(state.get()) == currentPhase) { // must recheck
672	<	if (head.compareAndSet(h, h.next)) {
673	<	Thread t = h.thread; // help clear out old waiters
674	<	if (t != null) {
675	<	h.thread = null;
676	<	LockSupport.unpark(t);
677	<	}
678	<	}
679	<	}
680	<	else
681	<	break;
682	<	}
683	<	else if (node != null)
684	<	queued = head.compareAndSet(node.next = h, node);
685	<	else if (spins <= 0)
686	<	node = new QNode(thread, currentPhase);
890	>	boolean interrupted = false;
891	>	int p;
892	>	while ((p = getPhase()) == phase && !interrupted) {
893	>	if (Thread.interrupted())
894	>	interrupted = true;
895	>	else if (nanos - (System.nanoTime() - startTime) <= 0)
896	>	break;
897	>	else if (node == null)
898	>	node = new QNode(this, phase, true, true, startTime, nanos);
899	>	else if (!queued)
900	>	queued = tryEnqueue(node);
901		else
902	<	--spins;
902	>	interrupted = node.doWait();
903		}
904		if (node != null)
905		node.thread = null;
906	+	if (p != phase || (p = getPhase()) != phase)
907	+	releaseWaiters(phase);
908	+	if (interrupted)
909	+	throw new InterruptedException();
910	+	if (p == phase)
911	+	throw new TimeoutException();
912	+	return p;
913		}
914
915	<	}
915	>	// Temporary Unsafe mechanics for preliminary release
916	>	private static Unsafe getUnsafe() throws Throwable {
917	>	try {
918	>	return Unsafe.getUnsafe();
919	>	} catch (SecurityException se) {
920	>	try {
921	>	return java.security.AccessController.doPrivileged
922	>	(new java.security.PrivilegedExceptionAction<Unsafe>() {
923	>	public Unsafe run() throws Exception {
924	>	return getUnsafePrivileged();
925	>	}});
926	>	} catch (java.security.PrivilegedActionException e) {
927	>	throw e.getCause();
928	>	}
929	>	}
930	>	}
931	>
932	>	private static Unsafe getUnsafePrivileged()
933	>	throws NoSuchFieldException, IllegalAccessException {
934	>	Field f = Unsafe.class.getDeclaredField("theUnsafe");
935	>	f.setAccessible(true);
936	>	return (Unsafe) f.get(null);
937	>	}
938	>
939	>	private static long fieldOffset(String fieldName)
940	>	throws NoSuchFieldException {
941	>	return _unsafe.objectFieldOffset
942	>	(Phaser.class.getDeclaredField(fieldName));
943	>	}
944
945	+	static final Unsafe _unsafe;
946	+	static final long stateOffset;
947	+
948	+	static {
949	+	try {
950	+	_unsafe = getUnsafe();
951	+	stateOffset = fieldOffset("state");
952	+	} catch (Throwable e) {
953	+	throw new RuntimeException("Could not initialize intrinsics", e);
954	+	}
955	+	}
956	+
957	+	final boolean casState(long cmp, long val) {
958	+	return _unsafe.compareAndSwapLong(this, stateOffset, cmp, val);
959	+	}
960	+	}

Diff Legend

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