test/loops/CancelledFutureLoops.java

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */

/*
 * @test
 * @summary Checks for responsiveness of futures to cancellation.
 * Runs under
 * the assumption that ITERS computations require more than TIMEOUT
 * msecs to complete.
 */

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain. Use, modify, and
 * redistribute this code in any way without acknowledgement.
 */

import java.util.concurrent.Callable;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.locks.ReentrantLock;

public final class CancelledFutureLoops {
    static final ExecutorService pool = Executors.newCachedThreadPool();
    static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
    static boolean print = false;
    static final int ITERS = 10000000;
    static final long TIMEOUT = 100;

    public static void main(String[] args) throws Exception {
        int maxThreads = 100;
        if (args.length > 0)
            maxThreads = Integer.parseInt(args[0]);

        print = true;

        for (int i = 2; i <= maxThreads; i += (i+1) >>> 1) {
            System.out.print("Threads: " + i);
            new FutureLoop(i).test();
            Thread.sleep(TIMEOUT);
        }
        pool.shutdown();
    }

    static final class FutureLoop implements Callable<Object> {
        private int v = rng.next();
        private final ReentrantLock lock = new ReentrantLock();
        private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
        private final CyclicBarrier barrier;
        private final int nthreads;
        FutureLoop(int nthreads) {
            this.nthreads = nthreads;
            barrier = new CyclicBarrier(nthreads+1, timer);
        }

        final void test() throws Exception {
            Future<?>[] futures = new Future<?>[nthreads];
            for (int i = 0; i < nthreads; ++i)
                futures[i] = pool.submit(this);

            barrier.await();
            Thread.sleep(TIMEOUT);
            boolean tooLate = false;
            for (int i = 1; i < nthreads; ++i) {
                if (!futures[i].cancel(true))
                    tooLate = true;
                // Unbunch some of the cancels
                if ( (i & 3) == 0)
                    Thread.sleep(1 + rng.next() % 10);
            }

            Object f0 = futures[0].get();
            if (!tooLate) {
                for (int i = 1; i < nthreads; ++i) {
                    if (!futures[i].isDone() || !futures[i].isCancelled())
                        throw new Error("Only one thread should complete");
                }
            }
            else
                System.out.print("(cancelled too late) ");

            long endTime = System.nanoTime();
            long time = endTime - timer.startTime;
            if (print) {
                double secs = (double) time / 1000000000.0;
                System.out.println("\t " + secs + "s run time");
            }

        }

        public final Object call() throws Exception {
            barrier.await();
            int sum = v;
            int x = 0;
            int n = ITERS;
            while (n-- > 0) {
                lock.lockInterruptibly();
                try {
                    v = x = LoopHelpers.compute1(v);
                }
                finally {
                    lock.unlock();
                }
                sum += LoopHelpers.compute2(LoopHelpers.compute2(x));
            }
            return new Integer(sum);
        }
    }

}
Revision:	1.9
Committed:	Sat Dec 31 19:34:08 2016 UTC (7 years, 4 months ago) by jsr166
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.8:	+6 -3 lines
Log Message:	organize imports
#	User	Rev	Content
1	dl	1.1	/*
2	dl	1.2	* Written by Doug Lea with assistance from members of JCP JSR-166
3			* Expert Group and released to the public domain, as explained at
4	jsr166	1.5	* http://creativecommons.org/publicdomain/zero/1.0/
5	dl	1.2	*/
6
7			/*
8	dl	1.1	* @test
9	jsr166	1.3	* @summary Checks for responsiveness of futures to cancellation.
10	dl	1.1	* Runs under
11			* the assumption that ITERS computations require more than TIMEOUT
12			* msecs to complete.
13			*/
14
15			/*
16			* Written by Doug Lea with assistance from members of JCP JSR-166
17			* Expert Group and released to the public domain. Use, modify, and
18			* redistribute this code in any way without acknowledgement.
19			*/
20
21	jsr166	1.9	import java.util.concurrent.Callable;
22			import java.util.concurrent.CyclicBarrier;
23			import java.util.concurrent.ExecutorService;
24			import java.util.concurrent.Executors;
25			import java.util.concurrent.Future;
26			import java.util.concurrent.locks.ReentrantLock;
27	dl	1.1
28			public final class CancelledFutureLoops {
29			static final ExecutorService pool = Executors.newCachedThreadPool();
30			static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
31			static boolean print = false;
32			static final int ITERS = 10000000;
33	jsr166	1.3	static final long TIMEOUT = 100;
34	dl	1.1
35			public static void main(String[] args) throws Exception {
36			int maxThreads = 100;
37	jsr166	1.3	if (args.length > 0)
38	dl	1.1	maxThreads = Integer.parseInt(args[0]);
39
40			print = true;
41
42			for (int i = 2; i <= maxThreads; i += (i+1) >>> 1) {
43			System.out.print("Threads: " + i);
44			new FutureLoop(i).test();
45			Thread.sleep(TIMEOUT);
46			}
47			pool.shutdown();
48			}
49
50	jsr166	1.8	static final class FutureLoop implements Callable<Object> {
51	dl	1.1	private int v = rng.next();
52			private final ReentrantLock lock = new ReentrantLock();
53			private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
54			private final CyclicBarrier barrier;
55			private final int nthreads;
56			FutureLoop(int nthreads) {
57			this.nthreads = nthreads;
58			barrier = new CyclicBarrier(nthreads+1, timer);
59			}
60
61			final void test() throws Exception {
62	jsr166	1.6	Future<?>[] futures = new Future<?>[nthreads];
63	jsr166	1.3	for (int i = 0; i < nthreads; ++i)
64	dl	1.1	futures[i] = pool.submit(this);
65
66			barrier.await();
67			Thread.sleep(TIMEOUT);
68			boolean tooLate = false;
69			for (int i = 1; i < nthreads; ++i) {
70			if (!futures[i].cancel(true))
71			tooLate = true;
72			// Unbunch some of the cancels
73	jsr166	1.3	if ( (i & 3) == 0)
74	dl	1.1	Thread.sleep(1 + rng.next() % 10);
75			}
76
77			Object f0 = futures[0].get();
78			if (!tooLate) {
79			for (int i = 1; i < nthreads; ++i) {
80			if (!futures[i].isDone() \|\| !futures[i].isCancelled())
81			throw new Error("Only one thread should complete");
82			}
83			}
84			else
85			System.out.print("(cancelled too late) ");
86	jsr166	1.3
87	dl	1.1	long endTime = System.nanoTime();
88			long time = endTime - timer.startTime;
89			if (print) {
90	jsr166	1.4	double secs = (double) time / 1000000000.0;
91	dl	1.1	System.out.println("\t " + secs + "s run time");
92			}
93
94			}
95
96			public final Object call() throws Exception {
97	jsr166	1.3	barrier.await();
98	dl	1.1	int sum = v;
99			int x = 0;
100			int n = ITERS;
101			while (n-- > 0) {
102			lock.lockInterruptibly();
103			try {
104			v = x = LoopHelpers.compute1(v);
105			}
106			finally {
107			lock.unlock();
108			}
109			sum += LoopHelpers.compute2(LoopHelpers.compute2(x));
110	jsr166	1.3	}
111	dl	1.1	return new Integer(sum);
112			}
113			}
114
115			}