test/loops/TimeoutLockLoops.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
 * @bug 4486658
 * @run main TimeoutLockLoops
 * @summary Checks for responsiveness of locks to timeouts.
 * Runs under the assumption that ITERS computations require more than
 * TIMEOUT msecs to complete, which seems to be a safe assumption for
 * another decade.
 */

import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReentrantLock;

public final class TimeoutLockLoops {
    static final ExecutorService pool = Executors.newCachedThreadPool();
    static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
    static boolean print = false;
    static final int ITERS = Integer.MAX_VALUE;
    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 = 1; i <= maxThreads; i += (i+1) >>> 1) {
            System.out.print("Threads: " + i);
            new ReentrantLockLoop(i).test();
            //            Thread.sleep(10);
        }
        pool.shutdown();
    }

    static final class ReentrantLockLoop implements Runnable {
        private int v = rng.next();
        private volatile boolean completed;
        private volatile int result = 17;
        private final ReentrantLock lock = new ReentrantLock();
        private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
        private final CyclicBarrier barrier;
        private final int nthreads;
        ReentrantLockLoop(int nthreads) {
            this.nthreads = nthreads;
            barrier = new CyclicBarrier(nthreads+1, timer);
        }

        final void test() throws Exception {
            for (int i = 0; i < nthreads; ++i) {
                lock.lock();
                pool.execute(this);
                lock.unlock();
            }
            barrier.await();
            Thread.sleep(TIMEOUT);
            while (!lock.tryLock()); // Jam lock
            //            lock.lock();
            barrier.await();
            if (print) {
                long time = timer.getTime();
                double secs = (double) time / 1000000000.0;
                System.out.println("\t " + secs + "s run time");
            }

            if (completed)
                throw new Error("Some thread completed instead of timing out");
            int r = result;
            if (r == 0) // avoid overoptimization
                System.out.println("useless result: " + r);
        }

        public final void run() {
            try {
                barrier.await();
                int sum = v;
                int x = 17;
                int n = ITERS;
                final ReentrantLock lock = this.lock;
                for (;;) {
                    if (x != 0) {
                        if (n-- <= 0)
                            break;
                    }
                    if (!lock.tryLock(TIMEOUT, TimeUnit.MILLISECONDS))
                        break;
                    try {
                        v = x = LoopHelpers.compute1(v);
                    }
                    finally {
                        lock.unlock();
                    }
                    sum += LoopHelpers.compute2(x);
                }
                if (n <= 0)
                    completed = true;
                barrier.await();
                result += sum;
            }
            catch (Exception ex) {
                ex.printStackTrace();
                return;
            }
        }
    }
}
Revision:	1.10
Committed:	Sat Dec 31 18:54:28 2016 UTC (7 years, 4 months ago) by jsr166
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.9:	+5 -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	1.6	* http://creativecommons.org/publicdomain/zero/1.0/
5	dl	1.2	*/
6			/*
7	jsr166	1.3	* @test
8	dl	1.1	* @bug 4486658
9			* @run main TimeoutLockLoops
10			* @summary Checks for responsiveness of locks to timeouts.
11			* Runs under the assumption that ITERS computations require more than
12			* TIMEOUT msecs to complete, which seems to be a safe assumption for
13			* another decade.
14			*/
15
16	jsr166	1.10	import java.util.concurrent.CyclicBarrier;
17			import java.util.concurrent.ExecutorService;
18			import java.util.concurrent.Executors;
19			import java.util.concurrent.TimeUnit;
20			import java.util.concurrent.locks.ReentrantLock;
21	dl	1.1
22			public final class TimeoutLockLoops {
23			static final ExecutorService pool = Executors.newCachedThreadPool();
24			static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
25			static boolean print = false;
26			static final int ITERS = Integer.MAX_VALUE;
27	jsr166	1.4	static final long TIMEOUT = 100;
28	dl	1.1
29			public static void main(String[] args) throws Exception {
30			int maxThreads = 100;
31	jsr166	1.4	if (args.length > 0)
32	dl	1.1	maxThreads = Integer.parseInt(args[0]);
33
34			print = true;
35
36			for (int i = 1; i <= maxThreads; i += (i+1) >>> 1) {
37			System.out.print("Threads: " + i);
38			new ReentrantLockLoop(i).test();
39			// Thread.sleep(10);
40			}
41			pool.shutdown();
42			}
43
44			static final class ReentrantLockLoop implements Runnable {
45			private int v = rng.next();
46			private volatile boolean completed;
47			private volatile int result = 17;
48			private final ReentrantLock lock = new ReentrantLock();
49			private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
50			private final CyclicBarrier barrier;
51			private final int nthreads;
52			ReentrantLockLoop(int nthreads) {
53			this.nthreads = nthreads;
54			barrier = new CyclicBarrier(nthreads+1, timer);
55			}
56
57			final void test() throws Exception {
58			for (int i = 0; i < nthreads; ++i) {
59			lock.lock();
60			pool.execute(this);
61			lock.unlock();
62			}
63			barrier.await();
64			Thread.sleep(TIMEOUT);
65			while (!lock.tryLock()); // Jam lock
66			// lock.lock();
67			barrier.await();
68			if (print) {
69			long time = timer.getTime();
70	jsr166	1.5	double secs = (double) time / 1000000000.0;
71	dl	1.1	System.out.println("\t " + secs + "s run time");
72			}
73
74			if (completed)
75			throw new Error("Some thread completed instead of timing out");
76			int r = result;
77			if (r == 0) // avoid overoptimization
78			System.out.println("useless result: " + r);
79			}
80
81			public final void run() {
82			try {
83	jsr166	1.4	barrier.await();
84	dl	1.1	int sum = v;
85			int x = 17;
86			int n = ITERS;
87			final ReentrantLock lock = this.lock;
88			for (;;) {
89			if (x != 0) {
90			if (n-- <= 0)
91			break;
92			}
93			if (!lock.tryLock(TIMEOUT, TimeUnit.MILLISECONDS))
94			break;
95			try {
96			v = x = LoopHelpers.compute1(v);
97			}
98			finally {
99			lock.unlock();
100			}
101			sum += LoopHelpers.compute2(x);
102			}
103			if (n <= 0)
104			completed = true;
105			barrier.await();
106			result += sum;
107			}
108	jsr166	1.4	catch (Exception ex) {
109	dl	1.1	ex.printStackTrace();
110	jsr166	1.4	return;
111	dl	1.1	}
112			}
113			}
114			}