test/loops/CancelledLockLoops.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/
 */

import java.util.Arrays;
import java.util.Collections;
import java.util.Random;
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.ReentrantLock;

public final class CancelledLockLoops {
    static final Random rng = new Random();
    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);
            try {
                new ReentrantLockLoop(i).test();
            }
            catch (BrokenBarrierException bb) {
                // OK, ignore
            }
        }
    }

    static final class ReentrantLockLoop implements Runnable {
        private int v = rng.nextInt();
        private int 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 {
            Thread[] threads = new Thread[nthreads];
            for (int i = 0; i < threads.length; ++i)
                threads[i] = new Thread(this);
            for (int i = 0; i < threads.length; ++i)
                threads[i].start();
            Thread[] cancels = threads.clone();
            Collections.shuffle(Arrays.asList(cancels), rng);
            barrier.await();
            Thread.sleep(TIMEOUT);
            for (int i = 0; i < cancels.length-2; ++i) {
                cancels[i].interrupt();
                // make sure all OK even when cancellations spaced out
                if ( (i & 3) == 0)
                    Thread.sleep(1 + rng.nextInt(10));
            }
            barrier.await();
            if (print) {
                long time = timer.getTime();
                double secs = (double) time / 1000000000.0;
                System.out.println("\t " + secs + "s run time");
            }

            int c;
            lock.lock();
            try {
                c = completed;
            }
            finally {
                lock.unlock();
            }
            if (c != 2)
                throw new Error("Completed != 2");
            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 = 0;
                int n = ITERS;
                boolean done = false;
                do {
                    try {
                        lock.lockInterruptibly();
                    }
                    catch (InterruptedException ie) {
                        break;
                    }
                    try {
                        v = x = LoopHelpers.compute1(v);
                    }
                    finally {
                        lock.unlock();
                    }
                    sum += LoopHelpers.compute2(x);
                } while (n-- > 0);
                if (n <= 0) {
                    lock.lock();
                    try {
                        ++completed;
                    }
                    finally {
                        lock.unlock();
                    }
                }
                barrier.await();
                result += sum;
            }
            catch (Exception ex) {
                //                ex.printStackTrace();
                return;
            }
        }
    }

}
Revision:	1.10
Committed:	Sat Dec 31 04:10:36 2016 UTC (7 years, 4 months ago) by jsr166
Branch:	MAIN
Changes since 1.9:	+8 -3 lines
Log Message:	organize imports
#	User	Rev	Content
1	dl	1.1	/*
2			* Written by Doug Lea with assistance from members of JCP JSR-166
3	dl	1.2	* Expert Group and released to the public domain, as explained at
4	jsr166	1.8	* http://creativecommons.org/publicdomain/zero/1.0/
5	dl	1.1	*/
6
7	jsr166	1.10	import java.util.Arrays;
8			import java.util.Collections;
9			import java.util.Random;
10			import java.util.concurrent.BrokenBarrierException;
11			import java.util.concurrent.CyclicBarrier;
12			import java.util.concurrent.ExecutorService;
13			import java.util.concurrent.Executors;
14			import java.util.concurrent.locks.ReentrantLock;
15	dl	1.1
16			public final class CancelledLockLoops {
17			static final Random rng = new Random();
18			static boolean print = false;
19			static final int ITERS = 10000000;
20	jsr166	1.4	static final long TIMEOUT = 100;
21	dl	1.1
22			public static void main(String[] args) throws Exception {
23			int maxThreads = 100;
24	jsr166	1.4	if (args.length > 0)
25	dl	1.1	maxThreads = Integer.parseInt(args[0]);
26
27			print = true;
28
29			for (int i = 2; i <= maxThreads; i += (i+1) >>> 1) {
30			System.out.print("Threads: " + i);
31			try {
32			new ReentrantLockLoop(i).test();
33			}
34	jsr166	1.5	catch (BrokenBarrierException bb) {
35	dl	1.1	// OK, ignore
36			}
37			}
38			}
39
40			static final class ReentrantLockLoop implements Runnable {
41			private int v = rng.nextInt();
42			private int completed;
43			private volatile int result = 17;
44			private final ReentrantLock lock = new ReentrantLock();
45			private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
46			private final CyclicBarrier barrier;
47			private final int nthreads;
48			ReentrantLockLoop(int nthreads) {
49			this.nthreads = nthreads;
50			barrier = new CyclicBarrier(nthreads+1, timer);
51			}
52
53			final void test() throws Exception {
54			Thread[] threads = new Thread[nthreads];
55	jsr166	1.4	for (int i = 0; i < threads.length; ++i)
56	dl	1.1	threads[i] = new Thread(this);
57	jsr166	1.4	for (int i = 0; i < threads.length; ++i)
58	dl	1.1	threads[i].start();
59	jsr166	1.6	Thread[] cancels = threads.clone();
60	dl	1.1	Collections.shuffle(Arrays.asList(cancels), rng);
61			barrier.await();
62			Thread.sleep(TIMEOUT);
63			for (int i = 0; i < cancels.length-2; ++i) {
64			cancels[i].interrupt();
65			// make sure all OK even when cancellations spaced out
66	jsr166	1.4	if ( (i & 3) == 0)
67	dl	1.1	Thread.sleep(1 + rng.nextInt(10));
68			}
69			barrier.await();
70			if (print) {
71			long time = timer.getTime();
72	jsr166	1.7	double secs = (double) time / 1000000000.0;
73	dl	1.1	System.out.println("\t " + secs + "s run time");
74			}
75
76			int c;
77			lock.lock();
78			try {
79			c = completed;
80			}
81			finally {
82			lock.unlock();
83			}
84	jsr166	1.3	if (c != 2)
85	dl	1.1	throw new Error("Completed != 2");
86			int r = result;
87			if (r == 0) // avoid overoptimization
88			System.out.println("useless result: " + r);
89			}
90
91			public final void run() {
92			try {
93	jsr166	1.4	barrier.await();
94	dl	1.1	int sum = v;
95			int x = 0;
96			int n = ITERS;
97			boolean done = false;
98			do {
99			try {
100			lock.lockInterruptibly();
101			}
102			catch (InterruptedException ie) {
103			break;
104			}
105			try {
106			v = x = LoopHelpers.compute1(v);
107			}
108			finally {
109			lock.unlock();
110			}
111			sum += LoopHelpers.compute2(x);
112			} while (n-- > 0);
113			if (n <= 0) {
114	jsr166	1.4	lock.lock();
115	dl	1.1	try {
116			++completed;
117			}
118			finally {
119			lock.unlock();
120			}
121			}
122			barrier.await();
123			result += sum;
124			}
125	jsr166	1.4	catch (Exception ex) {
126	dl	1.1	// ex.printStackTrace();
127	jsr166	1.4	return;
128	dl	1.1	}
129			}
130			}
131
132			}