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.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:	1.11
Committed:	Sat Dec 31 18:54:28 2016 UTC (7 years, 4 months ago) by jsr166
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.10:	+0 -2 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.locks.ReentrantLock;
13	dl	1.1
14			public final class CancelledLockLoops {
15			static final Random rng = new Random();
16			static boolean print = false;
17			static final int ITERS = 10000000;
18	jsr166	1.4	static final long TIMEOUT = 100;
19	dl	1.1
20			public static void main(String[] args) throws Exception {
21			int maxThreads = 100;
22	jsr166	1.4	if (args.length > 0)
23	dl	1.1	maxThreads = Integer.parseInt(args[0]);
24
25			print = true;
26
27			for (int i = 2; i <= maxThreads; i += (i+1) >>> 1) {
28			System.out.print("Threads: " + i);
29			try {
30			new ReentrantLockLoop(i).test();
31			}
32	jsr166	1.5	catch (BrokenBarrierException bb) {
33	dl	1.1	// OK, ignore
34			}
35			}
36			}
37
38			static final class ReentrantLockLoop implements Runnable {
39			private int v = rng.nextInt();
40			private int completed;
41			private volatile int result = 17;
42			private final ReentrantLock lock = new ReentrantLock();
43			private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
44			private final CyclicBarrier barrier;
45			private final int nthreads;
46			ReentrantLockLoop(int nthreads) {
47			this.nthreads = nthreads;
48			barrier = new CyclicBarrier(nthreads+1, timer);
49			}
50
51			final void test() throws Exception {
52			Thread[] threads = new Thread[nthreads];
53	jsr166	1.4	for (int i = 0; i < threads.length; ++i)
54	dl	1.1	threads[i] = new Thread(this);
55	jsr166	1.4	for (int i = 0; i < threads.length; ++i)
56	dl	1.1	threads[i].start();
57	jsr166	1.6	Thread[] cancels = threads.clone();
58	dl	1.1	Collections.shuffle(Arrays.asList(cancels), rng);
59			barrier.await();
60			Thread.sleep(TIMEOUT);
61			for (int i = 0; i < cancels.length-2; ++i) {
62			cancels[i].interrupt();
63			// make sure all OK even when cancellations spaced out
64	jsr166	1.4	if ( (i & 3) == 0)
65	dl	1.1	Thread.sleep(1 + rng.nextInt(10));
66			}
67			barrier.await();
68			if (print) {
69			long time = timer.getTime();
70	jsr166	1.7	double secs = (double) time / 1000000000.0;
71	dl	1.1	System.out.println("\t " + secs + "s run time");
72			}
73
74			int c;
75			lock.lock();
76			try {
77			c = completed;
78			}
79			finally {
80			lock.unlock();
81			}
82	jsr166	1.3	if (c != 2)
83	dl	1.1	throw new Error("Completed != 2");
84			int r = result;
85			if (r == 0) // avoid overoptimization
86			System.out.println("useless result: " + r);
87			}
88
89			public final void run() {
90			try {
91	jsr166	1.4	barrier.await();
92	dl	1.1	int sum = v;
93			int x = 0;
94			int n = ITERS;
95			boolean done = false;
96			do {
97			try {
98			lock.lockInterruptibly();
99			}
100			catch (InterruptedException ie) {
101			break;
102			}
103			try {
104			v = x = LoopHelpers.compute1(v);
105			}
106			finally {
107			lock.unlock();
108			}
109			sum += LoopHelpers.compute2(x);
110			} while (n-- > 0);
111			if (n <= 0) {
112	jsr166	1.4	lock.lock();
113	dl	1.1	try {
114			++completed;
115			}
116			finally {
117			lock.unlock();
118			}
119			}
120			barrier.await();
121			result += sum;
122			}
123	jsr166	1.4	catch (Exception ex) {
124	dl	1.1	// ex.printStackTrace();
125	jsr166	1.4	return;
126	dl	1.1	}
127			}
128			}
129
130			}