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.concurrent.*;
import java.util.concurrent.locks.*;
import java.util.*;

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:	1.8
Committed:	Tue Mar 15 19:47:05 2011 UTC (13 years, 1 month ago) by jsr166
Branch:	MAIN
CVS Tags:	release-1_7_0
Changes since 1.7:	+1 -1 lines
Log Message:	Update Creative Commons license URL in legal notices
#	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			import java.util.concurrent.*;
8			import java.util.concurrent.locks.*;
9			import java.util.*;
10
11			public final class CancelledLockLoops {
12			static final Random rng = new Random();
13			static boolean print = false;
14			static final int ITERS = 10000000;
15	jsr166	1.4	static final long TIMEOUT = 100;
16	dl	1.1
17			public static void main(String[] args) throws Exception {
18			int maxThreads = 100;
19	jsr166	1.4	if (args.length > 0)
20	dl	1.1	maxThreads = Integer.parseInt(args[0]);
21
22			print = true;
23
24			for (int i = 2; i <= maxThreads; i += (i+1) >>> 1) {
25			System.out.print("Threads: " + i);
26			try {
27			new ReentrantLockLoop(i).test();
28			}
29	jsr166	1.5	catch (BrokenBarrierException bb) {
30	dl	1.1	// OK, ignore
31			}
32			}
33			}
34
35			static final class ReentrantLockLoop implements Runnable {
36			private int v = rng.nextInt();
37			private int completed;
38			private volatile int result = 17;
39			private final ReentrantLock lock = new ReentrantLock();
40			private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
41			private final CyclicBarrier barrier;
42			private final int nthreads;
43			ReentrantLockLoop(int nthreads) {
44			this.nthreads = nthreads;
45			barrier = new CyclicBarrier(nthreads+1, timer);
46			}
47
48			final void test() throws Exception {
49			Thread[] threads = new Thread[nthreads];
50	jsr166	1.4	for (int i = 0; i < threads.length; ++i)
51	dl	1.1	threads[i] = new Thread(this);
52	jsr166	1.4	for (int i = 0; i < threads.length; ++i)
53	dl	1.1	threads[i].start();
54	jsr166	1.6	Thread[] cancels = threads.clone();
55	dl	1.1	Collections.shuffle(Arrays.asList(cancels), rng);
56			barrier.await();
57			Thread.sleep(TIMEOUT);
58			for (int i = 0; i < cancels.length-2; ++i) {
59			cancels[i].interrupt();
60			// make sure all OK even when cancellations spaced out
61	jsr166	1.4	if ( (i & 3) == 0)
62	dl	1.1	Thread.sleep(1 + rng.nextInt(10));
63			}
64			barrier.await();
65			if (print) {
66			long time = timer.getTime();
67	jsr166	1.7	double secs = (double) time / 1000000000.0;
68	dl	1.1	System.out.println("\t " + secs + "s run time");
69			}
70
71			int c;
72			lock.lock();
73			try {
74			c = completed;
75			}
76			finally {
77			lock.unlock();
78			}
79	jsr166	1.3	if (c != 2)
80	dl	1.1	throw new Error("Completed != 2");
81			int r = result;
82			if (r == 0) // avoid overoptimization
83			System.out.println("useless result: " + r);
84			}
85
86			public final void run() {
87			try {
88	jsr166	1.4	barrier.await();
89	dl	1.1	int sum = v;
90			int x = 0;
91			int n = ITERS;
92			boolean done = false;
93			do {
94			try {
95			lock.lockInterruptibly();
96			}
97			catch (InterruptedException ie) {
98			break;
99			}
100			try {
101			v = x = LoopHelpers.compute1(v);
102			}
103			finally {
104			lock.unlock();
105			}
106			sum += LoopHelpers.compute2(x);
107			} while (n-- > 0);
108			if (n <= 0) {
109	jsr166	1.4	lock.lock();
110	dl	1.1	try {
111			++completed;
112			}
113			finally {
114			lock.unlock();
115			}
116			}
117			barrier.await();
118			result += sum;
119			}
120	jsr166	1.4	catch (Exception ex) {
121	dl	1.1	// ex.printStackTrace();
122	jsr166	1.4	return;
123	dl	1.1	}
124			}
125			}
126
127			}