test/loops/TimeoutMutexLoops.java

/*
 * @test
 * 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.*;
import java.util.concurrent.locks.*;
import java.util.*;

public final class TimeoutMutexLoops {
    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 MutexLoop(i).test();
            Thread.sleep(TIMEOUT);
        }
        pool.shutdown();
    }

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

        final void test() throws Exception {
            for (int i = 0; i < nthreads; ++i) 
                pool.execute(this);
            barrier.await();
            Thread.sleep(TIMEOUT);
            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 = 0;
                int n = ITERS;
                do {
                    if (!lock.tryLock(TIMEOUT, TimeUnit.MILLISECONDS))
                        break;
                    try {
                        v = x = LoopHelpers.compute1(v);
                    }
                    finally {
                        lock.unlock();
                    }
                    sum += LoopHelpers.compute2(x);
                } while (n-- > 0);
                if (n <= 0)
                    completed = true;
                barrier.await();
                result += sum;
            }
            catch (Exception ie) { 
                return; 
            }
        }
    }

}
Revision:	1.1
Committed:	Mon May 2 19:19:38 2005 UTC (19 years ago) by dl
Branch:	MAIN
Log Message:	Put misc performance tests into CVS
#	Content
1	/*
2	* @test
3	* Checks for responsiveness of locks to timeouts. Runs under the
4	* assumption that ITERS computations require more than TIMEOUT msecs
5	* to complete, which seems to be a safe assumption for another
6	* decade.
7	*/
8
9	import java.util.concurrent.*;
10	import java.util.concurrent.locks.*;
11	import java.util.*;
12
13	public final class TimeoutMutexLoops {
14	static final ExecutorService pool = Executors.newCachedThreadPool();
15	static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
16	static boolean print = false;
17	static final int ITERS = Integer.MAX_VALUE;
18	static final long TIMEOUT = 100;
19
20	public static void main(String[] args) throws Exception {
21	int maxThreads = 100;
22	if (args.length > 0)
23	maxThreads = Integer.parseInt(args[0]);
24
25	print = true;
26
27	for (int i = 1; i <= maxThreads; i += (i+1) >>> 1) {
28	System.out.print("Threads: " + i);
29	new MutexLoop(i).test();
30	Thread.sleep(TIMEOUT);
31	}
32	pool.shutdown();
33	}
34
35	static final class MutexLoop implements Runnable {
36	private int v = rng.next();
37	private volatile boolean completed;
38	private volatile int result = 17;
39	private final Mutex lock = new Mutex();
40	private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
41	private final CyclicBarrier barrier;
42	private final int nthreads;
43	MutexLoop(int nthreads) {
44	this.nthreads = nthreads;
45	barrier = new CyclicBarrier(nthreads+1, timer);
46	}
47
48	final void test() throws Exception {
49	for (int i = 0; i < nthreads; ++i)
50	pool.execute(this);
51	barrier.await();
52	Thread.sleep(TIMEOUT);
53	lock.lock();
54	barrier.await();
55	if (print) {
56	long time = timer.getTime();
57	double secs = (double)(time) / 1000000000.0;
58	System.out.println("\t " + secs + "s run time");
59	}
60
61	if (completed)
62	throw new Error("Some thread completed instead of timing out");
63	int r = result;
64	if (r == 0) // avoid overoptimization
65	System.out.println("useless result: " + r);
66	}
67
68	public final void run() {
69	try {
70	barrier.await();
71	int sum = v;
72	int x = 0;
73	int n = ITERS;
74	do {
75	if (!lock.tryLock(TIMEOUT, TimeUnit.MILLISECONDS))
76	break;
77	try {
78	v = x = LoopHelpers.compute1(v);
79	}
80	finally {
81	lock.unlock();
82	}
83	sum += LoopHelpers.compute2(x);
84	} while (n-- > 0);
85	if (n <= 0)
86	completed = true;
87	barrier.await();
88	result += sum;
89	}
90	catch (Exception ie) {
91	return;
92	}
93	}
94	}
95
96	}