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
#	User	Rev	Content
1	dl	1.1	/*
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			}