test/loops/SimpleTimedLockLoops.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.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReentrantLock;

public final class SimpleTimedLockLoops {
    static final ExecutorService pool = Executors.newCachedThreadPool();
    static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
    static boolean print = false;
    static int iters = 10000000;

    public static void main(String[] args) throws Exception {
        int maxThreads = 100;
        if (args.length > 0)
            maxThreads = Integer.parseInt(args[0]);

        print = true;

        int reps = 3;
        for (int i = 1; i <= maxThreads; i += (i+1) >>> 1) {
            int n = reps;
            if (reps > 1) --reps;
            while (n-- > 0) {
                System.out.print("Threads: " + i);
                new ReentrantLockLoop(i).test();
                Thread.sleep(100);
            }
        }
        pool.shutdown();
    }

    static final class ReentrantLockLoop implements Runnable {
        private int v = rng.next();
        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;
        private volatile int readBarrier;
        ReentrantLockLoop(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();
            barrier.await();
            if (print) {
                long time = timer.getTime();
                long tpi = time / ((long) iters * nthreads);
                System.out.print("\t" + LoopHelpers.rightJustify(tpi) + " ns per lock");
                double secs = (double) time / 1000000000.0;
                System.out.println("\t " + secs + "s run time");
            }

            int r = result;
            if (r == 0) // avoid overoptimization
                System.out.println("useless result: " + r);
        }

        public final void run() {
            final ReentrantLock lock = this.lock;
            try {
                barrier.await();
                int sum = v + 1;
                int x = 0;
                int n = iters;
                while (n > 0) {
                    if (lock.tryLock(1, TimeUnit.SECONDS)) {
                        --n;
                        int k = (sum & 3);
                        if (k > 0) {
                            x = v;
                            while (k-- > 0)
                                x = LoopHelpers.compute6(x);
                            v = x;
                        }
                        else x = sum + 1;
                        lock.unlock();
                    }
                    if ((x += readBarrier) == 0)
                        ++readBarrier;
                    for (int l = x & 7; l > 0; --l)
                        sum += LoopHelpers.compute6(sum);
                }
                barrier.await();
                result += sum;
            }
            catch (Exception ie) {
                return;
            }
        }
    }
}
Revision:	1.9
Committed:	Sat Dec 31 22:17:40 2016 UTC (7 years, 4 months ago) by jsr166
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.8:	+0 -1 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	1.3	* Expert Group and released to the public domain, as explained at
4	jsr166	1.6	* http://creativecommons.org/publicdomain/zero/1.0/
5	dl	1.1	*/
6
7	jsr166	1.8	import java.util.concurrent.CyclicBarrier;
8			import java.util.concurrent.ExecutorService;
9			import java.util.concurrent.Executors;
10			import java.util.concurrent.TimeUnit;
11			import java.util.concurrent.locks.ReentrantLock;
12	dl	1.1
13			public final class SimpleTimedLockLoops {
14			static final ExecutorService pool = Executors.newCachedThreadPool();
15			static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
16			static boolean print = false;
17			static int iters = 10000000;
18
19			public static void main(String[] args) throws Exception {
20			int maxThreads = 100;
21	jsr166	1.4	if (args.length > 0)
22	dl	1.1	maxThreads = Integer.parseInt(args[0]);
23
24			print = true;
25
26			int reps = 3;
27			for (int i = 1; i <= maxThreads; i += (i+1) >>> 1) {
28			int n = reps;
29			if (reps > 1) --reps;
30			while (n-- > 0) {
31			System.out.print("Threads: " + i);
32			new ReentrantLockLoop(i).test();
33			Thread.sleep(100);
34			}
35			}
36			pool.shutdown();
37			}
38
39			static final class ReentrantLockLoop implements Runnable {
40			private int v = rng.next();
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			private volatile int readBarrier;
47			ReentrantLockLoop(int nthreads) {
48			this.nthreads = nthreads;
49			barrier = new CyclicBarrier(nthreads+1, timer);
50			}
51
52			final void test() throws Exception {
53	jsr166	1.4	for (int i = 0; i < nthreads; ++i)
54	dl	1.1	pool.execute(this);
55			barrier.await();
56			barrier.await();
57			if (print) {
58			long time = timer.getTime();
59	jsr166	1.5	long tpi = time / ((long) iters * nthreads);
60	dl	1.1	System.out.print("\t" + LoopHelpers.rightJustify(tpi) + " ns per lock");
61	jsr166	1.5	double secs = (double) time / 1000000000.0;
62	dl	1.1	System.out.println("\t " + secs + "s run time");
63			}
64
65			int r = result;
66			if (r == 0) // avoid overoptimization
67			System.out.println("useless result: " + r);
68			}
69
70			public final void run() {
71			final ReentrantLock lock = this.lock;
72			try {
73	jsr166	1.4	barrier.await();
74	dl	1.1	int sum = v + 1;
75			int x = 0;
76			int n = iters;
77			while (n > 0) {
78			if (lock.tryLock(1, TimeUnit.SECONDS)) {
79			--n;
80			int k = (sum & 3);
81			if (k > 0) {
82			x = v;
83			while (k-- > 0)
84	dl	1.2	x = LoopHelpers.compute6(x);
85	dl	1.1	v = x;
86			}
87			else x = sum + 1;
88			lock.unlock();
89			}
90			if ((x += readBarrier) == 0)
91			++readBarrier;
92			for (int l = x & 7; l > 0; --l)
93	dl	1.2	sum += LoopHelpers.compute6(sum);
94	jsr166	1.4	}
95	dl	1.1	barrier.await();
96			result += sum;
97			}
98	jsr166	1.4	catch (Exception ie) {
99			return;
100	dl	1.1	}
101			}
102			}
103			}