test/jsr166e/DoubleAdderDemo.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.Phaser;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicLong;
import jsr166e.DoubleAdder;

public class DoubleAdderDemo {
    static final int INCS_PER_THREAD = 10000000;
    static final int NCPU = Runtime.getRuntime().availableProcessors();
    static final ExecutorService pool = Executors.newCachedThreadPool();

    static final class SynchronizedDoubleAdder {
        double value;
        synchronized double sum() { return value; }
        synchronized void add(double x) { value += x; }
    }

    public static void main(String[] args) {
        System.out.println("Warmup...");
        int half = NCPU > 1 ? NCPU / 2 : 1;
        syncTest(half, 1000);
        adderTest(half, 1000);

        for (int reps = 0; reps < 2; ++reps) {
            System.out.println("Running...");
            for (int i = 1; i <= NCPU * 2; i <<= 1) {
                syncTest(i, INCS_PER_THREAD);
                adderTest(i, INCS_PER_THREAD);
            }
        }
        pool.shutdown();
    }

    static void syncTest(int nthreads, int incs) {
        System.out.print("Synchronized ");
        Phaser phaser = new Phaser(nthreads + 1);
        SynchronizedDoubleAdder a = new SynchronizedDoubleAdder();
        for (int i = 0; i < nthreads; ++i)
            pool.execute(new SyncTask(a, phaser, incs));
        report(nthreads, incs, timeTasks(phaser), a.sum());
    }

    static void adderTest(int nthreads, int incs) {
        System.out.print("DoubleAdder  ");
        Phaser phaser = new Phaser(nthreads + 1);
        DoubleAdder a = new DoubleAdder();
        for (int i = 0; i < nthreads; ++i)
            pool.execute(new AdderTask(a, phaser, incs));
        report(nthreads, incs, timeTasks(phaser), a.sum());
    }

    static void report(int nthreads, int incs, long time, double sum) {
        long total = (long)nthreads * incs;
        if (sum != (double)total)
            throw new Error(sum + " != " + total);
        double secs = (double)time / (1000L * 1000 * 1000);
        long rate = total * (1000L) / time;
        System.out.printf("threads:%3d  Time: %7.3fsec  Incs per microsec: %4d\n",
                          nthreads, secs, rate);
    }

    static long timeTasks(Phaser phaser) {
        phaser.arriveAndAwaitAdvance();
        long start = System.nanoTime();
        phaser.arriveAndAwaitAdvance();
        phaser.arriveAndAwaitAdvance();
        return System.nanoTime() - start;
    }

    static final class AdderTask implements Runnable {
        final DoubleAdder adder;
        final Phaser phaser;
        final int incs;
        volatile double result;
        AdderTask(DoubleAdder adder, Phaser phaser, int incs) {
            this.adder = adder;
            this.phaser = phaser;
            this.incs = incs;
        }

        public void run() {
            phaser.arriveAndAwaitAdvance();
            phaser.arriveAndAwaitAdvance();
            DoubleAdder a = adder;
            for (int i = 0; i < incs; ++i)
                a.add(1.0);
            result = a.sum();
            phaser.arrive();
        }
    }

    static final class SyncTask implements Runnable {
        final SynchronizedDoubleAdder adder;
        final Phaser phaser;
        final int incs;
        volatile double result;
        SyncTask(SynchronizedDoubleAdder adder, Phaser phaser, int incs) {
            this.adder = adder;
            this.phaser = phaser;
            this.incs = incs;
        }

        public void run() {
            phaser.arriveAndAwaitAdvance();
            phaser.arriveAndAwaitAdvance();
            SynchronizedDoubleAdder a = adder;
            for (int i = 0; i < incs; ++i)
                a.add(1.0);
            result = a.sum();
            phaser.arrive();
        }
    }

}
Revision:	1.2
Committed:	Tue Aug 2 18:22:20 2011 UTC (12 years, 10 months ago) by jsr166
Branch:	MAIN
Changes since 1.1:	+6 -6 lines
Log Message:	whitespace
#	User	Rev	Content
1	dl	1.1	/*
2			* Written by Doug Lea with assistance from members of JCP JSR-166
3			* Expert Group and released to the public domain, as explained at
4			* http://creativecommons.org/publicdomain/zero/1.0/
5			*/
6
7			import java.util.concurrent.Phaser;
8			import java.util.concurrent.ExecutorService;
9			import java.util.concurrent.Executors;
10			import java.util.concurrent.atomic.AtomicLong;
11			import jsr166e.DoubleAdder;
12
13			public class DoubleAdderDemo {
14	jsr166	1.2	static final int INCS_PER_THREAD = 10000000;
15	dl	1.1	static final int NCPU = Runtime.getRuntime().availableProcessors();
16			static final ExecutorService pool = Executors.newCachedThreadPool();
17
18			static final class SynchronizedDoubleAdder {
19			double value;
20			synchronized double sum() { return value; }
21			synchronized void add(double x) { value += x; }
22			}
23
24			public static void main(String[] args) {
25			System.out.println("Warmup...");
26			int half = NCPU > 1 ? NCPU / 2 : 1;
27			syncTest(half, 1000);
28			adderTest(half, 1000);
29
30			for (int reps = 0; reps < 2; ++reps) {
31			System.out.println("Running...");
32			for (int i = 1; i <= NCPU * 2; i <<= 1) {
33			syncTest(i, INCS_PER_THREAD);
34			adderTest(i, INCS_PER_THREAD);
35			}
36			}
37			pool.shutdown();
38			}
39
40			static void syncTest(int nthreads, int incs) {
41			System.out.print("Synchronized ");
42			Phaser phaser = new Phaser(nthreads + 1);
43			SynchronizedDoubleAdder a = new SynchronizedDoubleAdder();
44			for (int i = 0; i < nthreads; ++i)
45			pool.execute(new SyncTask(a, phaser, incs));
46			report(nthreads, incs, timeTasks(phaser), a.sum());
47			}
48
49			static void adderTest(int nthreads, int incs) {
50			System.out.print("DoubleAdder ");
51			Phaser phaser = new Phaser(nthreads + 1);
52			DoubleAdder a = new DoubleAdder();
53			for (int i = 0; i < nthreads; ++i)
54			pool.execute(new AdderTask(a, phaser, incs));
55			report(nthreads, incs, timeTasks(phaser), a.sum());
56			}
57
58			static void report(int nthreads, int incs, long time, double sum) {
59			long total = (long)nthreads * incs;
60			if (sum != (double)total)
61			throw new Error(sum + " != " + total);
62			double secs = (double)time / (1000L * 1000 * 1000);
63			long rate = total * (1000L) / time;
64			System.out.printf("threads:%3d Time: %7.3fsec Incs per microsec: %4d\n",
65			nthreads, secs, rate);
66			}
67
68			static long timeTasks(Phaser phaser) {
69			phaser.arriveAndAwaitAdvance();
70			long start = System.nanoTime();
71			phaser.arriveAndAwaitAdvance();
72			phaser.arriveAndAwaitAdvance();
73			return System.nanoTime() - start;
74			}
75
76			static final class AdderTask implements Runnable {
77			final DoubleAdder adder;
78			final Phaser phaser;
79			final int incs;
80			volatile double result;
81	jsr166	1.2	AdderTask(DoubleAdder adder, Phaser phaser, int incs) {
82			this.adder = adder;
83	dl	1.1	this.phaser = phaser;
84			this.incs = incs;
85			}
86
87			public void run() {
88			phaser.arriveAndAwaitAdvance();
89			phaser.arriveAndAwaitAdvance();
90			DoubleAdder a = adder;
91			for (int i = 0; i < incs; ++i)
92			a.add(1.0);
93			result = a.sum();
94			phaser.arrive();
95			}
96			}
97
98			static final class SyncTask implements Runnable {
99			final SynchronizedDoubleAdder adder;
100			final Phaser phaser;
101			final int incs;
102			volatile double result;
103	jsr166	1.2	SyncTask(SynchronizedDoubleAdder adder, Phaser phaser, int incs) {
104			this.adder = adder;
105	dl	1.1	this.phaser = phaser;
106			this.incs = incs;
107			}
108
109			public void run() {
110			phaser.arriveAndAwaitAdvance();
111			phaser.arriveAndAwaitAdvance();
112			SynchronizedDoubleAdder a = adder;
113			for (int i = 0; i < incs; ++i)
114			a.add(1.0);
115			result = a.sum();
116			phaser.arrive();
117			}
118			}
119
120	jsr166	1.2	}