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
#	Content
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	static final int INCS_PER_THREAD = 10000000;
15	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	AdderTask(DoubleAdder adder, Phaser phaser, int incs) {
82	this.adder = adder;
83	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	SyncTask(SynchronizedDoubleAdder adder, Phaser phaser, int incs) {
104	this.adder = adder;
105	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	}