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 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:	1.3
Committed:	Thu Feb 26 06:53:34 2015 UTC (9 years, 2 months ago) by jsr166
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.2:	+0 -1 lines
Log Message:	delete unused imports
#	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 jsr166e.DoubleAdder;
11
12	public class DoubleAdderDemo {
13	static final int INCS_PER_THREAD = 10000000;
14	static final int NCPU = Runtime.getRuntime().availableProcessors();
15	static final ExecutorService pool = Executors.newCachedThreadPool();
16
17	static final class SynchronizedDoubleAdder {
18	double value;
19	synchronized double sum() { return value; }
20	synchronized void add(double x) { value += x; }
21	}
22
23	public static void main(String[] args) {
24	System.out.println("Warmup...");
25	int half = NCPU > 1 ? NCPU / 2 : 1;
26	syncTest(half, 1000);
27	adderTest(half, 1000);
28
29	for (int reps = 0; reps < 2; ++reps) {
30	System.out.println("Running...");
31	for (int i = 1; i <= NCPU * 2; i <<= 1) {
32	syncTest(i, INCS_PER_THREAD);
33	adderTest(i, INCS_PER_THREAD);
34	}
35	}
36	pool.shutdown();
37	}
38
39	static void syncTest(int nthreads, int incs) {
40	System.out.print("Synchronized ");
41	Phaser phaser = new Phaser(nthreads + 1);
42	SynchronizedDoubleAdder a = new SynchronizedDoubleAdder();
43	for (int i = 0; i < nthreads; ++i)
44	pool.execute(new SyncTask(a, phaser, incs));
45	report(nthreads, incs, timeTasks(phaser), a.sum());
46	}
47
48	static void adderTest(int nthreads, int incs) {
49	System.out.print("DoubleAdder ");
50	Phaser phaser = new Phaser(nthreads + 1);
51	DoubleAdder a = new DoubleAdder();
52	for (int i = 0; i < nthreads; ++i)
53	pool.execute(new AdderTask(a, phaser, incs));
54	report(nthreads, incs, timeTasks(phaser), a.sum());
55	}
56
57	static void report(int nthreads, int incs, long time, double sum) {
58	long total = (long)nthreads * incs;
59	if (sum != (double)total)
60	throw new Error(sum + " != " + total);
61	double secs = (double)time / (1000L * 1000 * 1000);
62	long rate = total * (1000L) / time;
63	System.out.printf("threads:%3d Time: %7.3fsec Incs per microsec: %4d\n",
64	nthreads, secs, rate);
65	}
66
67	static long timeTasks(Phaser phaser) {
68	phaser.arriveAndAwaitAdvance();
69	long start = System.nanoTime();
70	phaser.arriveAndAwaitAdvance();
71	phaser.arriveAndAwaitAdvance();
72	return System.nanoTime() - start;
73	}
74
75	static final class AdderTask implements Runnable {
76	final DoubleAdder adder;
77	final Phaser phaser;
78	final int incs;
79	volatile double result;
80	AdderTask(DoubleAdder adder, Phaser phaser, int incs) {
81	this.adder = adder;
82	this.phaser = phaser;
83	this.incs = incs;
84	}
85
86	public void run() {
87	phaser.arriveAndAwaitAdvance();
88	phaser.arriveAndAwaitAdvance();
89	DoubleAdder a = adder;
90	for (int i = 0; i < incs; ++i)
91	a.add(1.0);
92	result = a.sum();
93	phaser.arrive();
94	}
95	}
96
97	static final class SyncTask implements Runnable {
98	final SynchronizedDoubleAdder adder;
99	final Phaser phaser;
100	final int incs;
101	volatile double result;
102	SyncTask(SynchronizedDoubleAdder adder, Phaser phaser, int incs) {
103	this.adder = adder;
104	this.phaser = phaser;
105	this.incs = incs;
106	}
107
108	public void run() {
109	phaser.arriveAndAwaitAdvance();
110	phaser.arriveAndAwaitAdvance();
111	SynchronizedDoubleAdder a = adder;
112	for (int i = 0; i < incs; ++i)
113	a.add(1.0);
114	result = a.sum();
115	phaser.arrive();
116	}
117	}
118
119	}