test/loops/FJPhaserLoops.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.*;
import java.util.concurrent.*;
//import jsr166y.*;

/**
 * Based loosely on Java Grande Forum barrierBench
 */
public class FJPhaserLoops {
    static final int NCPUS = Runtime.getRuntime().availableProcessors();
    static final int FIRST_SIZE =   10000;
    static final int LAST_SIZE  = 1000000;
    /** for time conversion */
    static final long NPS = (1000L * 1000 * 1000);

    static final class PhaserAction extends RecursiveAction {
        final int id;
        final int size;
        final Phaser phaser;
        public PhaserAction(int id, Phaser b, int size) {
            this.id = id;
            this.phaser = b;
            this.size = size;
            phaser.register();
        }

        public void compute() {
            int n = size;
            Phaser b = phaser;
            for (int i = 0; i < n; ++i)
                b.arriveAndAwaitAdvance();
        }
    }

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

        System.out.printf("max %d Threads\n", nthreads);

        for (int k = 2; k <= nthreads; k *= 2) {
            ForkJoinPool pool = new ForkJoinPool(k);

            for (int size = FIRST_SIZE; size <= LAST_SIZE; size *= 10) {
                long startTime = System.nanoTime();

                Phaser phaser = new Phaser();
                final PhaserAction[] actions = new PhaserAction[k];
                for (int i = 0; i < k; ++i) {
                    actions[i] = new PhaserAction(i, phaser, size);
                }

                pool.invoke(new RecursiveAction() {
                        public void compute() { invokeAll(actions); }});

                long elapsed = System.nanoTime() - startTime;
                long bs = (NPS * size) / elapsed;
                System.out.printf("%4d Threads %8d iters: %11d barriers/sec\n",
                                  k, size, bs);
            }
            pool.shutdown();
        }
    }

}
Revision:	1.5
Committed:	Sun Oct 21 06:40:21 2012 UTC (11 years, 6 months ago) by jsr166
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.4:	+1 -2 lines
Log Message:	no blank line between javadoc and corresponding code
#	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	jsr166	1.4	* http://creativecommons.org/publicdomain/zero/1.0/
5	dl	1.1	*/
6
7			import java.util.*;
8			import java.util.concurrent.*;
9			//import jsr166y.*;
10
11	jsr166	1.5	/**
12	dl	1.1	* Based loosely on Java Grande Forum barrierBench
13			*/
14			public class FJPhaserLoops {
15			static final int NCPUS = Runtime.getRuntime().availableProcessors();
16			static final int FIRST_SIZE = 10000;
17			static final int LAST_SIZE = 1000000;
18			/** for time conversion */
19			static final long NPS = (1000L * 1000 * 1000);
20
21			static final class PhaserAction extends RecursiveAction {
22			final int id;
23			final int size;
24			final Phaser phaser;
25			public PhaserAction(int id, Phaser b, int size) {
26			this.id = id;
27			this.phaser = b;
28			this.size = size;
29			phaser.register();
30			}
31
32			public void compute() {
33			int n = size;
34			Phaser b = phaser;
35	jsr166	1.3	for (int i = 0; i < n; ++i)
36	dl	1.1	b.arriveAndAwaitAdvance();
37			}
38			}
39
40			public static void main(String[] args) throws Exception {
41			int nthreads = NCPUS;
42			if (args.length > 0)
43			nthreads = Integer.parseInt(args[0]);
44
45			System.out.printf("max %d Threads\n", nthreads);
46
47			for (int k = 2; k <= nthreads; k *= 2) {
48			ForkJoinPool pool = new ForkJoinPool(k);
49
50			for (int size = FIRST_SIZE; size <= LAST_SIZE; size *= 10) {
51			long startTime = System.nanoTime();
52	jsr166	1.2
53	dl	1.1	Phaser phaser = new Phaser();
54			final PhaserAction[] actions = new PhaserAction[k];
55			for (int i = 0; i < k; ++i) {
56			actions[i] = new PhaserAction(i, phaser, size);
57			}
58	jsr166	1.2
59	dl	1.1	pool.invoke(new RecursiveAction() {
60			public void compute() { invokeAll(actions); }});
61	jsr166	1.2
62	dl	1.1	long elapsed = System.nanoTime() - startTime;
63			long bs = (NPS * size) / elapsed;
64			System.out.printf("%4d Threads %8d iters: %11d barriers/sec\n",
65			k, size, bs);
66			}
67			pool.shutdown();
68			}
69			}
70	jsr166	1.2
71	dl	1.1	}