test/loops/SpinningTieredPhaserLoops.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 SpinningTieredPhaserLoops {
    static final int NCPUS = Runtime.getRuntime().availableProcessors();
    static final ExecutorService pool = Executors.newCachedThreadPool();
    static final int FIRST_SIZE = 10000;
    static final int LAST_SIZE = 1000000;
    /** for time conversion */
    static final long NPS = (1000L * 1000 * 1000);

    static int tasksPerPhaser = Math.max(NCPUS / 4, 4);

    static void build(Runnable[] actions, int sz, int lo, int hi, Phaser b) {
        if (hi - lo > tasksPerPhaser) {
            for (int i = lo; i < hi; i += tasksPerPhaser) {
                int j = Math.min(i + tasksPerPhaser, hi);
                build(actions, sz, i, j, new Phaser(b));
            }
        } else {
            for (int i = lo; i < hi; ++i)
                actions[i] = new PhaserAction(i, b, sz);
        }
    }

    static final class PhaserAction implements Runnable {
        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 run() {
            int n = size;
            Phaser b = phaser;
            for (int i = 0; i < n; ++i) {
                int p = b.arrive();
                while (b.getPhase() == p) {
                    if ((ThreadLocalRandom.current().nextInt() & 127) == 0)
                        Thread.yield();
                }
            }
        }
    }

    public static void main(String[] args) throws Exception {
        int nthreads = NCPUS;
        if (args.length > 0)
            nthreads = Integer.parseInt(args[0]);
        if (args.length > 1)
            tasksPerPhaser = Integer.parseInt(args[1]);

        System.out.printf("Max %d Threads, %d tasks per phaser\n", nthreads, tasksPerPhaser);

        for (int k = 2; k <= nthreads; k *= 2) {
            for (int size = FIRST_SIZE; size <= LAST_SIZE; size *= 10) {
                long startTime = System.nanoTime();

                Runnable[] actions = new Runnable[k];
                build(actions, size, 0, k, new Phaser());
                Future<?>[] futures = new Future<?>[k];
                for (int i = 0; i < k; ++i) {
                    futures[i] = pool.submit(actions[i]);
                }
                for (int i = 0; i < k; ++i) {
                    futures[i].get();
                }
                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:	1.8
Committed:	Thu Jan 15 18:34:19 2015 UTC (9 years, 3 months ago) by jsr166
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.7:	+0 -1 lines
Log Message:	delete extraneous blank lines
#	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	1.5	* 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	1.6	/**
12	dl	1.1	* Based loosely on Java Grande Forum barrierBench
13			*/
14			public class SpinningTieredPhaserLoops {
15			static final int NCPUS = Runtime.getRuntime().availableProcessors();
16			static final ExecutorService pool = Executors.newCachedThreadPool();
17			static final int FIRST_SIZE = 10000;
18			static final int LAST_SIZE = 1000000;
19			/** for time conversion */
20			static final long NPS = (1000L * 1000 * 1000);
21
22			static int tasksPerPhaser = Math.max(NCPUS / 4, 4);
23	jsr166	1.2
24	dl	1.1	static void build(Runnable[] actions, int sz, int lo, int hi, Phaser b) {
25	dl	1.4	if (hi - lo > tasksPerPhaser) {
26			for (int i = lo; i < hi; i += tasksPerPhaser) {
27			int j = Math.min(i + tasksPerPhaser, hi);
28			build(actions, sz, i, j, new Phaser(b));
29	dl	1.1	}
30	dl	1.4	} else {
31	jsr166	1.2	for (int i = lo; i < hi; ++i)
32	dl	1.1	actions[i] = new PhaserAction(i, b, sz);
33			}
34			}
35
36			static final class PhaserAction implements Runnable {
37			final int id;
38			final int size;
39			final Phaser phaser;
40			public PhaserAction(int id, Phaser b, int size) {
41			this.id = id;
42			this.phaser = b;
43			this.size = size;
44			phaser.register();
45			}
46
47			public void run() {
48			int n = size;
49			Phaser b = phaser;
50	jsr166	1.3	for (int i = 0; i < n; ++i) {
51	dl	1.1	int p = b.arrive();
52			while (b.getPhase() == p) {
53			if ((ThreadLocalRandom.current().nextInt() & 127) == 0)
54			Thread.yield();
55			}
56			}
57			}
58			}
59
60			public static void main(String[] args) throws Exception {
61			int nthreads = NCPUS;
62			if (args.length > 0)
63			nthreads = Integer.parseInt(args[0]);
64			if (args.length > 1)
65			tasksPerPhaser = Integer.parseInt(args[1]);
66	jsr166	1.2
67	dl	1.1	System.out.printf("Max %d Threads, %d tasks per phaser\n", nthreads, tasksPerPhaser);
68
69			for (int k = 2; k <= nthreads; k *= 2) {
70			for (int size = FIRST_SIZE; size <= LAST_SIZE; size *= 10) {
71			long startTime = System.nanoTime();
72	jsr166	1.2
73	jsr166	1.7	Runnable[] actions = new Runnable[k];
74	dl	1.1	build(actions, size, 0, k, new Phaser());
75	jsr166	1.7	Future<?>[] futures = new Future<?>[k];
76	dl	1.1	for (int i = 0; i < k; ++i) {
77			futures[i] = pool.submit(actions[i]);
78			}
79			for (int i = 0; i < k; ++i) {
80			futures[i].get();
81			}
82			long elapsed = System.nanoTime() - startTime;
83			long bs = (NPS * size) / elapsed;
84			System.out.printf("%4d Threads %8d iters: %11d barriers/sec\n",
85			k, size, bs);
86			}
87			}
88			pool.shutdown();
89			}
90	jsr166	1.2
91	dl	1.1	}