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/licenses/publicdomain
 */

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) {
        int step = (hi - lo) / tasksPerPhaser;
        if (step > 1) {
            int i = lo;
            while (i < hi) {
                int r = Math.min(i + step, hi);
                build(actions, sz, i, r, new Phaser(b));
                i = r;
            }
        }
        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:	1.2
Committed:	Mon Nov 2 20:23:53 2009 UTC (14 years, 6 months ago) by jsr166
Branch:	MAIN
Changes since 1.1:	+5 -7 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/licenses/publicdomain
5			*/
6
7			import java.util.*;
8			import java.util.concurrent.*;
9			//import jsr166y.*;
10
11			/*
12			* Based loosely on Java Grande Forum barrierBench
13			*/
14
15			public class SpinningTieredPhaserLoops {
16			static final int NCPUS = Runtime.getRuntime().availableProcessors();
17			static final ExecutorService pool = Executors.newCachedThreadPool();
18			static final int FIRST_SIZE = 10000;
19			static final int LAST_SIZE = 1000000;
20			/** for time conversion */
21			static final long NPS = (1000L * 1000 * 1000);
22
23			static int tasksPerPhaser = Math.max(NCPUS / 4, 4);
24	jsr166	1.2
25	dl	1.1	static void build(Runnable[] actions, int sz, int lo, int hi, Phaser b) {
26			int step = (hi - lo) / tasksPerPhaser;
27			if (step > 1) {
28			int i = lo;
29			while (i < hi) {
30			int r = Math.min(i + step, hi);
31			build(actions, sz, i, r, new Phaser(b));
32			i = r;
33			}
34			}
35			else {
36	jsr166	1.2	for (int i = lo; i < hi; ++i)
37	dl	1.1	actions[i] = new PhaserAction(i, b, sz);
38			}
39			}
40
41			static final class PhaserAction implements Runnable {
42			final int id;
43			final int size;
44			final Phaser phaser;
45			public PhaserAction(int id, Phaser b, int size) {
46			this.id = id;
47			this.phaser = b;
48			this.size = size;
49			phaser.register();
50			}
51
52
53			public void run() {
54			int n = size;
55			Phaser b = phaser;
56			for(int i = 0; i < n; ++i) {
57			int p = b.arrive();
58			while (b.getPhase() == p) {
59			if ((ThreadLocalRandom.current().nextInt() & 127) == 0)
60			Thread.yield();
61			}
62			}
63			}
64			}
65
66			public static void main(String[] args) throws Exception {
67			int nthreads = NCPUS;
68			if (args.length > 0)
69			nthreads = Integer.parseInt(args[0]);
70			if (args.length > 1)
71			tasksPerPhaser = Integer.parseInt(args[1]);
72	jsr166	1.2
73	dl	1.1	System.out.printf("Max %d Threads, %d tasks per phaser\n", nthreads, tasksPerPhaser);
74
75			for (int k = 2; k <= nthreads; k *= 2) {
76			for (int size = FIRST_SIZE; size <= LAST_SIZE; size *= 10) {
77			long startTime = System.nanoTime();
78	jsr166	1.2
79	dl	1.1	Runnable[] actions = new Runnable [k];
80			build(actions, size, 0, k, new Phaser());
81			Future[] futures = new Future[k];
82			for (int i = 0; i < k; ++i) {
83			futures[i] = pool.submit(actions[i]);
84			}
85			for (int i = 0; i < k; ++i) {
86			futures[i].get();
87			}
88			long elapsed = System.nanoTime() - startTime;
89			long bs = (NPS * size) / elapsed;
90			System.out.printf("%4d Threads %8d iters: %11d barriers/sec\n",
91			k, size, bs);
92			}
93			}
94			pool.shutdown();
95			}
96	jsr166	1.2
97	dl	1.1	}