| /* |
| * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * 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/ |
| */ |
| |
| /* Adapted from Dougs CVS test/jsr166e/LongAdderDemo.java |
| * |
| * The demo is a micro-benchmark to compare AtomicLong and LongAdder (run |
| * without any args), this restricted version simply exercises the basic |
| * functionality of LongAdder, suitable for automated testing (-shortrun). |
| */ |
| |
| /* |
| * @test |
| * @bug 8005311 |
| * @run main LongAdderDemo -shortrun |
| * @summary Basic test for LongAdder |
| */ |
| |
| import java.util.concurrent.ExecutorService; |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.Phaser; |
| import java.util.concurrent.atomic.AtomicLong; |
| import java.util.concurrent.atomic.LongAdder; |
| |
| public class LongAdderDemo { |
| static final int INCS_PER_THREAD = 10000000; |
| static final int NCPU = Runtime.getRuntime().availableProcessors(); |
| static final int SHORT_RUN_MAX_THREADS = NCPU > 1 ? NCPU / 2 : 1; |
| static final int LONG_RUN_MAX_THREADS = NCPU * 2; |
| static final ExecutorService pool = Executors.newCachedThreadPool(); |
| |
| public static void main(String[] args) { |
| boolean shortRun = args.length > 0 && args[0].equals("-shortrun"); |
| int maxNumThreads = shortRun ? SHORT_RUN_MAX_THREADS : LONG_RUN_MAX_THREADS; |
| |
| System.out.println("Warmup..."); |
| int half = NCPU > 1 ? NCPU / 2 : 1; |
| if (!shortRun) |
| casTest(half, 1000); |
| adderTest(half, 1000); |
| |
| for (int reps = 0; reps < 2; ++reps) { |
| System.out.println("Running..."); |
| for (int i = 1; i <= maxNumThreads; i <<= 1) { |
| if (!shortRun) |
| casTest(i, INCS_PER_THREAD); |
| adderTest(i, INCS_PER_THREAD); |
| } |
| } |
| pool.shutdown(); |
| } |
| |
| static void casTest(int nthreads, int incs) { |
| System.out.print("AtomicLong "); |
| Phaser phaser = new Phaser(nthreads + 1); |
| AtomicLong a = new AtomicLong(); |
| for (int i = 0; i < nthreads; ++i) |
| pool.execute(new CasTask(a, phaser, incs)); |
| report(nthreads, incs, timeTasks(phaser), a.get()); |
| } |
| |
| static void adderTest(int nthreads, int incs) { |
| System.out.print("LongAdder "); |
| Phaser phaser = new Phaser(nthreads + 1); |
| LongAdder a = new LongAdder(); |
| 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, long sum) { |
| long total = (long)nthreads * incs; |
| if (sum != 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 LongAdder adder; |
| final Phaser phaser; |
| final int incs; |
| volatile long result; |
| AdderTask(LongAdder adder, Phaser phaser, int incs) { |
| this.adder = adder; |
| this.phaser = phaser; |
| this.incs = incs; |
| } |
| |
| public void run() { |
| phaser.arriveAndAwaitAdvance(); |
| phaser.arriveAndAwaitAdvance(); |
| LongAdder a = adder; |
| for (int i = 0; i < incs; ++i) |
| a.increment(); |
| result = a.sum(); |
| phaser.arrive(); |
| } |
| } |
| |
| static final class CasTask implements Runnable { |
| final AtomicLong adder; |
| final Phaser phaser; |
| final int incs; |
| volatile long result; |
| CasTask(AtomicLong adder, Phaser phaser, int incs) { |
| this.adder = adder; |
| this.phaser = phaser; |
| this.incs = incs; |
| } |
| |
| public void run() { |
| phaser.arriveAndAwaitAdvance(); |
| phaser.arriveAndAwaitAdvance(); |
| AtomicLong a = adder; |
| for (int i = 0; i < incs; ++i) |
| a.getAndIncrement(); |
| result = a.get(); |
| phaser.arrive(); |
| } |
| } |
| |
| } |