| /* |
| * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| */ |
| |
| /* |
| * This file is available under and governed by the GNU General Public |
| * License version 2 only, as published by the Free Software Foundation. |
| * However, the following notice accompanied the original version of this |
| * file: |
| * |
| * 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 |
| */ |
| |
| /* |
| * @test |
| * @bug 4486658 |
| * @compile -source 1.5 ConcurrentQueueLoops.java |
| * @run main/timeout=230 ConcurrentQueueLoops |
| * @summary Checks that a set of threads can repeatedly get and modify items |
| */ |
| |
| import java.util.*; |
| import java.util.concurrent.*; |
| import java.util.concurrent.atomic.*; |
| |
| public class ConcurrentQueueLoops { |
| static final ExecutorService pool = Executors.newCachedThreadPool(); |
| static AtomicInteger totalItems; |
| static boolean print = false; |
| |
| public static void main(String[] args) throws Exception { |
| int maxStages = 8; |
| int items = 100000; |
| |
| if (args.length > 0) |
| maxStages = Integer.parseInt(args[0]); |
| |
| print = false; |
| System.out.println("Warmup..."); |
| oneRun(1, items); |
| Thread.sleep(100); |
| oneRun(1, items); |
| Thread.sleep(100); |
| print = true; |
| |
| for (int i = 1; i <= maxStages; i += (i+1) >>> 1) { |
| oneRun(i, items); |
| } |
| pool.shutdown(); |
| if (! pool.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS)) |
| throw new Error(); |
| } |
| |
| static class Stage implements Callable<Integer> { |
| final Queue<Integer> queue; |
| final CyclicBarrier barrier; |
| int items; |
| Stage (Queue<Integer> q, CyclicBarrier b, int items) { |
| queue = q; |
| barrier = b; |
| this.items = items; |
| } |
| |
| public Integer call() { |
| // Repeatedly take something from queue if possible, |
| // transform it, and put back in. |
| try { |
| barrier.await(); |
| int l = 4321; |
| int takes = 0; |
| for (;;) { |
| Integer item = queue.poll(); |
| if (item != null) { |
| ++takes; |
| l = LoopHelpers.compute2(item.intValue()); |
| } |
| else if (takes != 0) { |
| totalItems.getAndAdd(-takes); |
| takes = 0; |
| } |
| else if (totalItems.get() <= 0) |
| break; |
| l = LoopHelpers.compute1(l); |
| if (items > 0) { |
| --items; |
| queue.offer(new Integer(l)); |
| } |
| else if ( (l & (3 << 5)) == 0) // spinwait |
| Thread.sleep(1); |
| } |
| return new Integer(l); |
| } |
| catch (Exception ie) { |
| ie.printStackTrace(); |
| throw new Error("Call loop failed"); |
| } |
| } |
| } |
| |
| static void oneRun(int n, int items) throws Exception { |
| Queue<Integer> q = new ConcurrentLinkedQueue<Integer>(); |
| LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer(); |
| CyclicBarrier barrier = new CyclicBarrier(n + 1, timer); |
| totalItems = new AtomicInteger(n * items); |
| ArrayList<Future<Integer>> results = new ArrayList<Future<Integer>>(n); |
| for (int i = 0; i < n; ++i) |
| results.add(pool.submit(new Stage(q, barrier, items))); |
| |
| if (print) |
| System.out.print("Threads: " + n + "\t:"); |
| barrier.await(); |
| int total = 0; |
| for (int i = 0; i < n; ++i) { |
| Future<Integer> f = results.get(i); |
| Integer r = f.get(); |
| total += r.intValue(); |
| } |
| long endTime = System.nanoTime(); |
| long time = endTime - timer.startTime; |
| if (print) |
| System.out.println(LoopHelpers.rightJustify(time / (items * n)) + " ns per item"); |
| if (total == 0) // avoid overoptimization |
| System.out.println("useless result: " + total); |
| |
| } |
| } |