| /* |
| * 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. |
| */ |
| |
| /* |
| * 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/publicdomain/zero/1.0/ |
| */ |
| |
| /* |
| * @test |
| * @bug 4486658 |
| * @summary checks to make sure a pipeline of exchangers passes data. |
| * @library /lib/testlibrary/ |
| */ |
| |
| import static java.util.concurrent.TimeUnit.MILLISECONDS; |
| |
| import java.util.concurrent.CyclicBarrier; |
| import java.util.concurrent.Exchanger; |
| import java.util.concurrent.ExecutorService; |
| import java.util.concurrent.Executors; |
| import jdk.testlibrary.Utils; |
| |
| public class ExchangeLoops { |
| static final long LONG_DELAY_MS = Utils.adjustTimeout(10_000); |
| static final ExecutorService pool = Executors.newCachedThreadPool(); |
| static boolean print = false; |
| |
| static class Int { |
| public int value; |
| Int(int i) { value = i; } |
| } |
| |
| public static void main(String[] args) throws Exception { |
| int maxStages = 5; |
| int iters = 2000; |
| |
| if (args.length > 0) |
| maxStages = Integer.parseInt(args[0]); |
| |
| print = false; |
| System.out.println("Warmup..."); |
| oneRun(2, iters); |
| print = true; |
| |
| for (int i = 2; i <= maxStages; i += (i+1) >>> 1) { |
| System.out.print("Threads: " + i + "\t: "); |
| oneRun(i, iters); |
| } |
| pool.shutdown(); |
| if (! pool.awaitTermination(LONG_DELAY_MS, MILLISECONDS)) |
| throw new Error(); |
| } |
| |
| static class Stage implements Runnable { |
| final int iters; |
| final Exchanger<Int> left; |
| final Exchanger<Int> right; |
| final CyclicBarrier barrier; |
| volatile int result; |
| Stage(Exchanger<Int> left, |
| Exchanger<Int> right, |
| CyclicBarrier b, int iters) { |
| this.left = left; |
| this.right = right; |
| barrier = b; |
| this.iters = iters; |
| } |
| |
| public void run() { |
| try { |
| barrier.await(); |
| Int item = new Int(hashCode()); |
| for (int i = 0; i < iters; ++i) { |
| if (left != null) { |
| item.value = LoopHelpers.compute1(item.value); |
| Int other = left.exchange(item); |
| if (other == item || other == null) |
| throw new Error("Failed Exchange"); |
| item = other; |
| |
| } |
| if (right != null) { |
| item.value = LoopHelpers.compute2(item.value); |
| Int other = right.exchange(item); |
| if (other == item || other == null) |
| throw new Error("Failed Exchange"); |
| item = other; |
| } |
| } |
| barrier.await(); |
| |
| } |
| catch (Exception ex) { |
| ex.printStackTrace(); |
| return; |
| } |
| } |
| } |
| |
| static void oneRun(int nthreads, int iters) throws Exception { |
| LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer(); |
| CyclicBarrier barrier = new CyclicBarrier(nthreads + 1, timer); |
| Exchanger<Int> l = null; |
| Exchanger<Int> r = new Exchanger<>(); |
| for (int i = 0; i < nthreads; ++i) { |
| pool.execute(new Stage(l, r, barrier, iters)); |
| l = r; |
| r = (i+2 < nthreads) ? new Exchanger<Int>() : null; |
| } |
| barrier.await(); |
| barrier.await(); |
| long time = timer.getTime(); |
| if (print) |
| System.out.println(LoopHelpers.rightJustify(time / (iters * nthreads + iters * (nthreads-2))) + " ns per transfer"); |
| } |
| |
| } |