| /* |
| * 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 6785442 |
| * @summary Checks race between poll and remove(Object), while |
| * occasionally moonlighting as a microbenchmark. |
| * @run main RemovePollRace 1234 |
| */ |
| |
| import java.util.concurrent.ArrayBlockingQueue; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.concurrent.ConcurrentLinkedDeque; |
| import java.util.concurrent.ConcurrentLinkedQueue; |
| import java.util.concurrent.CountDownLatch; |
| import java.util.concurrent.LinkedBlockingDeque; |
| import java.util.concurrent.LinkedBlockingQueue; |
| import java.util.concurrent.LinkedTransferQueue; |
| import java.util.concurrent.atomic.AtomicLong; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Queue; |
| import java.util.Map; |
| |
| public class RemovePollRace { |
| // Suitable for benchmarking. Overridden by args[0] for testing. |
| int count = 1024 * 1024; |
| |
| final Map<String,String> results = new ConcurrentHashMap<>(); |
| |
| Collection<Queue<Boolean>> concurrentQueues() { |
| List<Queue<Boolean>> queues = new ArrayList<>(); |
| queues.add(new ConcurrentLinkedDeque<Boolean>()); |
| queues.add(new ConcurrentLinkedQueue<Boolean>()); |
| queues.add(new ArrayBlockingQueue<Boolean>(count, false)); |
| queues.add(new ArrayBlockingQueue<Boolean>(count, true)); |
| queues.add(new LinkedBlockingQueue<Boolean>()); |
| queues.add(new LinkedBlockingDeque<Boolean>()); |
| queues.add(new LinkedTransferQueue<Boolean>()); |
| |
| // Following additional implementations are available from: |
| // http://gee.cs.oswego.edu/dl/concurrency-interest/index.html |
| // queues.add(new SynchronizedLinkedListQueue<Boolean>()); |
| |
| // Avoid "first fast, second slow" benchmark effect. |
| Collections.shuffle(queues); |
| return queues; |
| } |
| |
| void prettyPrintResults() { |
| List<String> classNames = new ArrayList<>(results.keySet()); |
| Collections.sort(classNames); |
| int maxClassNameLength = 0; |
| int maxNanosLength = 0; |
| for (String name : classNames) { |
| if (maxClassNameLength < name.length()) |
| maxClassNameLength = name.length(); |
| if (maxNanosLength < results.get(name).length()) |
| maxNanosLength = results.get(name).length(); |
| } |
| String format = String.format("%%%ds %%%ds nanos/item%%n", |
| maxClassNameLength, maxNanosLength); |
| for (String name : classNames) |
| System.out.printf(format, name, results.get(name)); |
| } |
| |
| void test(String[] args) throws Throwable { |
| if (args.length > 0) |
| count = Integer.valueOf(args[0]); |
| |
| // Warmup |
| for (Queue<Boolean> queue : concurrentQueues()) |
| test(queue); |
| results.clear(); |
| for (Queue<Boolean> queue : concurrentQueues()) |
| test(queue); |
| |
| prettyPrintResults(); |
| } |
| |
| void await(CountDownLatch latch) { |
| try { latch.await(); } |
| catch (InterruptedException e) { unexpected(e); } |
| } |
| |
| void test(final Queue<Boolean> q) throws Throwable { |
| long t0 = System.nanoTime(); |
| final int SPINS = 5; |
| final AtomicLong removes = new AtomicLong(0); |
| final AtomicLong polls = new AtomicLong(0); |
| |
| // We need at least 3 threads, but we don't want to use too |
| // many on massively multi-core systems. |
| final int cpus = Runtime.getRuntime().availableProcessors(); |
| final int threadsToUse = Math.max(3, Math.min(cpus, 16)); |
| final int adderCount = threadsToUse / 3; |
| final int removerCount = adderCount; |
| final int pollerCount = removerCount; |
| final int threadCount = adderCount + removerCount + pollerCount; |
| |
| final CountDownLatch startingGate = new CountDownLatch(1); |
| final CountDownLatch addersDone = new CountDownLatch(adderCount); |
| final Runnable remover = new Runnable() { |
| public void run() { |
| await(startingGate); |
| int spins = 0; |
| for (;;) { |
| boolean quittingTime = (addersDone.getCount() == 0); |
| if (q.remove(Boolean.TRUE)) |
| removes.getAndIncrement(); |
| else if (quittingTime) |
| break; |
| else if (++spins > SPINS) { |
| Thread.yield(); |
| spins = 0; |
| }}}}; |
| final Runnable poller = new Runnable() { |
| public void run() { |
| await(startingGate); |
| int spins = 0; |
| for (;;) { |
| boolean quittingTime = (addersDone.getCount() == 0); |
| if (q.poll() == Boolean.TRUE) |
| polls.getAndIncrement(); |
| else if (quittingTime) |
| break; |
| else if (++spins > SPINS) { |
| Thread.yield(); |
| spins = 0; |
| }}}}; |
| final Runnable adder = new Runnable() { |
| public void run() { |
| await(startingGate); |
| for (int i = 0; i < count; i++) { |
| for (;;) { |
| try { q.add(Boolean.TRUE); break; } |
| catch (IllegalStateException e) { Thread.yield(); } |
| } |
| } |
| addersDone.countDown(); |
| }}; |
| |
| final List<Thread> adders = new ArrayList<>(); |
| final List<Thread> removers = new ArrayList<>(); |
| final List<Thread> pollers = new ArrayList<>(); |
| for (int i = 0; i < adderCount; i++) |
| adders.add(checkedThread(adder)); |
| for (int i = 0; i < removerCount; i++) |
| removers.add(checkedThread(remover)); |
| for (int i = 0; i < pollerCount; i++) |
| pollers.add(checkedThread(poller)); |
| |
| final List<Thread> allThreads = new ArrayList<>(); |
| allThreads.addAll(removers); |
| allThreads.addAll(pollers); |
| allThreads.addAll(adders); |
| |
| for (Thread t : allThreads) |
| t.start(); |
| startingGate.countDown(); |
| for (Thread t : allThreads) |
| t.join(); |
| |
| String className = q.getClass().getSimpleName(); |
| long elapsed = System.nanoTime() - t0; |
| int nanos = (int) ((double) elapsed / (adderCount * count)); |
| results.put(className, String.valueOf(nanos)); |
| if (removes.get() + polls.get() != adderCount * count) { |
| String msg = String.format |
| ("class=%s removes=%s polls=%d count=%d", |
| className, removes.get(), polls.get(), count); |
| fail(msg); |
| } |
| } |
| |
| //--------------------- Infrastructure --------------------------- |
| volatile int passed = 0, failed = 0; |
| void pass() {passed++;} |
| void fail() {failed++; Thread.dumpStack();} |
| void fail(String msg) {System.err.println(msg); fail();} |
| void unexpected(Throwable t) {failed++; t.printStackTrace();} |
| void check(boolean cond) {if (cond) pass(); else fail();} |
| void equal(Object x, Object y) { |
| if (x == null ? y == null : x.equals(y)) pass(); |
| else fail(x + " not equal to " + y);} |
| public static void main(String[] args) throws Throwable { |
| new RemovePollRace().instanceMain(args);} |
| public void instanceMain(String[] args) throws Throwable { |
| try {test(args);} catch (Throwable t) {unexpected(t);} |
| System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed); |
| if (failed > 0) throw new AssertionError("Some tests failed");} |
| Thread checkedThread(final Runnable r) { |
| return new Thread() {public void run() { |
| try {r.run();} catch (Throwable t) {unexpected(t);}}};} |
| } |