229 lines
9.0 KiB
Java
229 lines
9.0 KiB
Java
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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* This file is available under and governed by the GNU General Public
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* License version 2 only, as published by the Free Software Foundation.
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* However, the following notice accompanied the original version of this
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* file:
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*
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* Written by Doug Lea with assistance from members of JCP JSR-166
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* Expert Group and released to the public domain, as explained at
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* http://creativecommons.org/publicdomain/zero/1.0/
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*/
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/*
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* @test
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* @bug 6785442
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* @summary Checks race between poll and remove(Object), while
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* occasionally moonlighting as a microbenchmark.
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* @run main RemovePollRace 1234
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*/
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import java.util.concurrent.ArrayBlockingQueue;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.concurrent.ConcurrentLinkedDeque;
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import java.util.concurrent.ConcurrentLinkedQueue;
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import java.util.concurrent.CountDownLatch;
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import java.util.concurrent.LinkedBlockingDeque;
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import java.util.concurrent.LinkedBlockingQueue;
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import java.util.concurrent.LinkedTransferQueue;
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import java.util.concurrent.atomic.AtomicLong;
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import java.util.ArrayList;
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import java.util.Collection;
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import java.util.Collections;
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import java.util.List;
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import java.util.Queue;
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import java.util.Map;
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public class RemovePollRace {
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// Suitable for benchmarking. Overridden by args[0] for testing.
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int count = 1024 * 1024;
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final Map<String,String> results = new ConcurrentHashMap<>();
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Collection<Queue<Boolean>> concurrentQueues() {
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List<Queue<Boolean>> queues = new ArrayList<>();
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queues.add(new ConcurrentLinkedDeque<Boolean>());
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queues.add(new ConcurrentLinkedQueue<Boolean>());
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queues.add(new ArrayBlockingQueue<Boolean>(count, false));
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queues.add(new ArrayBlockingQueue<Boolean>(count, true));
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queues.add(new LinkedBlockingQueue<Boolean>());
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queues.add(new LinkedBlockingDeque<Boolean>());
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queues.add(new LinkedTransferQueue<Boolean>());
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// Following additional implementations are available from:
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// http://gee.cs.oswego.edu/dl/concurrency-interest/index.html
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// queues.add(new SynchronizedLinkedListQueue<Boolean>());
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// Avoid "first fast, second slow" benchmark effect.
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Collections.shuffle(queues);
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return queues;
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}
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void prettyPrintResults() {
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List<String> classNames = new ArrayList<>(results.keySet());
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Collections.sort(classNames);
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int maxClassNameLength = 0;
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int maxNanosLength = 0;
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for (String name : classNames) {
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if (maxClassNameLength < name.length())
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maxClassNameLength = name.length();
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if (maxNanosLength < results.get(name).length())
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maxNanosLength = results.get(name).length();
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}
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String format = String.format("%%%ds %%%ds nanos/item%%n",
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maxClassNameLength, maxNanosLength);
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for (String name : classNames)
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System.out.printf(format, name, results.get(name));
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}
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void test(String[] args) throws Throwable {
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if (args.length > 0)
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count = Integer.valueOf(args[0]);
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// Warmup
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for (Queue<Boolean> queue : concurrentQueues())
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test(queue);
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results.clear();
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for (Queue<Boolean> queue : concurrentQueues())
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test(queue);
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prettyPrintResults();
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}
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void await(CountDownLatch latch) {
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try { latch.await(); }
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catch (InterruptedException e) { unexpected(e); }
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}
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void test(final Queue<Boolean> q) throws Throwable {
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long t0 = System.nanoTime();
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final int SPINS = 5;
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final AtomicLong removes = new AtomicLong(0);
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final AtomicLong polls = new AtomicLong(0);
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// We need at least 3 threads, but we don't want to use too
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// many on massively multi-core systems.
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final int cpus = Runtime.getRuntime().availableProcessors();
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final int threadsToUse = Math.max(3, Math.min(cpus, 16));
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final int adderCount = threadsToUse / 3;
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final int removerCount = adderCount;
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final int pollerCount = removerCount;
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final int threadCount = adderCount + removerCount + pollerCount;
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final CountDownLatch startingGate = new CountDownLatch(1);
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final CountDownLatch addersDone = new CountDownLatch(adderCount);
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final Runnable remover = new Runnable() {
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public void run() {
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await(startingGate);
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int spins = 0;
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for (;;) {
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boolean quittingTime = (addersDone.getCount() == 0);
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if (q.remove(Boolean.TRUE))
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removes.getAndIncrement();
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else if (quittingTime)
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break;
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else if (++spins > SPINS) {
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Thread.yield();
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spins = 0;
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}}}};
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final Runnable poller = new Runnable() {
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public void run() {
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await(startingGate);
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int spins = 0;
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for (;;) {
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boolean quittingTime = (addersDone.getCount() == 0);
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if (q.poll() == Boolean.TRUE)
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polls.getAndIncrement();
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else if (quittingTime)
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break;
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else if (++spins > SPINS) {
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Thread.yield();
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spins = 0;
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}}}};
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final Runnable adder = new Runnable() {
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public void run() {
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await(startingGate);
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for (int i = 0; i < count; i++) {
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for (;;) {
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try { q.add(Boolean.TRUE); break; }
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catch (IllegalStateException e) { Thread.yield(); }
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}
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}
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addersDone.countDown();
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}};
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final List<Thread> adders = new ArrayList<>();
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final List<Thread> removers = new ArrayList<>();
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final List<Thread> pollers = new ArrayList<>();
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for (int i = 0; i < adderCount; i++)
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adders.add(checkedThread(adder));
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for (int i = 0; i < removerCount; i++)
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removers.add(checkedThread(remover));
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for (int i = 0; i < pollerCount; i++)
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pollers.add(checkedThread(poller));
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final List<Thread> allThreads = new ArrayList<>();
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allThreads.addAll(removers);
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allThreads.addAll(pollers);
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allThreads.addAll(adders);
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for (Thread t : allThreads)
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t.start();
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startingGate.countDown();
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for (Thread t : allThreads)
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t.join();
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String className = q.getClass().getSimpleName();
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long elapsed = System.nanoTime() - t0;
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int nanos = (int) ((double) elapsed / (adderCount * count));
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results.put(className, String.valueOf(nanos));
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if (removes.get() + polls.get() != adderCount * count) {
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String msg = String.format
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("class=%s removes=%s polls=%d count=%d",
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className, removes.get(), polls.get(), count);
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fail(msg);
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}
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}
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//--------------------- Infrastructure ---------------------------
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volatile int passed = 0, failed = 0;
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void pass() {passed++;}
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void fail() {failed++; Thread.dumpStack();}
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void fail(String msg) {System.err.println(msg); fail();}
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void unexpected(Throwable t) {failed++; t.printStackTrace();}
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void check(boolean cond) {if (cond) pass(); else fail();}
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void equal(Object x, Object y) {
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if (x == null ? y == null : x.equals(y)) pass();
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else fail(x + " not equal to " + y);}
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public static void main(String[] args) throws Throwable {
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new RemovePollRace().instanceMain(args);}
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public void instanceMain(String[] args) throws Throwable {
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try {test(args);} catch (Throwable t) {unexpected(t);}
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System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
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if (failed > 0) throw new AssertionError("Some tests failed");}
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Thread checkedThread(final Runnable r) {
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return new Thread() {public void run() {
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try {r.run();} catch (Throwable t) {unexpected(t);}}};}
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}
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