/*
* 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
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/*
* 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 12345
*/
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. Overriden by args[0] for testing.
int count = 1024 * 1024;
final Map<String,String> results = new ConcurrentHashMap<String,String>();
Collection<Queue<Boolean>> concurrentQueues() {
List<Queue<Boolean>> queues = new ArrayList<Queue<Boolean>>();
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<String>(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);
final int adderCount =
Math.max(1, Runtime.getRuntime().availableProcessors() / 4);
final int removerCount =
Math.max(1, Runtime.getRuntime().availableProcessors() / 4);
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<Thread>();
final List<Thread> removers = new ArrayList<Thread>();
final List<Thread> pollers = new ArrayList<Thread>();
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<Thread>();
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);}}};}
}