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Java example source code file (ConcurrentQueueLoops.java)
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The ConcurrentQueueLoops.java Java example source code
/*
* 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 6785442
* @run main ConcurrentQueueLoops 8 123456
* @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 {
ExecutorService pool;
AtomicInteger totalItems;
boolean print;
// Suitable for benchmarking. Overriden by args[0] for testing.
int maxStages = 20;
// Suitable for benchmarking. Overriden by args[1] for testing.
int items = 1024 * 1024;
Collection<Queue concurrentQueues() {
List<Queue queues = new ArrayList>();
queues.add(new ConcurrentLinkedDeque<Integer>());
queues.add(new ConcurrentLinkedQueue<Integer>());
queues.add(new ArrayBlockingQueue<Integer>(items, false));
//queues.add(new ArrayBlockingQueue<Integer>(count, true));
queues.add(new LinkedBlockingQueue<Integer>());
queues.add(new LinkedBlockingDeque<Integer>());
queues.add(new LinkedTransferQueue<Integer>());
// Following additional implementations are available from:
// http://gee.cs.oswego.edu/dl/concurrency-interest/index.html
// queues.add(new SynchronizedLinkedListQueue<Integer>());
// Avoid "first fast, second slow" benchmark effect.
Collections.shuffle(queues);
return queues;
}
void test(String[] args) throws Throwable {
if (args.length > 0)
maxStages = Integer.parseInt(args[0]);
if (args.length > 1)
items = Integer.parseInt(args[1]);
for (Queue<Integer> queue : concurrentQueues())
test(queue);
}
void test(final Queue<Integer> q) throws Throwable {
System.out.println(q.getClass().getSimpleName());
pool = Executors.newCachedThreadPool();
print = false;
print = false;
System.out.println("Warmup...");
oneRun(1, items, q);
//Thread.sleep(100);
oneRun(3, items, q);
Thread.sleep(100);
print = true;
for (int i = 1; i <= maxStages; i += (i+1) >>> 1) {
oneRun(i, items, q);
}
pool.shutdown();
check(pool.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS));
}
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 (Throwable t) { unexpected(t); return null; }
}
}
void oneRun(int n, int items, final Queue<Integer> q) throws Exception {
LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
CyclicBarrier barrier = new CyclicBarrier(n + 1, timer);
totalItems = new AtomicInteger(n * items);
ArrayList<Future results = new ArrayList>(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);
}
//--------------------- 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 ConcurrentQueueLoops().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");}
}
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