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/*
* 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 Benchmark that tries to GC-tenure head, followed by
* many add/remove operations.
* @run main GCRetention just-testing
*/
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.WeakReference;
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.PriorityBlockingQueue;
import java.util.LinkedList;
import java.util.PriorityQueue;
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 GCRetention {
boolean benchmarkMode;
int count;
/** No guarantees, but effective in practice. */
static void forceFullGc() {
long timeoutMillis = 1000L;
CountDownLatch finalized = new CountDownLatch(1);
ReferenceQueue<Object> queue = new ReferenceQueue<>();
WeakReference<Object> ref = new WeakReference<>(
new Object() { protected void finalize() { finalized.countDown(); }},
queue);
try {
for (int tries = 3; tries--> 0; ) {
System.gc();
if (finalized.await(timeoutMillis, MILLISECONDS)
&& queue.remove(timeoutMillis) != null
&& ref.get() == null) {
System.runFinalization(); // try to pick up stragglers
return;
}
timeoutMillis *= 4;
}
} catch (InterruptedException unexpected) {
throw new AssertionError("unexpected InterruptedException");
}
throw new AssertionError("failed to do a \"full\" gc");
}
final Map<String,String> results = new ConcurrentHashMap<>();
Collection<Queue<Boolean>> queues() {
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 PriorityBlockingQueue<Boolean>());
queues.add(new PriorityQueue<Boolean>());
queues.add(new LinkedList<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) {
benchmarkMode = ! (args.length > 0 && args[0].equals("just-testing"));
count = benchmarkMode ? 1024 * 1024 : 30;
// Warmup
for (Queue<Boolean> queue : queues())
test(queue);
results.clear();
for (Queue<Boolean> queue : queues())
test(queue);
prettyPrintResults();
}
void test(Queue<Boolean> q) {
long t0 = System.nanoTime();
for (int i = 0; i < count; i++)
check(q.add(Boolean.TRUE));
if (benchmarkMode) forceFullGc();
// forceFullGc();
Boolean x;
while ((x = q.poll()) != null)
equal(x, Boolean.TRUE);
check(q.isEmpty());
for (int i = 0; i < 10 * count; i++) {
for (int k = 0; k < 3; k++)
check(q.add(Boolean.TRUE));
for (int k = 0; k < 3; k++)
if (q.poll() != Boolean.TRUE)
fail();
}
check(q.isEmpty());
String className = q.getClass().getSimpleName();
long elapsed = System.nanoTime() - t0;
int nanos = (int) ((double) elapsed / (10 * 3 * count));
results.put(className, String.valueOf(nanos));
}
//--------------------- 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 GCRetention().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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