/*
* 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 4486658 5031862
* @compile -source 1.5 TimeoutLockLoops.java
* @run main TimeoutLockLoops
* @summary Checks for responsiveness of locks to timeouts.
* Runs under the assumption that ITERS computations require more than
* TIMEOUT msecs to complete, which seems to be a safe assumption for
* another decade.
*/
import java.util.concurrent.*;
import java.util.concurrent.locks.*;
import java.util.*;
public final class TimeoutLockLoops {
static final ExecutorService pool = Executors.newCachedThreadPool();
static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
static boolean print = false;
static final int ITERS = Integer.MAX_VALUE;
static final long TIMEOUT = 100;
public static void main(String[] args) throws Exception {
int maxThreads = 100;
if (args.length > 0)
maxThreads = Integer.parseInt(args[0]);
print = true;
for (int i = 1; i <= maxThreads; i += (i+1) >>> 1) {
System.out.print("Threads: " + i);
new ReentrantLockLoop(i).test();
Thread.sleep(10);
}
pool.shutdown();
if (! pool.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS))
throw new Error();
}
static final class ReentrantLockLoop implements Runnable {
private int v = rng.next();
private volatile boolean completed;
private volatile int result = 17;
private final ReentrantLock lock = new ReentrantLock();
private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
private final CyclicBarrier barrier;
private final int nthreads;
ReentrantLockLoop(int nthreads) {
this.nthreads = nthreads;
barrier = new CyclicBarrier(nthreads+1, timer);
}
final void test() throws Exception {
for (int i = 0; i < nthreads; ++i) {
lock.lock();
pool.execute(this);
lock.unlock();
}
barrier.await();
Thread.sleep(TIMEOUT);
while (!lock.tryLock()); // Jam lock
// lock.lock();
barrier.await();
if (print) {
long time = timer.getTime();
double secs = (double)(time) / 1000000000.0;
System.out.println("\t " + secs + "s run time");
}
if (completed)
throw new Error("Some thread completed instead of timing out");
int r = result;
if (r == 0) // avoid overoptimization
System.out.println("useless result: " + r);
}
public final void run() {
try {
barrier.await();
int sum = v;
int x = 17;
int n = ITERS;
final ReentrantLock lock = this.lock;
for (;;) {
if (x != 0) {
if (n-- <= 0)
break;
}
if (!lock.tryLock(TIMEOUT, TimeUnit.MILLISECONDS))
break;
try {
v = x = LoopHelpers.compute1(v);
}
finally {
lock.unlock();
}
sum += LoopHelpers.compute2(x);
}
if (n <= 0)
completed = true;
barrier.await();
result += sum;
}
catch (Exception ex) {
ex.printStackTrace();
return;
}
}
}
}