1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 */
22
23 /*
24 * This file is available under and governed by the GNU General Public
25 * License version 2 only, as published by the Free Software Foundation.
26 * However, the following notice accompanied the original version of this
27 * file:
28 *
29 * Written by Doug Lea with assistance from members of JCP JSR-166
30 * Expert Group and released to the public domain, as explained at
31 * http://creativecommons.org/licenses/publicdomain
32 */
33
34 /*
35 * @test
36 * @bug 4486658
37 * @compile -source 1.5 LockOncePerThreadLoops.java
38 * @run main/timeout=15000 LockOncePerThreadLoops
39 * @summary Checks for missed signals by locking and unlocking each of an array of locks once per thread
40 */
41
42 import java.util.concurrent.*;
43 import java.util.concurrent.locks.*;
44 import java.util.*;
45
46 public final class LockOncePerThreadLoops {
47 static final ExecutorService pool = Executors.newCachedThreadPool();
48 static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
49 static boolean print = false;
50 static int nlocks = 50000;
51 static int nthreads = 100;
52 static int replications = 5;
53
54 public static void main(String[] args) throws Exception {
55 if (args.length > 0)
56 replications = Integer.parseInt(args[0]);
57
58 if (args.length > 1)
59 nlocks = Integer.parseInt(args[1]);
60
61 print = true;
62
63 for (int i = 0; i < replications; ++i) {
64 System.out.print("Iteration: " + i);
65 new ReentrantLockLoop().test();
66 Thread.sleep(100);
67 }
68 pool.shutdown();
69 if (! pool.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS))
70 throw new Error();
71 }
72
73 static final class ReentrantLockLoop implements Runnable {
74 private int v = rng.next();
75 private volatile int result = 17;
76 final ReentrantLock[]locks = new ReentrantLock[nlocks];
77
78 private final ReentrantLock lock = new ReentrantLock();
79 private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
80 private final CyclicBarrier barrier;
81 ReentrantLockLoop() {
82 barrier = new CyclicBarrier(nthreads+1, timer);
83 for (int i = 0; i < nlocks; ++i)
84 locks[i] = new ReentrantLock();
85 }
86
87 final void test() throws Exception {
88 for (int i = 0; i < nthreads; ++i)
89 pool.execute(this);
90 barrier.await();
91 barrier.await();
92 if (print) {
93 long time = timer.getTime();
94 double secs = (double)(time) / 1000000000.0;
95 System.out.println("\t " + secs + "s run time");
96 }
97
98 int r = result;
99 if (r == 0) // avoid overoptimization
100 System.out.println("useless result: " + r);
101 }
102
103 public final void run() {
104 try {
105 barrier.await();
106 int sum = v;
107 int x = 0;
108 for (int i = 0; i < locks.length; ++i) {
109 locks[i].lock();
110 try {
111 v = x += ~(v - i);
112 }
113 finally {
114 locks[i].unlock();
115 }
116 // Once in a while, do something more expensive
117 if ((~i & 255) == 0) {
118 sum += LoopHelpers.compute1(LoopHelpers.compute2(x));
119 }
120 else
121 sum += sum ^ x;
122 }
123 barrier.await();
124 result += sum;
125 }
126 catch (Exception ie) {
127 return;
128 }
129 }
130 }
131
132 }
--- EOF ---