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/publicdomain/zero/1.0/ 32 */ 33 34 /* 35 * @test 36 * @bug 4486658 37 * @compile 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 }