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 * @summary Checks for missed signals by locking and unlocking each of an array of locks once per thread 38 * @library /test/lib 39 */ 40 41 import static java.util.concurrent.TimeUnit.MILLISECONDS; 42 43 import java.util.concurrent.CyclicBarrier; 44 import java.util.concurrent.ExecutorService; 45 import java.util.concurrent.Executors; 46 import java.util.concurrent.ThreadLocalRandom; 47 import java.util.concurrent.locks.ReentrantLock; 48 import jdk.test.lib.Utils; 49 50 public final class LockOncePerThreadLoops { 51 static final long LONG_DELAY_MS = Utils.adjustTimeout(10_000); 52 static final ExecutorService pool = Executors.newCachedThreadPool(); 53 static boolean print = false; 54 static int nlocks = 20_000; 55 static int nthreads = 20; 56 static int replications = 3; 57 58 public static void main(String[] args) throws Exception { 59 if (args.length > 0) 60 replications = Integer.parseInt(args[0]); 61 62 if (args.length > 1) 63 nlocks = Integer.parseInt(args[1]); 64 65 print = true; 66 67 for (int i = 0; i < replications; ++i) { 68 System.out.print("Iteration: " + i); 69 new ReentrantLockLoop().test(); 70 } 71 pool.shutdown(); 72 if (! pool.awaitTermination(LONG_DELAY_MS, MILLISECONDS)) 73 throw new Error(); 74 } 75 76 static final class ReentrantLockLoop implements Runnable { 77 private int v = ThreadLocalRandom.current().nextInt(); 78 private volatile int result = 17; 79 final ReentrantLock[]locks = new ReentrantLock[nlocks]; 80 81 private final ReentrantLock lock = new ReentrantLock(); 82 private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer(); 83 private final CyclicBarrier barrier; 84 ReentrantLockLoop() { 85 barrier = new CyclicBarrier(nthreads+1, timer); 86 for (int i = 0; i < nlocks; ++i) 87 locks[i] = new ReentrantLock(); 88 } 89 90 final void test() throws Exception { 91 for (int i = 0; i < nthreads; ++i) 92 pool.execute(this); 93 barrier.await(); 94 barrier.await(); 95 if (print) { 96 long time = timer.getTime(); 97 double secs = (double)time / 1000000000.0; 98 System.out.println("\t " + secs + "s run time"); 99 } 100 101 int r = result; 102 if (r == 0) // avoid overoptimization 103 System.out.println("useless result: " + r); 104 } 105 106 public final void run() { 107 try { 108 barrier.await(); 109 int sum = v; 110 int x = 0; 111 for (int i = 0; i < locks.length; ++i) { 112 locks[i].lock(); 113 try { 114 v = x += ~(v - i); 115 } 116 finally { 117 locks[i].unlock(); 118 } 119 // Once in a while, do something more expensive 120 if ((~i & 255) == 0) { 121 sum += LoopHelpers.compute1(LoopHelpers.compute2(x)); 122 } 123 else 124 sum += sum ^ x; 125 } 126 barrier.await(); 127 result += sum; 128 } 129 catch (Exception ex) { 130 return; 131 } 132 } 133 } 134 135 }