1 /* 2 * Copyright (c) 2014, 2019, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 package org.openjdk.bench.vm.lang; 24 25 import org.openjdk.jmh.annotations.Benchmark; 26 import org.openjdk.jmh.annotations.BenchmarkMode; 27 import org.openjdk.jmh.annotations.Mode; 28 import org.openjdk.jmh.annotations.OutputTimeUnit; 29 import org.openjdk.jmh.annotations.Param; 30 import org.openjdk.jmh.annotations.Scope; 31 import org.openjdk.jmh.annotations.Setup; 32 import org.openjdk.jmh.annotations.State; 33 import org.openjdk.jmh.annotations.Threads; 34 35 import java.util.concurrent.TimeUnit; 36 37 38 /** 39 * Benchmark class for simple lock unlock tests. Nothing big should ever go into this class. 40 */ 41 @BenchmarkMode(Mode.AverageTime) 42 @OutputTimeUnit(TimeUnit.NANOSECONDS) 43 @State(Scope.Benchmark) 44 public class LockUnlock { 45 46 @Param("100") 47 private int innerCount; 48 49 public Object lockObject1; 50 public Object lockObject2; 51 public int factorial; 52 public int dummyInt1; 53 public int dummyInt2; 54 55 @Setup 56 public void setup() { 57 lockObject1 = new Object(); 58 lockObject2 = new Object(); 59 dummyInt1 = 47; 60 dummyInt2 = 11; // anything 61 } 62 63 /** Perform a synchronized on a local object within a loop. */ 64 @Benchmark 65 public void testSimpleLockUnlock() { 66 Object localObject = lockObject1; 67 for (int i = 0; i < innerCount; i++) { 68 synchronized (localObject) { 69 dummyInt1++; 70 dummyInt2++; 71 } 72 } 73 } 74 75 /** Perform a recursive synchronized on a local object within a loop. */ 76 @Benchmark 77 public void testRecursiveLockUnlock() { 78 Object localObject = lockObject1; 79 for (int i = 0; i < innerCount; i++) { 80 synchronized (localObject) { 81 synchronized (localObject) { 82 dummyInt1++; 83 dummyInt2++; 84 } 85 } 86 } 87 } 88 89 /** Perform two synchronized after each other on the same local object. */ 90 @Benchmark 91 public void testSerialLockUnlock() { 92 Object localObject = lockObject1; 93 for (int i = 0; i < innerCount; i++) { 94 synchronized (localObject) { 95 dummyInt1++; 96 } 97 synchronized (localObject) { 98 dummyInt2++; 99 } 100 } 101 } 102 103 /** 104 * Performs recursive synchronizations on the same local object. 105 * <p/> 106 * Result is 3628800 107 */ 108 @Benchmark 109 public void testRecursiveSynchronization() { 110 factorial = fact(10); 111 } 112 113 private synchronized int fact(int n) { 114 if (n == 0) { 115 return 1; 116 } else { 117 return fact(n - 1) * n; 118 } 119 } 120 121 /** 122 * With two threads lockObject1 will be contended so should be 123 * inflated. 124 */ 125 @Threads(2) 126 @Benchmark 127 public void testContendedLock() { 128 synchronized (lockObject1) { 129 dummyInt1++; 130 } 131 } 132 }