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