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. 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.java.util.concurrent; 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.Scope; 30 import org.openjdk.jmh.annotations.Setup; 31 import org.openjdk.jmh.annotations.State; 32 import org.openjdk.jmh.annotations.Threads; 33 34 import java.util.Map; 35 import java.util.concurrent.ConcurrentHashMap; 36 import java.util.concurrent.TimeUnit; 37 import java.util.concurrent.atomic.AtomicLong; 38 39 @BenchmarkMode(Mode.AverageTime) 40 @OutputTimeUnit(TimeUnit.NANOSECONDS) 41 @State(Scope.Benchmark) 42 public class Maps { 43 private SimpleRandom rng; 44 private Map<Integer, Integer> map; 45 private Integer[] key; 46 47 private int removesPerMaxRandom; 48 private int insertsPerMaxRandom; 49 private int total; 50 private int position; 51 52 @Setup 53 public void initTest() { 54 int nkeys = 10000; 55 int pRemove = 10; 56 int pInsert = 90; 57 removesPerMaxRandom = (int) ((pRemove / 100.0 * 0x7FFFFFFFL)); 58 insertsPerMaxRandom = (int) ((pInsert / 100.0 * 0x7FFFFFFFL)); 59 60 rng = new SimpleRandom(); 61 map = new ConcurrentHashMap<>(); 62 total = 0; 63 key = new Integer[nkeys]; 64 for (int i = 0; i < key.length; ++i) { 65 key[i] = new Integer(rng.next()); 66 } 67 position = key.length / 2; 68 } 69 70 @Benchmark 71 @Threads(4) 72 public void testConcurrentHashMap() { 73 int pos = position; 74 // random-walk around key positions, bunching accesses 75 int r = rng.next(); 76 pos += (r & 7) - 3; 77 while (pos >= key.length) { 78 pos -= key.length; 79 } 80 while (pos < 0) { 81 pos += key.length; 82 } 83 Integer k = key[pos]; 84 Integer x = map.get(k); 85 if (x != null) { 86 if (x.intValue() != k.intValue()) { 87 throw new Error("bad mapping: " + x + " to " + k); 88 } 89 90 if (r < removesPerMaxRandom) { 91 if (map.remove(k) != null) { 92 pos = total % key.length; // move from position 93 } 94 } 95 } else if (r < insertsPerMaxRandom) { 96 ++pos; 97 map.put(k, k); 98 } 99 total += r; 100 position = pos; 101 } 102 103 private static class SimpleRandom { 104 private final static long multiplier = 0x5DEECE66DL; 105 private final static long addend = 0xBL; 106 private final static long mask = (1L << 48) - 1; 107 private final static AtomicLong seq = new AtomicLong(1); 108 private long seed = System.nanoTime() + seq.getAndIncrement(); 109 110 public int next() { 111 long nextSeed = (seed * multiplier + addend) & mask; 112 seed = nextSeed; 113 return ((int) (nextSeed >>> 17)) & 0x7FFFFFFF; 114 } 115 } 116 }