Mercurial > hg > gc-bench
view src/main/java/org/openjdk/gcbench/retain/WeakHashMaps.java @ 88:583fef4276f5
Update license and copyright headers.
author | shade |
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date | Wed, 22 Nov 2017 15:58:02 +0100 |
parents | f8cde6220e90 |
children | 14c1bb4faa6e |
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/* * Copyright (c) 2017, Red Hat Inc. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package org.openjdk.gcbench.retain; import org.openjdk.jmh.annotations.*; import java.util.HashMap; import java.util.LinkedList; import java.util.Optional; import java.util.WeakHashMap; import java.util.concurrent.TimeUnit; @Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS) @Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS) @Fork(1) @BenchmarkMode(Mode.AverageTime) @OutputTimeUnit(TimeUnit.NANOSECONDS) @Threads(Threads.MAX) @State(Scope.Benchmark) public class WeakHashMaps { Object retain; @Param({"100000"}) private int size; @Setup public void setup() { WeakHashMap<Object, Object> map = new WeakHashMap<>(); for (int c = 0; c < size; c++) { Object v = new Object(); // deadly-embrace to keep weak key strongly reachable; // also make sure the value is one dereference forward, in order // to let VM discover the reference first, not the referent. map.put(v, Optional.of(v)); } retain = map; } @Benchmark public Object test() { // allocation pressure to trigger GCs return new Object(); } }