90 lines
2.9 KiB
Java
90 lines
2.9 KiB
Java
/*
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* Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package org.openjdk.bench.java.lang;
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import org.openjdk.jmh.annotations.BenchmarkMode;
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import org.openjdk.jmh.annotations.Fork;
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import org.openjdk.jmh.annotations.Benchmark;
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import org.openjdk.jmh.annotations.Measurement;
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import org.openjdk.jmh.annotations.Mode;
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import org.openjdk.jmh.annotations.OutputTimeUnit;
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import org.openjdk.jmh.annotations.Warmup;
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import java.util.concurrent.TimeUnit;
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/**
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* This benchmark assesses different hashCode strategies in HotSpot
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*/
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@BenchmarkMode(Mode.AverageTime)
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@OutputTimeUnit(TimeUnit.NANOSECONDS)
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@Warmup(iterations = 10, time = 1)
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@Measurement(iterations = 5, time = 1)
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@Fork(2)
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public class ObjectHashCode {
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@Benchmark
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public int mode_default() {
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return System.identityHashCode(new Object());
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}
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// Experimental hashCode generation schemes. See synchronizer.cpp get_next_hash
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/*
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@Benchmark
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@Fork(jvmArgs = {"-XX:+UnlockExperimentalVMOptions", "-XX:hashCode=0"})
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public int mode_0() {
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return System.identityHashCode(new Object());
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}
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@Benchmark
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@Fork(jvmArgs = {"-XX:+UnlockExperimentalVMOptions", "-XX:hashCode=1"})
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public int mode_1() {
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return System.identityHashCode(new Object());
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}
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@Benchmark
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@Fork(jvmArgs = {"-XX:+UnlockExperimentalVMOptions", "-XX:hashCode=2"})
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public int mode_2() {
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return System.identityHashCode(new Object());
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}
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@Benchmark
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@Fork(jvmArgs = {"-XX:+UnlockExperimentalVMOptions", "-XX:hashCode=3"})
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public int mode_3() {
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return System.identityHashCode(new Object());
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}
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@Benchmark
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@Fork(jvmArgs = {"-XX:+UnlockExperimentalVMOptions", "-XX:hashCode=4"})
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public int mode_4() {
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return System.identityHashCode(new Object());
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}
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@Benchmark
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@Fork(jvmArgs = {"-XX:+UnlockExperimentalVMOptions", "-XX:hashCode=5"})
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public int mode_5() {
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return System.identityHashCode(new Object());
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}
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*/
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}
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