Mercurial > hg > truffle
view test/compiler/6968348/Test6968348.java @ 2134:b158bed62ef5
6994297: G1: do first-level slow-path allocations with a CAS
Summary: First attempt to allocate out the current alloc region using a CAS instead of taking the Heap_lock (first level of G1's slow allocation path). Only if that fails and it's necessary to replace the current alloc region take the Heap_lock (that's the second level of G1's slow allocation path).
Reviewed-by: johnc, brutisso, ysr
author | tonyp |
---|---|
date | Wed, 12 Jan 2011 16:34:25 -0500 |
parents | 52e82a6bedaf |
children |
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/* * Copyright (c) 2010, Oracle and/or its affiliates. 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. * * 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. * */ /** * @test * @bug 6968348 * @summary Byteswapped memory access can point to wrong location after JIT * * @run main Test6968348 */ import sun.misc.Unsafe; import java.lang.reflect.*; public class Test6968348 { static Unsafe unsafe; static final long[] buffer = new long[4096]; static int array_long_base_offset; public static void main(String[] args) throws Exception { Class c = Test6968348.class.getClassLoader().loadClass("sun.misc.Unsafe"); Field f = c.getDeclaredField("theUnsafe"); f.setAccessible(true); unsafe = (Unsafe)f.get(c); array_long_base_offset = unsafe.arrayBaseOffset(long[].class); for (int n = 0; n < 100000; n++) { test(); } } public static void test() { for (long i = array_long_base_offset; i < 4096; i += 8) { unsafe.putLong(buffer, i, Long.reverseBytes(i)); } } }