1/*
2 * Copyright (c) 2003, 2019, 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 */
24
25#ifndef SHARE_RUNTIME_PREFETCH_HPP
26#define SHARE_RUNTIME_PREFETCH_HPP
27
28#include "memory/allocation.hpp"
29
30// If calls to prefetch methods are in a loop, the loop should be cloned
31// such that if Prefetch{Scan,Copy}Interval and/or PrefetchFieldInterval
32// say not to do prefetching, these methods aren't called. At the very
33// least, they take up a memory issue slot. They should be implemented
34// as inline assembly code: doing an actual call isn't worth the cost.
35
36class Prefetch : AllStatic {
37 public:
38 enum style {
39 do_none, // Do no prefetching
40 do_read, // Do read prefetching
41 do_write // Do write prefetching
42 };
43
44 // Prefetch anticipating read; must not fault, semantically a no-op
45 static void read(void* loc, intx interval);
46
47 // Prefetch anticipating write; must not fault, semantically a no-op
48 static void write(void* loc, intx interval);
49};
50
51#endif // SHARE_RUNTIME_PREFETCH_HPP
52