1 /*
 2  * Copyright (c) 2018, 2023, 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 #include "precompiled.hpp"
25 #include "runtime/objectMonitor.hpp"
26 #include "runtime/vm_version.hpp"
27 #include "unittest.hpp"
28 
29 TEST_VM(ObjectMonitor, sanity) {
30  uint cache_line_size = VM_Version::L1_data_cache_line_size();
31 
32  if (cache_line_size != 0) {
33    // We were able to determine the L1 data cache line size so
34    // do some cache line specific sanity checks
35    EXPECT_EQ((size_t) 0, sizeof (PaddedEnd<ObjectMonitor>) % cache_line_size)
36         << "PaddedEnd<ObjectMonitor> size is not a "
37         << "multiple of a cache line which permits false sharing. "
38         << "sizeof(PaddedEnd<ObjectMonitor>) = "
39         << sizeof (PaddedEnd<ObjectMonitor>)
40         << "; cache_line_size = " << cache_line_size;
41 
42    EXPECT_GE((size_t) in_bytes(ObjectMonitor::owner_offset()), cache_line_size)
43         << "the _header and _owner fields are closer "
44         << "than a cache line which permits false sharing.";
45   }
46 }