1 /*
2 * Copyright (c) 2001, 2010, 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_VM_GC_IMPLEMENTATION_G1_BUFFERINGOOPCLOSURE_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_BUFFERINGOOPCLOSURE_HPP
27
28 #include "memory/genOopClosures.hpp"
29 #include "memory/generation.hpp"
30 #include "runtime/os.hpp"
31 #include "utilities/taskqueue.hpp"
32
33 // A BufferingOops closure tries to separate out the cost of finding roots
34 // from the cost of applying closures to them. It maintains an array of
35 // ref-containing locations. Until the array is full, applying the closure
36 // to an oop* merely records that location in the array. Since this
37 // closure app cost is small, an elapsed timer can approximately attribute
38 // all of this cost to the cost of finding the roots. When the array fills
39 // up, the wrapped closure is applied to all elements, keeping track of
40 // this elapsed time of this process, and leaving the array empty.
41 // The caller must be sure to call "done" to process any unprocessed
42 // buffered entriess.
43
44 class Generation;
45 class HeapRegion;
46
47 class BufferingOopClosure: public OopClosure {
48 protected:
49 enum PrivateConstants {
50 BufferLength = 1024
51 };
52
53 StarTask _buffer[BufferLength];
54 StarTask* _buffer_top;
55 StarTask* _buffer_curr;
56
57 OopClosure* _oc;
58 double _closure_app_seconds;
59
60 void process_buffer () {
61 double start = os::elapsedTime();
62 for (StarTask* curr = _buffer; curr < _buffer_curr; ++curr) {
63 if (curr->is_narrow()) {
64 assert(UseCompressedOops, "Error");
65 _oc->do_oop((narrowOop*)(*curr));
66 } else {
67 _oc->do_oop((oop*)(*curr));
68 }
69 }
70 _buffer_curr = _buffer;
71 _closure_app_seconds += (os::elapsedTime() - start);
72 }
73
74 template <class T> inline void do_oop_work(T* p) {
75 if (_buffer_curr == _buffer_top) {
76 process_buffer();
77 }
78 StarTask new_ref(p);
79 *_buffer_curr = new_ref;
80 ++_buffer_curr;
81 }
82
83 public:
84 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
85 virtual void do_oop(oop* p) { do_oop_work(p); }
86
87 void done () {
88 if (_buffer_curr > _buffer) {
89 process_buffer();
90 }
91 }
92 double closure_app_seconds () {
93 return _closure_app_seconds;
94 }
95 BufferingOopClosure (OopClosure *oc) :
96 _oc(oc),
97 _buffer_curr(_buffer), _buffer_top(_buffer + BufferLength),
98 _closure_app_seconds(0.0) { }
99 };
100
101 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_BUFFERINGOOPCLOSURE_HPP
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1 /*
2 * Copyright (c) 2001, 2014, 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_VM_GC_IMPLEMENTATION_G1_BUFFERINGOOPCLOSURE_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_BUFFERINGOOPCLOSURE_HPP
27
28 #include "memory/iterator.hpp"
29 #include "runtime/os.hpp"
30 #include "utilities/debug.hpp"
31
32 // A BufferingOops closure tries to separate out the cost of finding roots
33 // from the cost of applying closures to them. It maintains an array of
34 // ref-containing locations. Until the array is full, applying the closure
35 // to an oop* merely records that location in the array. Since this
36 // closure app cost is small, an elapsed timer can approximately attribute
37 // all of this cost to the cost of finding the roots. When the array fills
38 // up, the wrapped closure is applied to all elements, keeping track of
39 // this elapsed time of this process, and leaving the array empty.
40 // The caller must be sure to call "done" to process any unprocessed
41 // buffered entries.
42
43 class BufferingOopClosure: public OopClosure {
44 friend class TestBufferingOopClosure;
45 protected:
46 static const size_t BufferLength = 1024;
47
48 // The full-sized oops are filled in from the bottom,
49 // while the narrowOops are filled in from the top.
50 void* _buffer[BufferLength];
51 void** _oop_top;
52 void** _narrowOop_bottom;
53
54 OopClosure* _oc;
55 double _closure_app_seconds;
56
57
58 bool is_buffer_empty() {
59 return _oop_top == _buffer && _narrowOop_bottom == (_buffer + BufferLength - 1);
60 }
61
62 bool is_buffer_full() {
63 return (uintptr_t)_narrowOop_bottom < (uintptr_t)_oop_top;
64 }
65
66 // Process addresses containing full-sized oops.
67 void process_oops() {
68 for (void** curr = _buffer; curr < _oop_top; ++curr) {
69 _oc->do_oop((oop*)(*curr));
70 }
71 _oop_top = _buffer;
72 }
73
74 // Process addresses containing narrow oops.
75 void process_narrowOops() {
76 for (void** curr = _buffer + BufferLength - 1; curr > _narrowOop_bottom; --curr) {
77 _oc->do_oop((narrowOop*)(*curr));
78 }
79 _narrowOop_bottom = _buffer + BufferLength - 1;
80 }
81
82 // Apply the closure to all oops and clear the buffer.
83 // Accumulate the time it took.
84 void process_buffer() {
85 double start = os::elapsedTime();
86
87 process_oops();
88 process_narrowOops();
89
90 _closure_app_seconds += (os::elapsedTime() - start);
91 }
92
93 void process_buffer_if_full() {
94 if (is_buffer_full()) {
95 process_buffer();
96 }
97 }
98
99 void add_narrowOop(narrowOop* p) {
100 assert(!is_buffer_full(), "Buffer should not be full");
101 *_narrowOop_bottom = (void*)p;
102 _narrowOop_bottom--;
103 }
104
105 void add_oop(oop* p) {
106 assert(!is_buffer_full(), "Buffer should not be full");
107 *_oop_top = (void*)p;
108 _oop_top++;
109 }
110
111 public:
112 virtual void do_oop(narrowOop* p) {
113 process_buffer_if_full();
114 add_narrowOop(p);
115 }
116
117 virtual void do_oop(oop* p) {
118 process_buffer_if_full();
119 add_oop(p);
120 }
121
122 void done() {
123 if (!is_buffer_empty()) {
124 process_buffer();
125 }
126 }
127
128 double closure_app_seconds() {
129 return _closure_app_seconds;
130 }
131
132 BufferingOopClosure(OopClosure *oc) :
133 _oc(oc),
134 _oop_top(_buffer),
135 _narrowOop_bottom(_buffer + BufferLength - 1),
136 _closure_app_seconds(0.0) { }
137 };
138
139 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_BUFFERINGOOPCLOSURE_HPP
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