Wed, 16 Dec 2009 15:12:51 -0800
6862387: tune concurrent refinement further
Summary: Reworked the concurrent refinement: threads activation, feedback-based threshold adjustment, other miscellaneous fixes.
Reviewed-by: apetrusenko, tonyp
1 /*
2 * Copyright 2001-2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 # include "incls/_precompiled.incl"
26 # include "incls/_ptrQueue.cpp.incl"
28 PtrQueue::PtrQueue(PtrQueueSet* qset_, bool perm) :
29 _qset(qset_), _buf(NULL), _index(0), _active(false),
30 _perm(perm), _lock(NULL)
31 {}
33 void PtrQueue::flush() {
34 if (!_perm && _buf != NULL) {
35 if (_index == _sz) {
36 // No work to do.
37 qset()->deallocate_buffer(_buf);
38 } else {
39 // We must NULL out the unused entries, then enqueue.
40 for (size_t i = 0; i < _index; i += oopSize) {
41 _buf[byte_index_to_index((int)i)] = NULL;
42 }
43 qset()->enqueue_complete_buffer(_buf);
44 }
45 _buf = NULL;
46 _index = 0;
47 }
48 }
51 static int byte_index_to_index(int ind) {
52 assert((ind % oopSize) == 0, "Invariant.");
53 return ind / oopSize;
54 }
56 static int index_to_byte_index(int byte_ind) {
57 return byte_ind * oopSize;
58 }
60 void PtrQueue::enqueue_known_active(void* ptr) {
61 assert(0 <= _index && _index <= _sz, "Invariant.");
62 assert(_index == 0 || _buf != NULL, "invariant");
64 while (_index == 0) {
65 handle_zero_index();
66 }
68 assert(_index > 0, "postcondition");
69 _index -= oopSize;
70 _buf[byte_index_to_index((int)_index)] = ptr;
71 assert(0 <= _index && _index <= _sz, "Invariant.");
72 }
74 void PtrQueue::locking_enqueue_completed_buffer(void** buf) {
75 assert(_lock->owned_by_self(), "Required.");
76 _lock->unlock();
77 qset()->enqueue_complete_buffer(buf);
78 // We must relock only because the caller will unlock, for the normal
79 // case.
80 _lock->lock_without_safepoint_check();
81 }
84 PtrQueueSet::PtrQueueSet(bool notify_when_complete) :
85 _max_completed_queue(0),
86 _cbl_mon(NULL), _fl_lock(NULL),
87 _notify_when_complete(notify_when_complete),
88 _sz(0),
89 _completed_buffers_head(NULL),
90 _completed_buffers_tail(NULL),
91 _n_completed_buffers(0),
92 _process_completed_threshold(0), _process_completed(false),
93 _buf_free_list(NULL), _buf_free_list_sz(0)
94 {
95 _fl_owner = this;
96 }
98 void** PtrQueueSet::allocate_buffer() {
99 assert(_sz > 0, "Didn't set a buffer size.");
100 MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);
101 if (_fl_owner->_buf_free_list != NULL) {
102 void** res = BufferNode::make_buffer_from_node(_fl_owner->_buf_free_list);
103 _fl_owner->_buf_free_list = _fl_owner->_buf_free_list->next();
104 _fl_owner->_buf_free_list_sz--;
105 return res;
106 } else {
107 // Allocate space for the BufferNode in front of the buffer.
108 char *b = NEW_C_HEAP_ARRAY(char, _sz + BufferNode::aligned_size());
109 return BufferNode::make_buffer_from_block(b);
110 }
111 }
113 void PtrQueueSet::deallocate_buffer(void** buf) {
114 assert(_sz > 0, "Didn't set a buffer size.");
115 MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);
116 BufferNode *node = BufferNode::make_node_from_buffer(buf);
117 node->set_next(_fl_owner->_buf_free_list);
118 _fl_owner->_buf_free_list = node;
119 _fl_owner->_buf_free_list_sz++;
120 }
122 void PtrQueueSet::reduce_free_list() {
123 assert(_fl_owner == this, "Free list reduction is allowed only for the owner");
124 // For now we'll adopt the strategy of deleting half.
125 MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag);
126 size_t n = _buf_free_list_sz / 2;
127 while (n > 0) {
128 assert(_buf_free_list != NULL, "_buf_free_list_sz must be wrong.");
129 void* b = BufferNode::make_block_from_node(_buf_free_list);
130 _buf_free_list = _buf_free_list->next();
131 FREE_C_HEAP_ARRAY(char, b);
132 _buf_free_list_sz --;
133 n--;
134 }
135 }
137 void PtrQueue::handle_zero_index() {
138 assert(0 == _index, "Precondition.");
139 // This thread records the full buffer and allocates a new one (while
140 // holding the lock if there is one).
141 if (_buf != NULL) {
142 if (_lock) {
143 locking_enqueue_completed_buffer(_buf);
144 } else {
145 if (qset()->process_or_enqueue_complete_buffer(_buf)) {
146 // Recycle the buffer. No allocation.
147 _sz = qset()->buffer_size();
148 _index = _sz;
149 return;
150 }
151 }
152 }
153 // Reallocate the buffer
154 _buf = qset()->allocate_buffer();
155 _sz = qset()->buffer_size();
156 _index = _sz;
157 assert(0 <= _index && _index <= _sz, "Invariant.");
158 }
160 bool PtrQueueSet::process_or_enqueue_complete_buffer(void** buf) {
161 if (Thread::current()->is_Java_thread()) {
162 // We don't lock. It is fine to be epsilon-precise here.
163 if (_max_completed_queue == 0 || _max_completed_queue > 0 &&
164 _n_completed_buffers >= _max_completed_queue + _completed_queue_padding) {
165 bool b = mut_process_buffer(buf);
166 if (b) {
167 // True here means that the buffer hasn't been deallocated and the caller may reuse it.
168 return true;
169 }
170 }
171 }
172 // The buffer will be enqueued. The caller will have to get a new one.
173 enqueue_complete_buffer(buf);
174 return false;
175 }
177 void PtrQueueSet::enqueue_complete_buffer(void** buf, size_t index) {
178 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
179 BufferNode* cbn = BufferNode::new_from_buffer(buf);
180 cbn->set_index(index);
181 if (_completed_buffers_tail == NULL) {
182 assert(_completed_buffers_head == NULL, "Well-formedness");
183 _completed_buffers_head = cbn;
184 _completed_buffers_tail = cbn;
185 } else {
186 _completed_buffers_tail->set_next(cbn);
187 _completed_buffers_tail = cbn;
188 }
189 _n_completed_buffers++;
191 if (!_process_completed && _process_completed_threshold >= 0 &&
192 _n_completed_buffers >= _process_completed_threshold) {
193 _process_completed = true;
194 if (_notify_when_complete)
195 _cbl_mon->notify();
196 }
197 debug_only(assert_completed_buffer_list_len_correct_locked());
198 }
200 int PtrQueueSet::completed_buffers_list_length() {
201 int n = 0;
202 BufferNode* cbn = _completed_buffers_head;
203 while (cbn != NULL) {
204 n++;
205 cbn = cbn->next();
206 }
207 return n;
208 }
210 void PtrQueueSet::assert_completed_buffer_list_len_correct() {
211 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
212 assert_completed_buffer_list_len_correct_locked();
213 }
215 void PtrQueueSet::assert_completed_buffer_list_len_correct_locked() {
216 guarantee(completed_buffers_list_length() == _n_completed_buffers,
217 "Completed buffer length is wrong.");
218 }
220 void PtrQueueSet::set_buffer_size(size_t sz) {
221 assert(_sz == 0 && sz > 0, "Should be called only once.");
222 _sz = sz * oopSize;
223 }
225 // Merge lists of buffers. Notify the processing threads.
226 // The source queue is emptied as a result. The queues
227 // must share the monitor.
228 void PtrQueueSet::merge_bufferlists(PtrQueueSet *src) {
229 assert(_cbl_mon == src->_cbl_mon, "Should share the same lock");
230 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
231 if (_completed_buffers_tail == NULL) {
232 assert(_completed_buffers_head == NULL, "Well-formedness");
233 _completed_buffers_head = src->_completed_buffers_head;
234 _completed_buffers_tail = src->_completed_buffers_tail;
235 } else {
236 assert(_completed_buffers_head != NULL, "Well formedness");
237 if (src->_completed_buffers_head != NULL) {
238 _completed_buffers_tail->set_next(src->_completed_buffers_head);
239 _completed_buffers_tail = src->_completed_buffers_tail;
240 }
241 }
242 _n_completed_buffers += src->_n_completed_buffers;
244 src->_n_completed_buffers = 0;
245 src->_completed_buffers_head = NULL;
246 src->_completed_buffers_tail = NULL;
248 assert(_completed_buffers_head == NULL && _completed_buffers_tail == NULL ||
249 _completed_buffers_head != NULL && _completed_buffers_tail != NULL,
250 "Sanity");
251 }
253 void PtrQueueSet::notify_if_necessary() {
254 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
255 if (_n_completed_buffers >= _process_completed_threshold || _max_completed_queue == 0) {
256 _process_completed = true;
257 if (_notify_when_complete)
258 _cbl_mon->notify();
259 }
260 }