Fri, 12 Jun 2009 16:20:16 -0400
6850846: G1: extend G1 marking verification
Summary: extend G1 marking verification to use either the "prev" or "next" marking information, as appropriate.
Reviewed-by: johnc, ysr
1 /*
2 * Copyright 2001-2007 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/_concurrentG1RefineThread.cpp.incl"
28 // ======= Concurrent Mark Thread ========
30 // The CM thread is created when the G1 garbage collector is used
32 ConcurrentG1RefineThread::
33 ConcurrentG1RefineThread(ConcurrentG1Refine* cg1r, ConcurrentG1RefineThread *next,
34 int worker_id_offset, int worker_id) :
35 ConcurrentGCThread(),
36 _worker_id_offset(worker_id_offset),
37 _worker_id(worker_id),
38 _active(false),
39 _next(next),
40 _cg1r(cg1r),
41 _vtime_accum(0.0),
42 _co_tracker(G1CRGroup),
43 _interval_ms(5.0)
44 {
45 create_and_start();
46 }
48 void ConcurrentG1RefineThread::sample_young_list_rs_lengths() {
49 G1CollectedHeap* g1h = G1CollectedHeap::heap();
50 G1CollectorPolicy* g1p = g1h->g1_policy();
51 if (g1p->adaptive_young_list_length()) {
52 int regions_visited = 0;
54 g1h->young_list_rs_length_sampling_init();
55 while (g1h->young_list_rs_length_sampling_more()) {
56 g1h->young_list_rs_length_sampling_next();
57 ++regions_visited;
59 // we try to yield every time we visit 10 regions
60 if (regions_visited == 10) {
61 if (_sts.should_yield()) {
62 _sts.yield("G1 refine");
63 // we just abandon the iteration
64 break;
65 }
66 regions_visited = 0;
67 }
68 }
70 g1p->check_prediction_validity();
71 }
72 }
74 void ConcurrentG1RefineThread::run() {
75 initialize_in_thread();
76 _vtime_start = os::elapsedVTime();
77 wait_for_universe_init();
79 _co_tracker.enable();
80 _co_tracker.start();
82 while (!_should_terminate) {
83 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
84 // Wait for completed log buffers to exist.
85 {
86 MutexLockerEx x(DirtyCardQ_CBL_mon, Mutex::_no_safepoint_check_flag);
87 while (((_worker_id == 0 && !dcqs.process_completed_buffers()) ||
88 (_worker_id > 0 && !is_active())) &&
89 !_should_terminate) {
90 DirtyCardQ_CBL_mon->wait(Mutex::_no_safepoint_check_flag);
91 }
92 }
94 if (_should_terminate) {
95 return;
96 }
98 // Now we take them off (this doesn't hold locks while it applies
99 // closures.) (If we did a full collection, then we'll do a full
100 // traversal.
101 _sts.join();
102 int n_logs = 0;
103 int lower_limit = 0;
104 double start_vtime_sec; // only used when G1SmoothConcRefine is on
105 int prev_buffer_num; // only used when G1SmoothConcRefine is on
106 // This thread activation threshold
107 int threshold = DCQBarrierProcessCompletedThreshold * _worker_id;
108 // Next thread activation threshold
109 int next_threshold = threshold + DCQBarrierProcessCompletedThreshold;
110 int deactivation_threshold = MAX2<int>(threshold - DCQBarrierProcessCompletedThreshold / 2, 0);
112 if (G1SmoothConcRefine) {
113 lower_limit = 0;
114 start_vtime_sec = os::elapsedVTime();
115 prev_buffer_num = (int) dcqs.completed_buffers_num();
116 } else {
117 lower_limit = DCQBarrierProcessCompletedThreshold / 4; // For now.
118 }
119 while (dcqs.apply_closure_to_completed_buffer(_worker_id + _worker_id_offset, lower_limit)) {
120 double end_vtime_sec;
121 double elapsed_vtime_sec;
122 int elapsed_vtime_ms;
123 int curr_buffer_num = (int) dcqs.completed_buffers_num();
125 if (G1SmoothConcRefine) {
126 end_vtime_sec = os::elapsedVTime();
127 elapsed_vtime_sec = end_vtime_sec - start_vtime_sec;
128 elapsed_vtime_ms = (int) (elapsed_vtime_sec * 1000.0);
130 if (curr_buffer_num > prev_buffer_num ||
131 curr_buffer_num > next_threshold) {
132 decreaseInterval(elapsed_vtime_ms);
133 } else if (curr_buffer_num < prev_buffer_num) {
134 increaseInterval(elapsed_vtime_ms);
135 }
136 }
137 if (_worker_id == 0) {
138 sample_young_list_rs_lengths();
139 } else if (curr_buffer_num < deactivation_threshold) {
140 // If the number of the buffer has fallen below our threshold
141 // we should deactivate. The predecessor will reactivate this
142 // thread should the number of the buffers cross the threshold again.
143 MutexLockerEx x(DirtyCardQ_CBL_mon, Mutex::_no_safepoint_check_flag);
144 deactivate();
145 if (G1TraceConcurrentRefinement) {
146 gclog_or_tty->print_cr("G1-Refine-deactivated worker %d", _worker_id);
147 }
148 break;
149 }
150 _co_tracker.update(false);
152 // Check if we need to activate the next thread.
153 if (curr_buffer_num > next_threshold && _next != NULL && !_next->is_active()) {
154 MutexLockerEx x(DirtyCardQ_CBL_mon, Mutex::_no_safepoint_check_flag);
155 _next->activate();
156 DirtyCardQ_CBL_mon->notify_all();
157 if (G1TraceConcurrentRefinement) {
158 gclog_or_tty->print_cr("G1-Refine-activated worker %d", _next->_worker_id);
159 }
160 }
162 if (G1SmoothConcRefine) {
163 prev_buffer_num = curr_buffer_num;
164 _sts.leave();
165 os::sleep(Thread::current(), (jlong) _interval_ms, false);
166 _sts.join();
167 start_vtime_sec = os::elapsedVTime();
168 }
169 n_logs++;
170 }
171 _co_tracker.update(false);
172 _sts.leave();
174 if (os::supports_vtime()) {
175 _vtime_accum = (os::elapsedVTime() - _vtime_start);
176 } else {
177 _vtime_accum = 0.0;
178 }
179 }
180 _sts.join();
181 _co_tracker.update(true);
182 _sts.leave();
183 assert(_should_terminate, "just checking");
185 terminate();
186 }
189 void ConcurrentG1RefineThread::yield() {
190 if (G1TraceConcurrentRefinement) gclog_or_tty->print_cr("G1-Refine-yield");
191 _sts.yield("G1 refine");
192 if (G1TraceConcurrentRefinement) gclog_or_tty->print_cr("G1-Refine-yield-end");
193 }
195 void ConcurrentG1RefineThread::stop() {
196 // it is ok to take late safepoints here, if needed
197 {
198 MutexLockerEx mu(Terminator_lock);
199 _should_terminate = true;
200 }
202 {
203 MutexLockerEx x(DirtyCardQ_CBL_mon, Mutex::_no_safepoint_check_flag);
204 DirtyCardQ_CBL_mon->notify_all();
205 }
207 {
208 MutexLockerEx mu(Terminator_lock);
209 while (!_has_terminated) {
210 Terminator_lock->wait();
211 }
212 }
213 if (G1TraceConcurrentRefinement) gclog_or_tty->print_cr("G1-Refine-stop");
214 }
216 void ConcurrentG1RefineThread::print() {
217 gclog_or_tty->print("\"Concurrent G1 Refinement Thread\" ");
218 Thread::print();
219 gclog_or_tty->cr();
220 }