1 /*
2 * Copyright (c) 2001, 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 #include "precompiled.hpp"
26 #include "gc/g1/g1BarrierSet.hpp"
27 #include "gc/g1/g1ConcurrentRefine.hpp"
28 #include "gc/g1/g1ConcurrentRefineThread.hpp"
29 #include "gc/g1/g1DirtyCardQueue.hpp"
30 #include "logging/log.hpp"
31 #include "memory/allocation.inline.hpp"
32 #include "runtime/java.hpp"
33 #include "runtime/thread.hpp"
34 #include "utilities/debug.hpp"
35 #include "utilities/globalDefinitions.hpp"
36 #include "utilities/pair.hpp"
37 #include <math.h>
38
39 G1ConcurrentRefineThread* G1ConcurrentRefineThreadControl::create_refinement_thread(uint worker_id, bool initializing) {
40 G1ConcurrentRefineThread* result = NULL;
41 if (initializing || !InjectGCWorkerCreationFailure) {
42 result = new G1ConcurrentRefineThread(_cr, worker_id);
43 }
44 if (result == NULL || result->osthread() == NULL) {
45 log_warning(gc)("Failed to create refinement thread %u, no more %s",
46 worker_id,
47 result == NULL ? "memory" : "OS threads");
48 }
49 return result;
50 }
51
52 G1ConcurrentRefineThreadControl::G1ConcurrentRefineThreadControl() :
53 _cr(NULL),
54 _threads(NULL),
55 _num_max_threads(0)
56 {
57 }
58
59 G1ConcurrentRefineThreadControl::~G1ConcurrentRefineThreadControl() {
60 for (uint i = 0; i < _num_max_threads; i++) {
61 G1ConcurrentRefineThread* t = _threads[i];
62 if (t != NULL) {
63 delete t;
64 }
65 }
66 FREE_C_HEAP_ARRAY(G1ConcurrentRefineThread*, _threads);
67 }
68
69 jint G1ConcurrentRefineThreadControl::initialize(G1ConcurrentRefine* cr, uint num_max_threads) {
70 assert(cr != NULL, "G1ConcurrentRefine must not be NULL");
71 _cr = cr;
72 _num_max_threads = num_max_threads;
73
74 _threads = NEW_C_HEAP_ARRAY_RETURN_NULL(G1ConcurrentRefineThread*, num_max_threads, mtGC);
75 if (_threads == NULL) {
76 vm_shutdown_during_initialization("Could not allocate thread holder array.");
77 return JNI_ENOMEM;
78 }
79
80 for (uint i = 0; i < num_max_threads; i++) {
81 if (UseDynamicNumberOfGCThreads && i != 0 /* Always start first thread. */) {
82 _threads[i] = NULL;
83 } else {
84 _threads[i] = create_refinement_thread(i, true);
85 if (_threads[i] == NULL) {
86 vm_shutdown_during_initialization("Could not allocate refinement threads.");
87 return JNI_ENOMEM;
88 }
89 }
90 }
91 return JNI_OK;
92 }
93
94 void G1ConcurrentRefineThreadControl::maybe_activate_next(uint cur_worker_id) {
95 assert(cur_worker_id < _num_max_threads,
96 "Activating another thread from %u not allowed since there can be at most %u",
97 cur_worker_id, _num_max_threads);
98 if (cur_worker_id == (_num_max_threads - 1)) {
99 // Already the last thread, there is no more thread to activate.
100 return;
101 }
102
103 uint worker_id = cur_worker_id + 1;
104 G1ConcurrentRefineThread* thread_to_activate = _threads[worker_id];
105 if (thread_to_activate == NULL) {
106 // Still need to create the thread...
107 _threads[worker_id] = create_refinement_thread(worker_id, false);
108 thread_to_activate = _threads[worker_id];
109 }
110 if (thread_to_activate != NULL && !thread_to_activate->is_active()) {
111 thread_to_activate->activate();
112 }
113 }
114
115 void G1ConcurrentRefineThreadControl::print_on(outputStream* st) const {
116 for (uint i = 0; i < _num_max_threads; ++i) {
117 if (_threads[i] != NULL) {
118 _threads[i]->print_on(st);
119 st->cr();
120 }
121 }
122 }
123
124 void G1ConcurrentRefineThreadControl::worker_threads_do(ThreadClosure* tc) {
125 for (uint i = 0; i < _num_max_threads; i++) {
126 if (_threads[i] != NULL) {
127 tc->do_thread(_threads[i]);
128 }
129 }
130 }
131
132 void G1ConcurrentRefineThreadControl::stop() {
133 for (uint i = 0; i < _num_max_threads; i++) {
134 if (_threads[i] != NULL) {
135 _threads[i]->stop();
136 }
137 }
138 }
139
140 // Arbitrary but large limits, to simplify some of the zone calculations.
141 // The general idea is to allow expressions like
142 // MIN2(x OP y, max_XXX_zone)
143 // without needing to check for overflow in "x OP y", because the
144 // ranges for x and y have been restricted.
145 STATIC_ASSERT(sizeof(LP64_ONLY(jint) NOT_LP64(jshort)) <= (sizeof(size_t)/2));
146 const size_t max_yellow_zone = LP64_ONLY(max_jint) NOT_LP64(max_jshort);
147 const size_t max_green_zone = max_yellow_zone / 2;
148 const size_t max_red_zone = INT_MAX; // For dcqs.set_max_completed_buffers.
149 STATIC_ASSERT(max_yellow_zone <= max_red_zone);
150
151 // Range check assertions for green zone values.
152 #define assert_zone_constraints_g(green) \
153 do { \
154 size_t azc_g_green = (green); \
155 assert(azc_g_green <= max_green_zone, \
156 "green exceeds max: " SIZE_FORMAT, azc_g_green); \
157 } while (0)
158
159 // Range check assertions for green and yellow zone values.
160 #define assert_zone_constraints_gy(green, yellow) \
161 do { \
162 size_t azc_gy_green = (green); \
163 size_t azc_gy_yellow = (yellow); \
164 assert_zone_constraints_g(azc_gy_green); \
165 assert(azc_gy_yellow <= max_yellow_zone, \
166 "yellow exceeds max: " SIZE_FORMAT, azc_gy_yellow); \
167 assert(azc_gy_green <= azc_gy_yellow, \
168 "green (" SIZE_FORMAT ") exceeds yellow (" SIZE_FORMAT ")", \
169 azc_gy_green, azc_gy_yellow); \
170 } while (0)
171
172 // Range check assertions for green, yellow, and red zone values.
173 #define assert_zone_constraints_gyr(green, yellow, red) \
174 do { \
175 size_t azc_gyr_green = (green); \
176 size_t azc_gyr_yellow = (yellow); \
177 size_t azc_gyr_red = (red); \
178 assert_zone_constraints_gy(azc_gyr_green, azc_gyr_yellow); \
179 assert(azc_gyr_red <= max_red_zone, \
180 "red exceeds max: " SIZE_FORMAT, azc_gyr_red); \
181 assert(azc_gyr_yellow <= azc_gyr_red, \
182 "yellow (" SIZE_FORMAT ") exceeds red (" SIZE_FORMAT ")", \
183 azc_gyr_yellow, azc_gyr_red); \
184 } while (0)
185
186 // Logging tag sequence for refinement control updates.
187 #define CTRL_TAGS gc, ergo, refine
188
189 // For logging zone values, ensuring consistency of level and tags.
190 #define LOG_ZONES(...) log_debug( CTRL_TAGS )(__VA_ARGS__)
191
192 // Package for pair of refinement thread activation and deactivation
193 // thresholds. The activation and deactivation levels are resp. the first
194 // and second values of the pair.
195 typedef Pair<size_t, size_t> Thresholds;
196 inline size_t activation_level(const Thresholds& t) { return t.first; }
197 inline size_t deactivation_level(const Thresholds& t) { return t.second; }
198
199 static Thresholds calc_thresholds(size_t green_zone,
200 size_t yellow_zone,
201 uint worker_i) {
202 double yellow_size = yellow_zone - green_zone;
203 double step = yellow_size / G1ConcurrentRefine::max_num_threads();
204 if (worker_i == 0) {
205 // Potentially activate worker 0 more aggressively, to keep
206 // available buffers near green_zone value. When yellow_size is
207 // large we don't want to allow a full step to accumulate before
208 // doing any processing, as that might lead to significantly more
209 // than green_zone buffers to be processed by update_rs.
210 step = MIN2(step, ParallelGCThreads / 2.0);
211 }
212 size_t activate_offset = static_cast<size_t>(ceil(step * (worker_i + 1)));
213 size_t deactivate_offset = static_cast<size_t>(floor(step * worker_i));
214 return Thresholds(green_zone + activate_offset,
215 green_zone + deactivate_offset);
216 }
217
218 G1ConcurrentRefine::G1ConcurrentRefine(size_t green_zone,
219 size_t yellow_zone,
220 size_t red_zone,
221 size_t min_yellow_zone_size) :
222 _thread_control(),
223 _green_zone(green_zone),
224 _yellow_zone(yellow_zone),
225 _red_zone(red_zone),
226 _min_yellow_zone_size(min_yellow_zone_size)
227 {
228 assert_zone_constraints_gyr(green_zone, yellow_zone, red_zone);
229 }
230
231 jint G1ConcurrentRefine::initialize() {
232 return _thread_control.initialize(this, max_num_threads());
233 }
234
235 static size_t calc_min_yellow_zone_size() {
236 size_t step = G1ConcRefinementThresholdStep;
237 uint n_workers = G1ConcurrentRefine::max_num_threads();
238 if ((max_yellow_zone / step) < n_workers) {
239 return max_yellow_zone;
240 } else {
241 return step * n_workers;
242 }
243 }
244
245 static size_t calc_init_green_zone() {
246 size_t green = G1ConcRefinementGreenZone;
247 if (FLAG_IS_DEFAULT(G1ConcRefinementGreenZone)) {
248 green = ParallelGCThreads;
249 }
250 return MIN2(green, max_green_zone);
251 }
252
253 static size_t calc_init_yellow_zone(size_t green, size_t min_size) {
254 size_t config = G1ConcRefinementYellowZone;
255 size_t size = 0;
256 if (FLAG_IS_DEFAULT(G1ConcRefinementYellowZone)) {
257 size = green * 2;
258 } else if (green < config) {
259 size = config - green;
260 }
261 size = MAX2(size, min_size);
262 size = MIN2(size, max_yellow_zone);
263 return MIN2(green + size, max_yellow_zone);
264 }
265
266 static size_t calc_init_red_zone(size_t green, size_t yellow) {
267 size_t size = yellow - green;
268 if (!FLAG_IS_DEFAULT(G1ConcRefinementRedZone)) {
269 size_t config = G1ConcRefinementRedZone;
270 if (yellow < config) {
271 size = MAX2(size, config - yellow);
272 }
273 }
274 return MIN2(yellow + size, max_red_zone);
275 }
276
277 G1ConcurrentRefine* G1ConcurrentRefine::create(jint* ecode) {
278 size_t min_yellow_zone_size = calc_min_yellow_zone_size();
279 size_t green_zone = calc_init_green_zone();
280 size_t yellow_zone = calc_init_yellow_zone(green_zone, min_yellow_zone_size);
281 size_t red_zone = calc_init_red_zone(green_zone, yellow_zone);
282
283 LOG_ZONES("Initial Refinement Zones: "
284 "green: " SIZE_FORMAT ", "
285 "yellow: " SIZE_FORMAT ", "
286 "red: " SIZE_FORMAT ", "
287 "min yellow size: " SIZE_FORMAT,
288 green_zone, yellow_zone, red_zone, min_yellow_zone_size);
289
290 G1ConcurrentRefine* cr = new G1ConcurrentRefine(green_zone,
291 yellow_zone,
292 red_zone,
293 min_yellow_zone_size);
294
295 if (cr == NULL) {
296 *ecode = JNI_ENOMEM;
297 vm_shutdown_during_initialization("Could not create G1ConcurrentRefine");
298 return NULL;
299 }
300
301 *ecode = cr->initialize();
302 return cr;
303 }
304
305 void G1ConcurrentRefine::stop() {
306 _thread_control.stop();
307 }
308
309 G1ConcurrentRefine::~G1ConcurrentRefine() {
310 }
311
312 void G1ConcurrentRefine::threads_do(ThreadClosure *tc) {
313 _thread_control.worker_threads_do(tc);
314 }
315
316 uint G1ConcurrentRefine::max_num_threads() {
317 return G1ConcRefinementThreads;
318 }
319
320 void G1ConcurrentRefine::print_threads_on(outputStream* st) const {
321 _thread_control.print_on(st);
322 }
323
324 static size_t calc_new_green_zone(size_t green,
325 double update_rs_time,
326 size_t update_rs_processed_buffers,
327 double goal_ms) {
328 // Adjust green zone based on whether we're meeting the time goal.
329 // Limit to max_green_zone.
330 const double inc_k = 1.1, dec_k = 0.9;
331 if (update_rs_time > goal_ms) {
332 if (green > 0) {
333 green = static_cast<size_t>(green * dec_k);
334 }
335 } else if (update_rs_time < goal_ms &&
336 update_rs_processed_buffers > green) {
337 green = static_cast<size_t>(MAX2(green * inc_k, green + 1.0));
338 green = MIN2(green, max_green_zone);
339 }
340 return green;
341 }
342
343 static size_t calc_new_yellow_zone(size_t green, size_t min_yellow_size) {
344 size_t size = green * 2;
345 size = MAX2(size, min_yellow_size);
346 return MIN2(green + size, max_yellow_zone);
347 }
348
349 static size_t calc_new_red_zone(size_t green, size_t yellow) {
350 return MIN2(yellow + (yellow - green), max_red_zone);
351 }
352
353 void G1ConcurrentRefine::update_zones(double update_rs_time,
354 size_t update_rs_processed_buffers,
355 double goal_ms) {
356 log_trace( CTRL_TAGS )("Updating Refinement Zones: "
357 "update_rs time: %.3fms, "
358 "update_rs buffers: " SIZE_FORMAT ", "
359 "update_rs goal time: %.3fms",
360 update_rs_time,
361 update_rs_processed_buffers,
362 goal_ms);
363
364 _green_zone = calc_new_green_zone(_green_zone,
365 update_rs_time,
366 update_rs_processed_buffers,
367 goal_ms);
368 _yellow_zone = calc_new_yellow_zone(_green_zone, _min_yellow_zone_size);
369 _red_zone = calc_new_red_zone(_green_zone, _yellow_zone);
370
371 assert_zone_constraints_gyr(_green_zone, _yellow_zone, _red_zone);
372 LOG_ZONES("Updated Refinement Zones: "
373 "green: " SIZE_FORMAT ", "
374 "yellow: " SIZE_FORMAT ", "
375 "red: " SIZE_FORMAT,
376 _green_zone, _yellow_zone, _red_zone);
377 }
378
379 void G1ConcurrentRefine::adjust(double update_rs_time,
380 size_t update_rs_processed_buffers,
381 double goal_ms) {
382 G1DirtyCardQueueSet& dcqs = G1BarrierSet::dirty_card_queue_set();
383
384 if (G1UseAdaptiveConcRefinement) {
385 update_zones(update_rs_time, update_rs_processed_buffers, goal_ms);
386
387 // Change the barrier params
388 if (max_num_threads() == 0) {
389 // Disable dcqs notification when there are no threads to notify.
390 dcqs.set_process_completed_buffers_threshold(G1DirtyCardQueueSet::ProcessCompletedBuffersThresholdNever);
391 } else {
392 // Worker 0 is the primary; wakeup is via dcqs notification.
393 STATIC_ASSERT(max_yellow_zone <= INT_MAX);
394 size_t activate = activation_threshold(0);
395 dcqs.set_process_completed_buffers_threshold(activate);
396 }
397 dcqs.set_max_completed_buffers(red_zone());
398 }
399
400 size_t curr_queue_size = dcqs.completed_buffers_num();
401 if ((dcqs.max_completed_buffers() > 0) &&
402 (curr_queue_size >= yellow_zone())) {
403 dcqs.set_completed_buffers_padding(curr_queue_size);
404 } else {
405 dcqs.set_completed_buffers_padding(0);
406 }
407 dcqs.notify_if_necessary();
408 }
409
410 size_t G1ConcurrentRefine::activation_threshold(uint worker_id) const {
411 Thresholds thresholds = calc_thresholds(_green_zone, _yellow_zone, worker_id);
412 return activation_level(thresholds);
413 }
414
415 size_t G1ConcurrentRefine::deactivation_threshold(uint worker_id) const {
416 Thresholds thresholds = calc_thresholds(_green_zone, _yellow_zone, worker_id);
417 return deactivation_level(thresholds);
418 }
419
420 uint G1ConcurrentRefine::worker_id_offset() {
421 return G1DirtyCardQueueSet::num_par_ids();
422 }
423
424 void G1ConcurrentRefine::maybe_activate_more_threads(uint worker_id, size_t num_cur_buffers) {
425 if (num_cur_buffers > activation_threshold(worker_id + 1)) {
426 _thread_control.maybe_activate_next(worker_id);
427 }
428 }
429
430 bool G1ConcurrentRefine::do_refinement_step(uint worker_id) {
431 G1DirtyCardQueueSet& dcqs = G1BarrierSet::dirty_card_queue_set();
432
433 size_t curr_buffer_num = dcqs.completed_buffers_num();
434 // If the number of the buffers falls down into the yellow zone,
435 // that means that the transition period after the evacuation pause has ended.
436 // Since the value written to the DCQS is the same for all threads, there is no
437 // need to synchronize.
438 if (dcqs.completed_buffers_padding() > 0 && curr_buffer_num <= yellow_zone()) {
439 dcqs.set_completed_buffers_padding(0);
440 }
441
442 maybe_activate_more_threads(worker_id, curr_buffer_num);
443
444 // Process the next buffer, if there are enough left.
445 return dcqs.refine_completed_buffer_concurrently(worker_id + worker_id_offset(),
446 deactivation_threshold(worker_id));
447 }