1 /*
2 * Copyright (c) 2001, 2018, 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 "logging/log.hpp"
30 #include "memory/allocation.inline.hpp"
31 #include "runtime/java.hpp"
32 #include "runtime/thread.hpp"
33 #include "utilities/debug.hpp"
34 #include "utilities/globalDefinitions.hpp"
35 #include "utilities/pair.hpp"
36 #include <math.h>
37
38 G1ConcurrentRefineThread* G1ConcurrentRefineThreadControl::create_refinement_thread(uint worker_id, bool initializing) {
39 G1ConcurrentRefineThread* result = NULL;
40 if (initializing || !InjectGCWorkerCreationFailure) {
41 result = new G1ConcurrentRefineThread(_cr, worker_id);
42 }
43 if (result == NULL || result->osthread() == NULL) {
44 log_warning(gc)("Failed to create refinement thread %u, no more %s",
45 worker_id,
46 result == NULL ? "memory" : "OS threads");
47 }
48 return result;
49 }
50
51 G1ConcurrentRefineThreadControl::G1ConcurrentRefineThreadControl() :
52 _cr(NULL),
53 _threads(NULL),
54 _num_max_threads(0)
55 {
56 }
57
58 G1ConcurrentRefineThreadControl::~G1ConcurrentRefineThreadControl() {
59 for (uint i = 0; i < _num_max_threads; i++) {
60 G1ConcurrentRefineThread* t = _threads[i];
61 if (t != NULL) {
62 delete t;
63 }
64 }
65 FREE_C_HEAP_ARRAY(G1ConcurrentRefineThread*, _threads);
66 }
67
68 jint G1ConcurrentRefineThreadControl::initialize(G1ConcurrentRefine* cr, uint num_max_threads) {
69 assert(cr != NULL, "G1ConcurrentRefine must not be NULL");
70 _cr = cr;
71 _num_max_threads = num_max_threads;
72
73 _threads = NEW_C_HEAP_ARRAY_RETURN_NULL(G1ConcurrentRefineThread*, num_max_threads, mtGC);
74 if (_threads == NULL) {
75 vm_shutdown_during_initialization("Could not allocate thread holder array.");
76 return JNI_ENOMEM;
77 }
78
79 for (uint i = 0; i < num_max_threads; i++) {
80 if (UseDynamicNumberOfGCThreads && i != 0 /* Always start first thread. */) {
81 _threads[i] = NULL;
82 } else {
83 _threads[i] = create_refinement_thread(i, true);
84 if (_threads[i] == NULL) {
85 vm_shutdown_during_initialization("Could not allocate refinement threads.");
86 return JNI_ENOMEM;
87 }
88 }
89 }
90 return JNI_OK;
91 }
92
93 void G1ConcurrentRefineThreadControl::maybe_activate_next(uint cur_worker_id) {
94 assert(cur_worker_id < _num_max_threads,
95 "Activating another thread from %u not allowed since there can be at most %u",
96 cur_worker_id, _num_max_threads);
97 if (cur_worker_id == (_num_max_threads - 1)) {
98 // Already the last thread, there is no more thread to activate.
99 return;
100 }
101
102 uint worker_id = cur_worker_id + 1;
103 G1ConcurrentRefineThread* thread_to_activate = _threads[worker_id];
104 if (thread_to_activate == NULL) {
105 // Still need to create the thread...
106 _threads[worker_id] = create_refinement_thread(worker_id, false);
107 thread_to_activate = _threads[worker_id];
108 }
109 if (thread_to_activate != NULL && !thread_to_activate->is_active()) {
110 thread_to_activate->activate();
111 }
112 }
113
114 void G1ConcurrentRefineThreadControl::print_on(outputStream* st) const {
115 for (uint i = 0; i < _num_max_threads; ++i) {
116 if (_threads[i] != NULL) {
117 _threads[i]->print_on(st);
118 st->cr();
119 }
120 }
121 }
122
123 void G1ConcurrentRefineThreadControl::worker_threads_do(ThreadClosure* tc) {
124 for (uint i = 0; i < _num_max_threads; i++) {
125 if (_threads[i] != NULL) {
126 tc->do_thread(_threads[i]);
127 }
128 }
129 }
130
131 void G1ConcurrentRefineThreadControl::stop() {
132 for (uint i = 0; i < _num_max_threads; i++) {
133 if (_threads[i] != NULL) {
134 _threads[i]->stop();
135 }
136 }
137 }
138
139 // Arbitrary but large limits, to simplify some of the zone calculations.
140 // The general idea is to allow expressions like
141 // MIN2(x OP y, max_XXX_zone)
142 // without needing to check for overflow in "x OP y", because the
143 // ranges for x and y have been restricted.
144 STATIC_ASSERT(sizeof(LP64_ONLY(jint) NOT_LP64(jshort)) <= (sizeof(size_t)/2));
145 const size_t max_yellow_zone = LP64_ONLY(max_jint) NOT_LP64(max_jshort);
146 const size_t max_green_zone = max_yellow_zone / 2;
147 const size_t max_red_zone = INT_MAX; // For dcqs.set_max_completed_buffers.
148 STATIC_ASSERT(max_yellow_zone <= max_red_zone);
149
150 // Range check assertions for green zone values.
151 #define assert_zone_constraints_g(green) \
152 do { \
153 size_t azc_g_green = (green); \
154 assert(azc_g_green <= max_green_zone, \
155 "green exceeds max: " SIZE_FORMAT, azc_g_green); \
156 } while (0)
157
158 // Range check assertions for green and yellow zone values.
159 #define assert_zone_constraints_gy(green, yellow) \
160 do { \
161 size_t azc_gy_green = (green); \
162 size_t azc_gy_yellow = (yellow); \
163 assert_zone_constraints_g(azc_gy_green); \
164 assert(azc_gy_yellow <= max_yellow_zone, \
165 "yellow exceeds max: " SIZE_FORMAT, azc_gy_yellow); \
166 assert(azc_gy_green <= azc_gy_yellow, \
167 "green (" SIZE_FORMAT ") exceeds yellow (" SIZE_FORMAT ")", \
168 azc_gy_green, azc_gy_yellow); \
169 } while (0)
170
171 // Range check assertions for green, yellow, and red zone values.
172 #define assert_zone_constraints_gyr(green, yellow, red) \
173 do { \
174 size_t azc_gyr_green = (green); \
175 size_t azc_gyr_yellow = (yellow); \
176 size_t azc_gyr_red = (red); \
177 assert_zone_constraints_gy(azc_gyr_green, azc_gyr_yellow); \
178 assert(azc_gyr_red <= max_red_zone, \
179 "red exceeds max: " SIZE_FORMAT, azc_gyr_red); \
180 assert(azc_gyr_yellow <= azc_gyr_red, \
181 "yellow (" SIZE_FORMAT ") exceeds red (" SIZE_FORMAT ")", \
182 azc_gyr_yellow, azc_gyr_red); \
183 } while (0)
184
185 // Logging tag sequence for refinement control updates.
186 #define CTRL_TAGS gc, ergo, refine
187
188 // For logging zone values, ensuring consistency of level and tags.
189 #define LOG_ZONES(...) log_debug( CTRL_TAGS )(__VA_ARGS__)
190
191 // Package for pair of refinement thread activation and deactivation
192 // thresholds. The activation and deactivation levels are resp. the first
193 // and second values of the pair.
194 typedef Pair<size_t, size_t> Thresholds;
195 inline size_t activation_level(const Thresholds& t) { return t.first; }
196 inline size_t deactivation_level(const Thresholds& t) { return t.second; }
197
198 static Thresholds calc_thresholds(size_t green_zone,
199 size_t yellow_zone,
200 uint worker_i) {
201 double yellow_size = yellow_zone - green_zone;
202 double step = yellow_size / G1ConcurrentRefine::max_num_threads();
203 if (worker_i == 0) {
204 // Potentially activate worker 0 more aggressively, to keep
205 // available buffers near green_zone value. When yellow_size is
206 // large we don't want to allow a full step to accumulate before
207 // doing any processing, as that might lead to significantly more
208 // than green_zone buffers to be processed by update_rs.
209 step = MIN2(step, ParallelGCThreads / 2.0);
210 }
211 size_t activate_offset = static_cast<size_t>(ceil(step * (worker_i + 1)));
212 size_t deactivate_offset = static_cast<size_t>(floor(step * worker_i));
213 return Thresholds(green_zone + activate_offset,
214 green_zone + deactivate_offset);
215 }
216
217 G1ConcurrentRefine::G1ConcurrentRefine(size_t green_zone,
218 size_t yellow_zone,
219 size_t red_zone,
220 size_t min_yellow_zone_size) :
221 _thread_control(),
222 _green_zone(green_zone),
223 _yellow_zone(yellow_zone),
224 _red_zone(red_zone),
225 _min_yellow_zone_size(min_yellow_zone_size)
226 {
227 assert_zone_constraints_gyr(green_zone, yellow_zone, red_zone);
228 }
229
230 jint G1ConcurrentRefine::initialize() {
231 return _thread_control.initialize(this, max_num_threads());
232 }
233
234 static size_t calc_min_yellow_zone_size() {
235 size_t step = G1ConcRefinementThresholdStep;
236 uint n_workers = G1ConcurrentRefine::max_num_threads();
237 if ((max_yellow_zone / step) < n_workers) {
238 return max_yellow_zone;
239 } else {
240 return step * n_workers;
241 }
242 }
243
244 static size_t calc_init_green_zone() {
245 size_t green = G1ConcRefinementGreenZone;
246 if (FLAG_IS_DEFAULT(G1ConcRefinementGreenZone)) {
247 green = ParallelGCThreads;
248 }
249 return MIN2(green, max_green_zone);
250 }
251
252 static size_t calc_init_yellow_zone(size_t green, size_t min_size) {
253 size_t config = G1ConcRefinementYellowZone;
254 size_t size = 0;
255 if (FLAG_IS_DEFAULT(G1ConcRefinementYellowZone)) {
256 size = green * 2;
257 } else if (green < config) {
258 size = config - green;
259 }
260 size = MAX2(size, min_size);
261 size = MIN2(size, max_yellow_zone);
262 return MIN2(green + size, max_yellow_zone);
263 }
264
265 static size_t calc_init_red_zone(size_t green, size_t yellow) {
266 size_t size = yellow - green;
267 if (!FLAG_IS_DEFAULT(G1ConcRefinementRedZone)) {
268 size_t config = G1ConcRefinementRedZone;
269 if (yellow < config) {
270 size = MAX2(size, config - yellow);
271 }
272 }
273 return MIN2(yellow + size, max_red_zone);
274 }
275
276 G1ConcurrentRefine* G1ConcurrentRefine::create(jint* ecode) {
277 size_t min_yellow_zone_size = calc_min_yellow_zone_size();
278 size_t green_zone = calc_init_green_zone();
279 size_t yellow_zone = calc_init_yellow_zone(green_zone, min_yellow_zone_size);
280 size_t red_zone = calc_init_red_zone(green_zone, yellow_zone);
281
282 LOG_ZONES("Initial Refinement Zones: "
283 "green: " SIZE_FORMAT ", "
284 "yellow: " SIZE_FORMAT ", "
285 "red: " SIZE_FORMAT ", "
286 "min yellow size: " SIZE_FORMAT,
287 green_zone, yellow_zone, red_zone, min_yellow_zone_size);
288
289 G1ConcurrentRefine* cr = new G1ConcurrentRefine(green_zone,
290 yellow_zone,
291 red_zone,
292 min_yellow_zone_size);
293
294 if (cr == NULL) {
295 *ecode = JNI_ENOMEM;
296 vm_shutdown_during_initialization("Could not create G1ConcurrentRefine");
297 return NULL;
298 }
299
300 *ecode = cr->initialize();
301 return cr;
302 }
303
304 void G1ConcurrentRefine::stop() {
305 _thread_control.stop();
306 }
307
308 G1ConcurrentRefine::~G1ConcurrentRefine() {
309 }
310
311 void G1ConcurrentRefine::threads_do(ThreadClosure *tc) {
312 _thread_control.worker_threads_do(tc);
313 }
314
315 uint G1ConcurrentRefine::max_num_threads() {
316 return G1ConcRefinementThreads;
317 }
318
319 void G1ConcurrentRefine::print_threads_on(outputStream* st) const {
320 _thread_control.print_on(st);
321 }
322
323 static size_t calc_new_green_zone(size_t green,
324 double update_rs_time,
325 size_t update_rs_processed_buffers,
326 double goal_ms) {
327 // Adjust green zone based on whether we're meeting the time goal.
328 // Limit to max_green_zone.
329 const double inc_k = 1.1, dec_k = 0.9;
330 if (update_rs_time > goal_ms) {
331 if (green > 0) {
332 green = static_cast<size_t>(green * dec_k);
333 }
334 } else if (update_rs_time < goal_ms &&
335 update_rs_processed_buffers > green) {
336 green = static_cast<size_t>(MAX2(green * inc_k, green + 1.0));
337 green = MIN2(green, max_green_zone);
338 }
339 return green;
340 }
341
342 static size_t calc_new_yellow_zone(size_t green, size_t min_yellow_size) {
343 size_t size = green * 2;
344 size = MAX2(size, min_yellow_size);
345 return MIN2(green + size, max_yellow_zone);
346 }
347
348 static size_t calc_new_red_zone(size_t green, size_t yellow) {
349 return MIN2(yellow + (yellow - green), max_red_zone);
350 }
351
352 void G1ConcurrentRefine::update_zones(double update_rs_time,
353 size_t update_rs_processed_buffers,
354 double goal_ms) {
355 log_trace( CTRL_TAGS )("Updating Refinement Zones: "
356 "update_rs time: %.3fms, "
357 "update_rs buffers: " SIZE_FORMAT ", "
358 "update_rs goal time: %.3fms",
359 update_rs_time,
360 update_rs_processed_buffers,
361 goal_ms);
362
363 _green_zone = calc_new_green_zone(_green_zone,
364 update_rs_time,
365 update_rs_processed_buffers,
366 goal_ms);
367 _yellow_zone = calc_new_yellow_zone(_green_zone, _min_yellow_zone_size);
368 _red_zone = calc_new_red_zone(_green_zone, _yellow_zone);
369
370 assert_zone_constraints_gyr(_green_zone, _yellow_zone, _red_zone);
371 LOG_ZONES("Updated Refinement Zones: "
372 "green: " SIZE_FORMAT ", "
373 "yellow: " SIZE_FORMAT ", "
374 "red: " SIZE_FORMAT,
375 _green_zone, _yellow_zone, _red_zone);
376 }
377
378 void G1ConcurrentRefine::adjust(double update_rs_time,
379 size_t update_rs_processed_buffers,
380 double goal_ms) {
381 DirtyCardQueueSet& dcqs = G1BarrierSet::dirty_card_queue_set();
382
383 if (G1UseAdaptiveConcRefinement) {
384 update_zones(update_rs_time, update_rs_processed_buffers, goal_ms);
385
386 // Change the barrier params
387 if (max_num_threads() == 0) {
388 // Disable dcqs notification when there are no threads to notify.
389 dcqs.set_process_completed_buffers_threshold(DirtyCardQueueSet::ProcessCompletedBuffersThresholdNever);
390 } else {
391 // Worker 0 is the primary; wakeup is via dcqs notification.
392 STATIC_ASSERT(max_yellow_zone <= INT_MAX);
393 size_t activate = activation_threshold(0);
394 dcqs.set_process_completed_buffers_threshold(activate);
395 }
396 dcqs.set_max_completed_buffers(red_zone());
397 }
398
399 size_t curr_queue_size = dcqs.completed_buffers_num();
400 if ((dcqs.max_completed_buffers() > 0) &&
401 (curr_queue_size >= yellow_zone())) {
402 dcqs.set_completed_buffers_padding(curr_queue_size);
403 } else {
404 dcqs.set_completed_buffers_padding(0);
405 }
406 dcqs.notify_if_necessary();
407 }
408
409 size_t G1ConcurrentRefine::activation_threshold(uint worker_id) const {
410 Thresholds thresholds = calc_thresholds(_green_zone, _yellow_zone, worker_id);
411 return activation_level(thresholds);
412 }
413
414 size_t G1ConcurrentRefine::deactivation_threshold(uint worker_id) const {
415 Thresholds thresholds = calc_thresholds(_green_zone, _yellow_zone, worker_id);
416 return deactivation_level(thresholds);
417 }
418
419 uint G1ConcurrentRefine::worker_id_offset() {
420 return DirtyCardQueueSet::num_par_ids();
421 }
422
423 void G1ConcurrentRefine::maybe_activate_more_threads(uint worker_id, size_t num_cur_buffers) {
424 if (num_cur_buffers > activation_threshold(worker_id + 1)) {
425 _thread_control.maybe_activate_next(worker_id);
426 }
427 }
428
429 bool G1ConcurrentRefine::do_refinement_step(uint worker_id) {
430 DirtyCardQueueSet& dcqs = G1BarrierSet::dirty_card_queue_set();
431
432 size_t curr_buffer_num = dcqs.completed_buffers_num();
433 // If the number of the buffers falls down into the yellow zone,
434 // that means that the transition period after the evacuation pause has ended.
435 // Since the value written to the DCQS is the same for all threads, there is no
436 // need to synchronize.
437 if (dcqs.completed_buffers_padding() > 0 && curr_buffer_num <= yellow_zone()) {
438 dcqs.set_completed_buffers_padding(0);
439 }
440
441 maybe_activate_more_threads(worker_id, curr_buffer_num);
442
443 // Process the next buffer, if there are enough left.
444 return dcqs.refine_completed_buffer_concurrently(worker_id + worker_id_offset(),
445 deactivation_threshold(worker_id));
446 }