1 /*
2 * Copyright (c) 2010, 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 "compiler/compileBroker.hpp"
27 #include "compiler/compilerOracle.hpp"
28 #include "memory/resourceArea.hpp"
29 #include "runtime/arguments.hpp"
30 #include "runtime/handles.inline.hpp"
31 #include "runtime/safepoint.hpp"
32 #include "runtime/safepointVerifiers.hpp"
33 #include "runtime/tieredThresholdPolicy.hpp"
34 #include "code/scopeDesc.hpp"
35 #include "oops/method.inline.hpp"
36 #if INCLUDE_JVMCI
37 #include "jvmci/jvmci.hpp"
38 #endif
39
40 #ifdef TIERED
41
42 #include "c1/c1_Compiler.hpp"
43 #include "opto/c2compiler.hpp"
44
45 template<CompLevel level>
46 bool TieredThresholdPolicy::call_predicate_helper(int i, int b, double scale, Method* method) {
47 double threshold_scaling;
48 if (CompilerOracle::has_option_value(method, "CompileThresholdScaling", threshold_scaling)) {
49 scale *= threshold_scaling;
50 }
51 switch(level) {
52 case CompLevel_aot:
53 return (i >= Tier3AOTInvocationThreshold * scale) ||
54 (i >= Tier3AOTMinInvocationThreshold * scale && i + b >= Tier3AOTCompileThreshold * scale);
55 case CompLevel_none:
56 case CompLevel_limited_profile:
57 return (i >= Tier3InvocationThreshold * scale) ||
58 (i >= Tier3MinInvocationThreshold * scale && i + b >= Tier3CompileThreshold * scale);
59 case CompLevel_full_profile:
60 return (i >= Tier4InvocationThreshold * scale) ||
61 (i >= Tier4MinInvocationThreshold * scale && i + b >= Tier4CompileThreshold * scale);
62 }
63 return true;
64 }
65
66 template<CompLevel level>
67 bool TieredThresholdPolicy::loop_predicate_helper(int i, int b, double scale, Method* method) {
68 double threshold_scaling;
69 if (CompilerOracle::has_option_value(method, "CompileThresholdScaling", threshold_scaling)) {
70 scale *= threshold_scaling;
71 }
72 switch(level) {
73 case CompLevel_aot:
74 return b >= Tier3AOTBackEdgeThreshold * scale;
75 case CompLevel_none:
76 case CompLevel_limited_profile:
77 return b >= Tier3BackEdgeThreshold * scale;
78 case CompLevel_full_profile:
79 return b >= Tier4BackEdgeThreshold * scale;
80 }
81 return true;
82 }
83
84 // Simple methods are as good being compiled with C1 as C2.
85 // Determine if a given method is such a case.
86 bool TieredThresholdPolicy::is_trivial(Method* method) {
87 if (method->is_accessor() ||
88 method->is_constant_getter()) {
89 return true;
90 }
91 return false;
92 }
93
94 CompLevel TieredThresholdPolicy::comp_level(Method* method) {
95 CompiledMethod *nm = method->code();
96 if (nm != NULL && nm->is_in_use()) {
97 return (CompLevel)nm->comp_level();
98 }
99 return CompLevel_none;
100 }
101
102 void TieredThresholdPolicy::print_counters(const char* prefix, const methodHandle& mh) {
103 int invocation_count = mh->invocation_count();
104 int backedge_count = mh->backedge_count();
105 MethodData* mdh = mh->method_data();
106 int mdo_invocations = 0, mdo_backedges = 0;
107 int mdo_invocations_start = 0, mdo_backedges_start = 0;
108 if (mdh != NULL) {
109 mdo_invocations = mdh->invocation_count();
110 mdo_backedges = mdh->backedge_count();
111 mdo_invocations_start = mdh->invocation_count_start();
112 mdo_backedges_start = mdh->backedge_count_start();
113 }
114 tty->print(" %stotal=%d,%d %smdo=%d(%d),%d(%d)", prefix,
115 invocation_count, backedge_count, prefix,
116 mdo_invocations, mdo_invocations_start,
117 mdo_backedges, mdo_backedges_start);
118 tty->print(" %smax levels=%d,%d", prefix,
119 mh->highest_comp_level(), mh->highest_osr_comp_level());
120 }
121
122 // Print an event.
123 void TieredThresholdPolicy::print_event(EventType type, const methodHandle& mh, const methodHandle& imh,
124 int bci, CompLevel level) {
125 bool inlinee_event = mh() != imh();
126
127 ttyLocker tty_lock;
128 tty->print("%lf: [", os::elapsedTime());
129
130 switch(type) {
131 case CALL:
132 tty->print("call");
133 break;
134 case LOOP:
135 tty->print("loop");
136 break;
137 case COMPILE:
138 tty->print("compile");
139 break;
140 case REMOVE_FROM_QUEUE:
141 tty->print("remove-from-queue");
142 break;
143 case UPDATE_IN_QUEUE:
144 tty->print("update-in-queue");
145 break;
146 case REPROFILE:
147 tty->print("reprofile");
148 break;
149 case MAKE_NOT_ENTRANT:
150 tty->print("make-not-entrant");
151 break;
152 default:
153 tty->print("unknown");
154 }
155
156 tty->print(" level=%d ", level);
157
158 ResourceMark rm;
159 char *method_name = mh->name_and_sig_as_C_string();
160 tty->print("[%s", method_name);
161 if (inlinee_event) {
162 char *inlinee_name = imh->name_and_sig_as_C_string();
163 tty->print(" [%s]] ", inlinee_name);
164 }
165 else tty->print("] ");
166 tty->print("@%d queues=%d,%d", bci, CompileBroker::queue_size(CompLevel_full_profile),
167 CompileBroker::queue_size(CompLevel_full_optimization));
168
169 print_specific(type, mh, imh, bci, level);
170
171 if (type != COMPILE) {
172 print_counters("", mh);
173 if (inlinee_event) {
174 print_counters("inlinee ", imh);
175 }
176 tty->print(" compilable=");
177 bool need_comma = false;
178 if (!mh->is_not_compilable(CompLevel_full_profile)) {
179 tty->print("c1");
180 need_comma = true;
181 }
182 if (!mh->is_not_osr_compilable(CompLevel_full_profile)) {
183 if (need_comma) tty->print(",");
184 tty->print("c1-osr");
185 need_comma = true;
186 }
187 if (!mh->is_not_compilable(CompLevel_full_optimization)) {
188 if (need_comma) tty->print(",");
189 tty->print("c2");
190 need_comma = true;
191 }
192 if (!mh->is_not_osr_compilable(CompLevel_full_optimization)) {
193 if (need_comma) tty->print(",");
194 tty->print("c2-osr");
195 }
196 tty->print(" status=");
197 if (mh->queued_for_compilation()) {
198 tty->print("in-queue");
199 } else tty->print("idle");
200 }
201 tty->print_cr("]");
202 }
203
204 void TieredThresholdPolicy::initialize() {
205 int count = CICompilerCount;
206 bool c1_only = TieredStopAtLevel < CompLevel_full_optimization;
207 #ifdef _LP64
208 // Turn on ergonomic compiler count selection
209 if (FLAG_IS_DEFAULT(CICompilerCountPerCPU) && FLAG_IS_DEFAULT(CICompilerCount)) {
210 FLAG_SET_DEFAULT(CICompilerCountPerCPU, true);
211 }
212 if (CICompilerCountPerCPU) {
213 // Simple log n seems to grow too slowly for tiered, try something faster: log n * log log n
214 int log_cpu = log2_int(os::active_processor_count());
215 int loglog_cpu = log2_int(MAX2(log_cpu, 1));
216 count = MAX2(log_cpu * loglog_cpu * 3 / 2, 2);
217 // Make sure there is enough space in the code cache to hold all the compiler buffers
218 size_t c1_size = Compiler::code_buffer_size();
219 size_t c2_size = C2Compiler::initial_code_buffer_size();
220 size_t buffer_size = c1_only ? c1_size : (c1_size/3 + 2*c2_size/3);
221 int max_count = (ReservedCodeCacheSize - (CodeCacheMinimumUseSpace DEBUG_ONLY(* 3))) / (int)buffer_size;
222 if (count > max_count) {
223 // Lower the compiler count such that all buffers fit into the code cache
224 count = MAX2(max_count, c1_only ? 1 : 2);
225 }
226 FLAG_SET_ERGO(intx, CICompilerCount, count);
227 }
228 #else
229 // On 32-bit systems, the number of compiler threads is limited to 3.
230 // On these systems, the virtual address space available to the JVM
231 // is usually limited to 2-4 GB (the exact value depends on the platform).
232 // As the compilers (especially C2) can consume a large amount of
233 // memory, scaling the number of compiler threads with the number of
234 // available cores can result in the exhaustion of the address space
235 /// available to the VM and thus cause the VM to crash.
236 if (FLAG_IS_DEFAULT(CICompilerCount)) {
237 count = 3;
238 FLAG_SET_ERGO(intx, CICompilerCount, count);
239 }
240 #endif
241
242 if (c1_only) {
243 // No C2 compiler thread required
244 set_c1_count(count);
245 } else {
246 set_c1_count(MAX2(count / 3, 1));
247 set_c2_count(MAX2(count - c1_count(), 1));
248 }
249 assert(count == c1_count() + c2_count(), "inconsistent compiler thread count");
250
251 // Some inlining tuning
252 #ifdef X86
253 if (FLAG_IS_DEFAULT(InlineSmallCode)) {
254 FLAG_SET_DEFAULT(InlineSmallCode, 2000);
255 }
256 #endif
257
258 #if defined SPARC || defined AARCH64
259 if (FLAG_IS_DEFAULT(InlineSmallCode)) {
260 FLAG_SET_DEFAULT(InlineSmallCode, 2500);
261 }
262 #endif
263
264 set_increase_threshold_at_ratio();
265 set_start_time(os::javaTimeMillis());
266 }
267
268 void TieredThresholdPolicy::set_carry_if_necessary(InvocationCounter *counter) {
269 if (!counter->carry() && counter->count() > InvocationCounter::count_limit / 2) {
270 counter->set_carry_flag();
271 }
272 }
273
274 // Set carry flags on the counters if necessary
275 void TieredThresholdPolicy::handle_counter_overflow(Method* method) {
276 MethodCounters *mcs = method->method_counters();
277 if (mcs != NULL) {
278 set_carry_if_necessary(mcs->invocation_counter());
279 set_carry_if_necessary(mcs->backedge_counter());
280 }
281 MethodData* mdo = method->method_data();
282 if (mdo != NULL) {
283 set_carry_if_necessary(mdo->invocation_counter());
284 set_carry_if_necessary(mdo->backedge_counter());
285 }
286 }
287
288 // Called with the queue locked and with at least one element
289 CompileTask* TieredThresholdPolicy::select_task(CompileQueue* compile_queue) {
290 CompileTask *max_blocking_task = NULL;
291 CompileTask *max_task = NULL;
292 Method* max_method = NULL;
293 jlong t = os::javaTimeMillis();
294 // Iterate through the queue and find a method with a maximum rate.
295 for (CompileTask* task = compile_queue->first(); task != NULL;) {
296 CompileTask* next_task = task->next();
297 Method* method = task->method();
298 // If a method was unloaded or has been stale for some time, remove it from the queue.
299 // Blocking tasks and tasks submitted from whitebox API don't become stale
300 if (task->is_unloaded() || (task->can_become_stale() && is_stale(t, TieredCompileTaskTimeout, method) && !is_old(method))) {
301 if (!task->is_unloaded()) {
302 if (PrintTieredEvents) {
303 print_event(REMOVE_FROM_QUEUE, method, method, task->osr_bci(), (CompLevel) task->comp_level());
304 }
305 method->clear_queued_for_compilation();
306 }
307 compile_queue->remove_and_mark_stale(task);
308 task = next_task;
309 continue;
310 }
311 update_rate(t, method);
312 if (max_task == NULL || compare_methods(method, max_method)) {
313 // Select a method with the highest rate
314 max_task = task;
315 max_method = method;
316 }
317
318 if (task->is_blocking()) {
319 if (max_blocking_task == NULL || compare_methods(method, max_blocking_task->method())) {
320 max_blocking_task = task;
321 }
322 }
323
324 task = next_task;
325 }
326
327 if (max_blocking_task != NULL) {
328 // In blocking compilation mode, the CompileBroker will make
329 // compilations submitted by a JVMCI compiler thread non-blocking. These
330 // compilations should be scheduled after all blocking compilations
331 // to service non-compiler related compilations sooner and reduce the
332 // chance of such compilations timing out.
333 max_task = max_blocking_task;
334 max_method = max_task->method();
335 }
336
337 if (max_task != NULL && max_task->comp_level() == CompLevel_full_profile &&
338 TieredStopAtLevel > CompLevel_full_profile &&
339 max_method != NULL && is_method_profiled(max_method)) {
340 max_task->set_comp_level(CompLevel_limited_profile);
341 if (PrintTieredEvents) {
342 print_event(UPDATE_IN_QUEUE, max_method, max_method, max_task->osr_bci(), (CompLevel)max_task->comp_level());
343 }
344 }
345
346 return max_task;
347 }
348
349 void TieredThresholdPolicy::reprofile(ScopeDesc* trap_scope, bool is_osr) {
350 for (ScopeDesc* sd = trap_scope;; sd = sd->sender()) {
351 if (PrintTieredEvents) {
352 methodHandle mh(sd->method());
353 print_event(REPROFILE, mh, mh, InvocationEntryBci, CompLevel_none);
354 }
355 MethodData* mdo = sd->method()->method_data();
356 if (mdo != NULL) {
357 mdo->reset_start_counters();
358 }
359 if (sd->is_top()) break;
360 }
361 }
362
363 nmethod* TieredThresholdPolicy::event(const methodHandle& method, const methodHandle& inlinee,
364 int branch_bci, int bci, CompLevel comp_level, CompiledMethod* nm, JavaThread* thread) {
365 if (comp_level == CompLevel_none &&
366 JvmtiExport::can_post_interpreter_events() &&
367 thread->is_interp_only_mode()) {
368 return NULL;
369 }
370 if (ReplayCompiles) {
371 // Don't trigger other compiles in testing mode
372 return NULL;
373 }
374
375 handle_counter_overflow(method());
376 if (method() != inlinee()) {
377 handle_counter_overflow(inlinee());
378 }
379
380 if (PrintTieredEvents) {
381 print_event(bci == InvocationEntryBci ? CALL : LOOP, method, inlinee, bci, comp_level);
382 }
383
384 if (bci == InvocationEntryBci) {
385 method_invocation_event(method, inlinee, comp_level, nm, thread);
386 } else {
387 // method == inlinee if the event originated in the main method
388 method_back_branch_event(method, inlinee, bci, comp_level, nm, thread);
389 // Check if event led to a higher level OSR compilation
390 nmethod* osr_nm = inlinee->lookup_osr_nmethod_for(bci, comp_level, false);
391 if (osr_nm != NULL && osr_nm->comp_level() > comp_level) {
392 // Perform OSR with new nmethod
393 return osr_nm;
394 }
395 }
396 return NULL;
397 }
398
399 // Check if the method can be compiled, change level if necessary
400 void TieredThresholdPolicy::compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) {
401 assert(level <= TieredStopAtLevel, "Invalid compilation level");
402 if (level == CompLevel_none) {
403 return;
404 }
405 if (level == CompLevel_aot) {
406 if (mh->has_aot_code()) {
407 if (PrintTieredEvents) {
408 print_event(COMPILE, mh, mh, bci, level);
409 }
410 MutexLocker ml(Compile_lock);
411 NoSafepointVerifier nsv;
412 if (mh->has_aot_code() && mh->code() != mh->aot_code()) {
413 mh->aot_code()->make_entrant();
414 if (mh->has_compiled_code()) {
415 mh->code()->make_not_entrant();
416 }
417 Method::set_code(mh, mh->aot_code());
418 }
419 }
420 return;
421 }
422
423 // Check if the method can be compiled. If it cannot be compiled with C1, continue profiling
424 // in the interpreter and then compile with C2 (the transition function will request that,
425 // see common() ). If the method cannot be compiled with C2 but still can with C1, compile it with
426 // pure C1.
427 if (!can_be_compiled(mh, level)) {
428 if (level == CompLevel_full_optimization && can_be_compiled(mh, CompLevel_simple)) {
429 compile(mh, bci, CompLevel_simple, thread);
430 }
431 return;
432 }
433 if (bci != InvocationEntryBci && mh->is_not_osr_compilable(level)) {
434 return;
435 }
436 if (!CompileBroker::compilation_is_in_queue(mh)) {
437 if (PrintTieredEvents) {
438 print_event(COMPILE, mh, mh, bci, level);
439 }
440 submit_compile(mh, bci, level, thread);
441 }
442 }
443
444 // Update the rate and submit compile
445 void TieredThresholdPolicy::submit_compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) {
446 int hot_count = (bci == InvocationEntryBci) ? mh->invocation_count() : mh->backedge_count();
447 update_rate(os::javaTimeMillis(), mh());
448 CompileBroker::compile_method(mh, bci, level, mh, hot_count, CompileTask::Reason_Tiered, thread);
449 }
450
451 // Print an event.
452 void TieredThresholdPolicy::print_specific(EventType type, const methodHandle& mh, const methodHandle& imh,
453 int bci, CompLevel level) {
454 tty->print(" rate=");
455 if (mh->prev_time() == 0) tty->print("n/a");
456 else tty->print("%f", mh->rate());
457
458 tty->print(" k=%.2lf,%.2lf", threshold_scale(CompLevel_full_profile, Tier3LoadFeedback),
459 threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback));
460
461 }
462
463 // update_rate() is called from select_task() while holding a compile queue lock.
464 void TieredThresholdPolicy::update_rate(jlong t, Method* m) {
465 // Skip update if counters are absent.
466 // Can't allocate them since we are holding compile queue lock.
467 if (m->method_counters() == NULL) return;
468
469 if (is_old(m)) {
470 // We don't remove old methods from the queue,
471 // so we can just zero the rate.
472 m->set_rate(0);
473 return;
474 }
475
476 // We don't update the rate if we've just came out of a safepoint.
477 // delta_s is the time since last safepoint in milliseconds.
478 jlong delta_s = t - SafepointTracing::end_of_last_safepoint_epoch_ms();
479 jlong delta_t = t - (m->prev_time() != 0 ? m->prev_time() : start_time()); // milliseconds since the last measurement
480 // How many events were there since the last time?
481 int event_count = m->invocation_count() + m->backedge_count();
482 int delta_e = event_count - m->prev_event_count();
483
484 // We should be running for at least 1ms.
485 if (delta_s >= TieredRateUpdateMinTime) {
486 // And we must've taken the previous point at least 1ms before.
487 if (delta_t >= TieredRateUpdateMinTime && delta_e > 0) {
488 m->set_prev_time(t);
489 m->set_prev_event_count(event_count);
490 m->set_rate((float)delta_e / (float)delta_t); // Rate is events per millisecond
491 } else {
492 if (delta_t > TieredRateUpdateMaxTime && delta_e == 0) {
493 // If nothing happened for 25ms, zero the rate. Don't modify prev values.
494 m->set_rate(0);
495 }
496 }
497 }
498 }
499
500 // Check if this method has been stale for a given number of milliseconds.
501 // See select_task().
502 bool TieredThresholdPolicy::is_stale(jlong t, jlong timeout, Method* m) {
503 jlong delta_s = t - SafepointTracing::end_of_last_safepoint_epoch_ms();
504 jlong delta_t = t - m->prev_time();
505 if (delta_t > timeout && delta_s > timeout) {
506 int event_count = m->invocation_count() + m->backedge_count();
507 int delta_e = event_count - m->prev_event_count();
508 // Return true if there were no events.
509 return delta_e == 0;
510 }
511 return false;
512 }
513
514 // We don't remove old methods from the compile queue even if they have
515 // very low activity. See select_task().
516 bool TieredThresholdPolicy::is_old(Method* method) {
517 return method->invocation_count() > 50000 || method->backedge_count() > 500000;
518 }
519
520 double TieredThresholdPolicy::weight(Method* method) {
521 return (double)(method->rate() + 1) *
522 (method->invocation_count() + 1) * (method->backedge_count() + 1);
523 }
524
525 // Apply heuristics and return true if x should be compiled before y
526 bool TieredThresholdPolicy::compare_methods(Method* x, Method* y) {
527 if (x->highest_comp_level() > y->highest_comp_level()) {
528 // recompilation after deopt
529 return true;
530 } else
531 if (x->highest_comp_level() == y->highest_comp_level()) {
532 if (weight(x) > weight(y)) {
533 return true;
534 }
535 }
536 return false;
537 }
538
539 // Is method profiled enough?
540 bool TieredThresholdPolicy::is_method_profiled(Method* method) {
541 MethodData* mdo = method->method_data();
542 if (mdo != NULL) {
543 int i = mdo->invocation_count_delta();
544 int b = mdo->backedge_count_delta();
545 return call_predicate_helper<CompLevel_full_profile>(i, b, 1, method);
546 }
547 return false;
548 }
549
550 double TieredThresholdPolicy::threshold_scale(CompLevel level, int feedback_k) {
551 double queue_size = CompileBroker::queue_size(level);
552 int comp_count = compiler_count(level);
553 double k = queue_size / (feedback_k * comp_count) + 1;
554
555 // Increase C1 compile threshold when the code cache is filled more
556 // than specified by IncreaseFirstTierCompileThresholdAt percentage.
557 // The main intention is to keep enough free space for C2 compiled code
558 // to achieve peak performance if the code cache is under stress.
559 if ((TieredStopAtLevel == CompLevel_full_optimization) && (level != CompLevel_full_optimization)) {
560 double current_reverse_free_ratio = CodeCache::reverse_free_ratio(CodeCache::get_code_blob_type(level));
561 if (current_reverse_free_ratio > _increase_threshold_at_ratio) {
562 k *= exp(current_reverse_free_ratio - _increase_threshold_at_ratio);
563 }
564 }
565 return k;
566 }
567
568 // Call and loop predicates determine whether a transition to a higher
569 // compilation level should be performed (pointers to predicate functions
570 // are passed to common()).
571 // Tier?LoadFeedback is basically a coefficient that determines of
572 // how many methods per compiler thread can be in the queue before
573 // the threshold values double.
574 bool TieredThresholdPolicy::loop_predicate(int i, int b, CompLevel cur_level, Method* method) {
575 switch(cur_level) {
576 case CompLevel_aot: {
577 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
578 return loop_predicate_helper<CompLevel_aot>(i, b, k, method);
579 }
580 case CompLevel_none:
581 case CompLevel_limited_profile: {
582 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
583 return loop_predicate_helper<CompLevel_none>(i, b, k, method);
584 }
585 case CompLevel_full_profile: {
586 double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);
587 return loop_predicate_helper<CompLevel_full_profile>(i, b, k, method);
588 }
589 default:
590 return true;
591 }
592 }
593
594 bool TieredThresholdPolicy::call_predicate(int i, int b, CompLevel cur_level, Method* method) {
595 switch(cur_level) {
596 case CompLevel_aot: {
597 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
598 return call_predicate_helper<CompLevel_aot>(i, b, k, method);
599 }
600 case CompLevel_none:
601 case CompLevel_limited_profile: {
602 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
603 return call_predicate_helper<CompLevel_none>(i, b, k, method);
604 }
605 case CompLevel_full_profile: {
606 double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);
607 return call_predicate_helper<CompLevel_full_profile>(i, b, k, method);
608 }
609 default:
610 return true;
611 }
612 }
613
614 // Determine is a method is mature.
615 bool TieredThresholdPolicy::is_mature(Method* method) {
616 if (is_trivial(method)) return true;
617 MethodData* mdo = method->method_data();
618 if (mdo != NULL) {
619 int i = mdo->invocation_count();
620 int b = mdo->backedge_count();
621 double k = ProfileMaturityPercentage / 100.0;
622 return call_predicate_helper<CompLevel_full_profile>(i, b, k, method) ||
623 loop_predicate_helper<CompLevel_full_profile>(i, b, k, method);
624 }
625 return false;
626 }
627
628 // If a method is old enough and is still in the interpreter we would want to
629 // start profiling without waiting for the compiled method to arrive.
630 // We also take the load on compilers into the account.
631 bool TieredThresholdPolicy::should_create_mdo(Method* method, CompLevel cur_level) {
632 if (cur_level == CompLevel_none &&
633 CompileBroker::queue_size(CompLevel_full_optimization) <=
634 Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {
635 int i = method->invocation_count();
636 int b = method->backedge_count();
637 double k = Tier0ProfilingStartPercentage / 100.0;
638 return call_predicate_helper<CompLevel_none>(i, b, k, method) || loop_predicate_helper<CompLevel_none>(i, b, k, method);
639 }
640 return false;
641 }
642
643 // Inlining control: if we're compiling a profiled method with C1 and the callee
644 // is known to have OSRed in a C2 version, don't inline it.
645 bool TieredThresholdPolicy::should_not_inline(ciEnv* env, ciMethod* callee) {
646 CompLevel comp_level = (CompLevel)env->comp_level();
647 if (comp_level == CompLevel_full_profile ||
648 comp_level == CompLevel_limited_profile) {
649 return callee->highest_osr_comp_level() == CompLevel_full_optimization;
650 }
651 return false;
652 }
653
654 // Create MDO if necessary.
655 void TieredThresholdPolicy::create_mdo(const methodHandle& mh, JavaThread* THREAD) {
656 if (mh->is_native() ||
657 mh->is_abstract() ||
658 mh->is_accessor() ||
659 mh->is_constant_getter()) {
660 return;
661 }
662 if (mh->method_data() == NULL) {
663 Method::build_interpreter_method_data(mh, CHECK_AND_CLEAR);
664 }
665 }
666
667
668 /*
669 * Method states:
670 * 0 - interpreter (CompLevel_none)
671 * 1 - pure C1 (CompLevel_simple)
672 * 2 - C1 with invocation and backedge counting (CompLevel_limited_profile)
673 * 3 - C1 with full profiling (CompLevel_full_profile)
674 * 4 - C2 (CompLevel_full_optimization)
675 *
676 * Common state transition patterns:
677 * a. 0 -> 3 -> 4.
678 * The most common path. But note that even in this straightforward case
679 * profiling can start at level 0 and finish at level 3.
680 *
681 * b. 0 -> 2 -> 3 -> 4.
682 * This case occurs when the load on C2 is deemed too high. So, instead of transitioning
683 * into state 3 directly and over-profiling while a method is in the C2 queue we transition to
684 * level 2 and wait until the load on C2 decreases. This path is disabled for OSRs.
685 *
686 * c. 0 -> (3->2) -> 4.
687 * In this case we enqueue a method for compilation at level 3, but the C1 queue is long enough
688 * to enable the profiling to fully occur at level 0. In this case we change the compilation level
689 * of the method to 2 while the request is still in-queue, because it'll allow it to run much faster
690 * without full profiling while c2 is compiling.
691 *
692 * d. 0 -> 3 -> 1 or 0 -> 2 -> 1.
693 * After a method was once compiled with C1 it can be identified as trivial and be compiled to
694 * level 1. These transition can also occur if a method can't be compiled with C2 but can with C1.
695 *
696 * e. 0 -> 4.
697 * This can happen if a method fails C1 compilation (it will still be profiled in the interpreter)
698 * or because of a deopt that didn't require reprofiling (compilation won't happen in this case because
699 * the compiled version already exists).
700 *
701 * Note that since state 0 can be reached from any other state via deoptimization different loops
702 * are possible.
703 *
704 */
705
706 // Common transition function. Given a predicate determines if a method should transition to another level.
707 CompLevel TieredThresholdPolicy::common(Predicate p, Method* method, CompLevel cur_level, bool disable_feedback) {
708 CompLevel next_level = cur_level;
709 int i = method->invocation_count();
710 int b = method->backedge_count();
711
712 if (is_trivial(method)) {
713 next_level = CompLevel_simple;
714 } else {
715 switch(cur_level) {
716 default: break;
717 case CompLevel_aot: {
718 // If we were at full profile level, would we switch to full opt?
719 if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) {
720 next_level = CompLevel_full_optimization;
721 } else if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
722 Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
723 (this->*p)(i, b, cur_level, method))) {
724 next_level = CompLevel_full_profile;
725 }
726 }
727 break;
728 case CompLevel_none:
729 // If we were at full profile level, would we switch to full opt?
730 if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) {
731 next_level = CompLevel_full_optimization;
732 } else if ((this->*p)(i, b, cur_level, method)) {
733 #if INCLUDE_JVMCI
734 if (EnableJVMCI && UseJVMCICompiler) {
735 // Since JVMCI takes a while to warm up, its queue inevitably backs up during
736 // early VM execution. As of 2014-06-13, JVMCI's inliner assumes that the root
737 // compilation method and all potential inlinees have mature profiles (which
738 // includes type profiling). If it sees immature profiles, JVMCI's inliner
739 // can perform pathologically bad (e.g., causing OutOfMemoryErrors due to
740 // exploring/inlining too many graphs). Since a rewrite of the inliner is
741 // in progress, we simply disable the dialing back heuristic for now and will
742 // revisit this decision once the new inliner is completed.
743 next_level = CompLevel_full_profile;
744 } else
745 #endif
746 {
747 // C1-generated fully profiled code is about 30% slower than the limited profile
748 // code that has only invocation and backedge counters. The observation is that
749 // if C2 queue is large enough we can spend too much time in the fully profiled code
750 // while waiting for C2 to pick the method from the queue. To alleviate this problem
751 // we introduce a feedback on the C2 queue size. If the C2 queue is sufficiently long
752 // we choose to compile a limited profiled version and then recompile with full profiling
753 // when the load on C2 goes down.
754 if (!disable_feedback && CompileBroker::queue_size(CompLevel_full_optimization) >
755 Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {
756 next_level = CompLevel_limited_profile;
757 } else {
758 next_level = CompLevel_full_profile;
759 }
760 }
761 }
762 break;
763 case CompLevel_limited_profile:
764 if (is_method_profiled(method)) {
765 // Special case: we got here because this method was fully profiled in the interpreter.
766 next_level = CompLevel_full_optimization;
767 } else {
768 MethodData* mdo = method->method_data();
769 if (mdo != NULL) {
770 if (mdo->would_profile()) {
771 if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
772 Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
773 (this->*p)(i, b, cur_level, method))) {
774 next_level = CompLevel_full_profile;
775 }
776 } else {
777 next_level = CompLevel_full_optimization;
778 }
779 } else {
780 // If there is no MDO we need to profile
781 if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
782 Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
783 (this->*p)(i, b, cur_level, method))) {
784 next_level = CompLevel_full_profile;
785 }
786 }
787 }
788 break;
789 case CompLevel_full_profile:
790 {
791 MethodData* mdo = method->method_data();
792 if (mdo != NULL) {
793 if (mdo->would_profile()) {
794 int mdo_i = mdo->invocation_count_delta();
795 int mdo_b = mdo->backedge_count_delta();
796 if ((this->*p)(mdo_i, mdo_b, cur_level, method)) {
797 next_level = CompLevel_full_optimization;
798 }
799 } else {
800 next_level = CompLevel_full_optimization;
801 }
802 }
803 }
804 break;
805 }
806 }
807 return MIN2(next_level, (CompLevel)TieredStopAtLevel);
808 }
809
810 // Determine if a method should be compiled with a normal entry point at a different level.
811 CompLevel TieredThresholdPolicy::call_event(Method* method, CompLevel cur_level, JavaThread * thread) {
812 CompLevel osr_level = MIN2((CompLevel) method->highest_osr_comp_level(),
813 common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true));
814 CompLevel next_level = common(&TieredThresholdPolicy::call_predicate, method, cur_level);
815
816 // If OSR method level is greater than the regular method level, the levels should be
817 // equalized by raising the regular method level in order to avoid OSRs during each
818 // invocation of the method.
819 if (osr_level == CompLevel_full_optimization && cur_level == CompLevel_full_profile) {
820 MethodData* mdo = method->method_data();
821 guarantee(mdo != NULL, "MDO should not be NULL");
822 if (mdo->invocation_count() >= 1) {
823 next_level = CompLevel_full_optimization;
824 }
825 } else {
826 next_level = MAX2(osr_level, next_level);
827 }
828 #if INCLUDE_JVMCI
829 if (UseJVMCICompiler) {
830 next_level = JVMCI::adjust_comp_level(method, false, next_level, thread);
831 }
832 #endif
833 return next_level;
834 }
835
836 // Determine if we should do an OSR compilation of a given method.
837 CompLevel TieredThresholdPolicy::loop_event(Method* method, CompLevel cur_level, JavaThread* thread) {
838 CompLevel next_level = common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true);
839 if (cur_level == CompLevel_none) {
840 // If there is a live OSR method that means that we deopted to the interpreter
841 // for the transition.
842 CompLevel osr_level = MIN2((CompLevel)method->highest_osr_comp_level(), next_level);
843 if (osr_level > CompLevel_none) {
844 return osr_level;
845 }
846 }
847 #if INCLUDE_JVMCI
848 if (UseJVMCICompiler) {
849 next_level = JVMCI::adjust_comp_level(method, true, next_level, thread);
850 }
851 #endif
852 return next_level;
853 }
854
855 bool TieredThresholdPolicy::maybe_switch_to_aot(const methodHandle& mh, CompLevel cur_level, CompLevel next_level, JavaThread* thread) {
856 if (UseAOT) {
857 if (cur_level == CompLevel_full_profile || cur_level == CompLevel_none) {
858 // If the current level is full profile or interpreter and we're switching to any other level,
859 // activate the AOT code back first so that we won't waste time overprofiling.
860 compile(mh, InvocationEntryBci, CompLevel_aot, thread);
861 // Fall through for JIT compilation.
862 }
863 if (next_level == CompLevel_limited_profile && cur_level != CompLevel_aot && mh->has_aot_code()) {
864 // If the next level is limited profile, use the aot code (if there is any),
865 // since it's essentially the same thing.
866 compile(mh, InvocationEntryBci, CompLevel_aot, thread);
867 // Not need to JIT, we're done.
868 return true;
869 }
870 }
871 return false;
872 }
873
874
875 // Handle the invocation event.
876 void TieredThresholdPolicy::method_invocation_event(const methodHandle& mh, const methodHandle& imh,
877 CompLevel level, CompiledMethod* nm, JavaThread* thread) {
878 if (should_create_mdo(mh(), level)) {
879 create_mdo(mh, thread);
880 }
881 CompLevel next_level = call_event(mh(), level, thread);
882 if (next_level != level) {
883 if (maybe_switch_to_aot(mh, level, next_level, thread)) {
884 // No JITting necessary
885 return;
886 }
887 if (is_compilation_enabled() && !CompileBroker::compilation_is_in_queue(mh)) {
888 compile(mh, InvocationEntryBci, next_level, thread);
889 }
890 }
891 }
892
893 // Handle the back branch event. Notice that we can compile the method
894 // with a regular entry from here.
895 void TieredThresholdPolicy::method_back_branch_event(const methodHandle& mh, const methodHandle& imh,
896 int bci, CompLevel level, CompiledMethod* nm, JavaThread* thread) {
897 if (should_create_mdo(mh(), level)) {
898 create_mdo(mh, thread);
899 }
900 // Check if MDO should be created for the inlined method
901 if (should_create_mdo(imh(), level)) {
902 create_mdo(imh, thread);
903 }
904
905 if (is_compilation_enabled()) {
906 CompLevel next_osr_level = loop_event(imh(), level, thread);
907 CompLevel max_osr_level = (CompLevel)imh->highest_osr_comp_level();
908 // At the very least compile the OSR version
909 if (!CompileBroker::compilation_is_in_queue(imh) && (next_osr_level != level)) {
910 compile(imh, bci, next_osr_level, thread);
911 }
912
913 // Use loop event as an opportunity to also check if there's been
914 // enough calls.
915 CompLevel cur_level, next_level;
916 if (mh() != imh()) { // If there is an enclosing method
917 if (level == CompLevel_aot) {
918 // Recompile the enclosing method to prevent infinite OSRs. Stay at AOT level while it's compiling.
919 if (max_osr_level != CompLevel_none && !CompileBroker::compilation_is_in_queue(mh)) {
920 compile(mh, InvocationEntryBci, MIN2((CompLevel)TieredStopAtLevel, CompLevel_full_profile), thread);
921 }
922 } else {
923 // Current loop event level is not AOT
924 guarantee(nm != NULL, "Should have nmethod here");
925 cur_level = comp_level(mh());
926 next_level = call_event(mh(), cur_level, thread);
927
928 if (max_osr_level == CompLevel_full_optimization) {
929 // The inlinee OSRed to full opt, we need to modify the enclosing method to avoid deopts
930 bool make_not_entrant = false;
931 if (nm->is_osr_method()) {
932 // This is an osr method, just make it not entrant and recompile later if needed
933 make_not_entrant = true;
934 } else {
935 if (next_level != CompLevel_full_optimization) {
936 // next_level is not full opt, so we need to recompile the
937 // enclosing method without the inlinee
938 cur_level = CompLevel_none;
939 make_not_entrant = true;
940 }
941 }
942 if (make_not_entrant) {
943 if (PrintTieredEvents) {
944 int osr_bci = nm->is_osr_method() ? nm->osr_entry_bci() : InvocationEntryBci;
945 print_event(MAKE_NOT_ENTRANT, mh(), mh(), osr_bci, level);
946 }
947 nm->make_not_entrant();
948 }
949 }
950 // Fix up next_level if necessary to avoid deopts
951 if (next_level == CompLevel_limited_profile && max_osr_level == CompLevel_full_profile) {
952 next_level = CompLevel_full_profile;
953 }
954 if (cur_level != next_level) {
955 if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) {
956 compile(mh, InvocationEntryBci, next_level, thread);
957 }
958 }
959 }
960 } else {
961 cur_level = comp_level(mh());
962 next_level = call_event(mh(), cur_level, thread);
963 if (next_level != cur_level) {
964 if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) {
965 compile(mh, InvocationEntryBci, next_level, thread);
966 }
967 }
968 }
969 }
970 }
971
972 #endif