1 /*
2 * Copyright (c) 2010, 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 "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/safepointVerifiers.hpp"
32 #include "runtime/tieredThresholdPolicy.hpp"
33 #include "code/scopeDesc.hpp"
34 #include "oops/method.inline.hpp"
35 #if INCLUDE_JVMCI
36 #include "jvmci/jvmciRuntime.hpp"
37 #endif
38
39 #ifdef TIERED
40
41 #include "c1/c1_Compiler.hpp"
42 #include "opto/c2compiler.hpp"
43
44 template<CompLevel level>
45 bool TieredThresholdPolicy::call_predicate_helper(int i, int b, double scale, Method* method) {
46 double threshold_scaling;
47 if (CompilerOracle::has_option_value(method, "CompileThresholdScaling", threshold_scaling)) {
48 scale *= threshold_scaling;
49 }
50 switch(level) {
51 case CompLevel_aot:
52 return (i >= Tier3AOTInvocationThreshold * scale) ||
53 (i >= Tier3AOTMinInvocationThreshold * scale && i + b >= Tier3AOTCompileThreshold * scale);
54 case CompLevel_none:
55 case CompLevel_limited_profile:
56 return (i >= Tier3InvocationThreshold * scale) ||
57 (i >= Tier3MinInvocationThreshold * scale && i + b >= Tier3CompileThreshold * scale);
58 case CompLevel_full_profile:
59 return (i >= Tier4InvocationThreshold * scale) ||
60 (i >= Tier4MinInvocationThreshold * scale && i + b >= Tier4CompileThreshold * scale);
61 }
62 return true;
63 }
64
65 template<CompLevel level>
66 bool TieredThresholdPolicy::loop_predicate_helper(int i, int b, double scale, Method* method) {
67 double threshold_scaling;
68 if (CompilerOracle::has_option_value(method, "CompileThresholdScaling", threshold_scaling)) {
69 scale *= threshold_scaling;
70 }
71 switch(level) {
72 case CompLevel_aot:
73 return b >= Tier3AOTBackEdgeThreshold * scale;
74 case CompLevel_none:
75 case CompLevel_limited_profile:
76 return b >= Tier3BackEdgeThreshold * scale;
77 case CompLevel_full_profile:
78 return b >= Tier4BackEdgeThreshold * scale;
79 }
80 return true;
81 }
82
83 // Simple methods are as good being compiled with C1 as C2.
84 // Determine if a given method is such a case.
85 bool TieredThresholdPolicy::is_trivial(Method* method) {
86 if (method->is_accessor() ||
87 method->is_constant_getter()) {
88 return true;
89 }
90 #if INCLUDE_JVMCI
91 if (UseJVMCICompiler) {
92 AbstractCompiler* comp = CompileBroker::compiler(CompLevel_full_optimization);
93 if (TieredCompilation && comp != NULL && comp->is_trivial(method)) {
94 return true;
95 }
96 }
97 #endif
98 if (method->has_loops() || method->code_size() >= 15) {
99 return false;
100 }
101 MethodData* mdo = method->method_data();
102 if (mdo != NULL && !mdo->would_profile() &&
103 (method->code_size() < 5 || (mdo->num_blocks() < 4))) {
104 return true;
105 }
106 return false;
107 }
108
109 inline CompLevel TieredThresholdPolicy::comp_level(Method* method) {
110 CompiledMethod *nm = method->code();
111 if (nm != NULL && nm->is_in_use()) {
112 return (CompLevel)nm->comp_level();
113 }
114 return CompLevel_none;
115 }
116
117 void TieredThresholdPolicy::print_counters(const char* prefix, const methodHandle& mh) {
118 int invocation_count = mh->invocation_count();
119 int backedge_count = mh->backedge_count();
120 MethodData* mdh = mh->method_data();
121 int mdo_invocations = 0, mdo_backedges = 0;
122 int mdo_invocations_start = 0, mdo_backedges_start = 0;
123 if (mdh != NULL) {
124 mdo_invocations = mdh->invocation_count();
125 mdo_backedges = mdh->backedge_count();
126 mdo_invocations_start = mdh->invocation_count_start();
127 mdo_backedges_start = mdh->backedge_count_start();
128 }
129 tty->print(" %stotal=%d,%d %smdo=%d(%d),%d(%d)", prefix,
130 invocation_count, backedge_count, prefix,
131 mdo_invocations, mdo_invocations_start,
132 mdo_backedges, mdo_backedges_start);
133 tty->print(" %smax levels=%d,%d", prefix,
134 mh->highest_comp_level(), mh->highest_osr_comp_level());
135 }
136
137 // Print an event.
138 void TieredThresholdPolicy::print_event(EventType type, const methodHandle& mh, const methodHandle& imh,
139 int bci, CompLevel level) {
140 bool inlinee_event = mh() != imh();
141
142 ttyLocker tty_lock;
143 tty->print("%lf: [", os::elapsedTime());
144
145 switch(type) {
146 case CALL:
147 tty->print("call");
148 break;
149 case LOOP:
150 tty->print("loop");
151 break;
152 case COMPILE:
153 tty->print("compile");
154 break;
155 case REMOVE_FROM_QUEUE:
156 tty->print("remove-from-queue");
157 break;
158 case UPDATE_IN_QUEUE:
159 tty->print("update-in-queue");
160 break;
161 case REPROFILE:
162 tty->print("reprofile");
163 break;
164 case MAKE_NOT_ENTRANT:
165 tty->print("make-not-entrant");
166 break;
167 default:
168 tty->print("unknown");
169 }
170
171 tty->print(" level=%d ", level);
172
173 ResourceMark rm;
174 char *method_name = mh->name_and_sig_as_C_string();
175 tty->print("[%s", method_name);
176 if (inlinee_event) {
177 char *inlinee_name = imh->name_and_sig_as_C_string();
178 tty->print(" [%s]] ", inlinee_name);
179 }
180 else tty->print("] ");
181 tty->print("@%d queues=%d,%d", bci, CompileBroker::queue_size(CompLevel_full_profile),
182 CompileBroker::queue_size(CompLevel_full_optimization));
183
184 print_specific(type, mh, imh, bci, level);
185
186 if (type != COMPILE) {
187 print_counters("", mh);
188 if (inlinee_event) {
189 print_counters("inlinee ", imh);
190 }
191 tty->print(" compilable=");
192 bool need_comma = false;
193 if (!mh->is_not_compilable(CompLevel_full_profile)) {
194 tty->print("c1");
195 need_comma = true;
196 }
197 if (!mh->is_not_osr_compilable(CompLevel_full_profile)) {
198 if (need_comma) tty->print(",");
199 tty->print("c1-osr");
200 need_comma = true;
201 }
202 if (!mh->is_not_compilable(CompLevel_full_optimization)) {
203 if (need_comma) tty->print(",");
204 tty->print("c2");
205 need_comma = true;
206 }
207 if (!mh->is_not_osr_compilable(CompLevel_full_optimization)) {
208 if (need_comma) tty->print(",");
209 tty->print("c2-osr");
210 }
211 tty->print(" status=");
212 if (mh->queued_for_compilation()) {
213 tty->print("in-queue");
214 } else tty->print("idle");
215 }
216 tty->print_cr("]");
217 }
218
219 void TieredThresholdPolicy::initialize() {
220 int count = CICompilerCount;
221 bool c1_only = TieredStopAtLevel < CompLevel_full_optimization;
222 #ifdef _LP64
223 // Turn on ergonomic compiler count selection
224 if (FLAG_IS_DEFAULT(CICompilerCountPerCPU) && FLAG_IS_DEFAULT(CICompilerCount)) {
225 FLAG_SET_DEFAULT(CICompilerCountPerCPU, true);
226 }
227 if (CICompilerCountPerCPU) {
228 // Simple log n seems to grow too slowly for tiered, try something faster: log n * log log n
229 int log_cpu = log2_int(os::active_processor_count());
230 int loglog_cpu = log2_int(MAX2(log_cpu, 1));
231 count = MAX2(log_cpu * loglog_cpu * 3 / 2, 2);
232 // Make sure there is enough space in the code cache to hold all the compiler buffers
233 size_t c1_size = Compiler::code_buffer_size();
234 size_t c2_size = C2Compiler::initial_code_buffer_size();
235 size_t buffer_size = c1_only ? c1_size : (c1_size/3 + 2*c2_size/3);
236 int max_count = (ReservedCodeCacheSize - (CodeCacheMinimumUseSpace DEBUG_ONLY(* 3))) / (int)buffer_size;
237 if (count > max_count) {
238 // Lower the compiler count such that all buffers fit into the code cache
239 count = MAX2(max_count, c1_only ? 1 : 2);
240 }
241 FLAG_SET_ERGO(intx, CICompilerCount, count);
242 }
243 #else
244 // On 32-bit systems, the number of compiler threads is limited to 3.
245 // On these systems, the virtual address space available to the JVM
246 // is usually limited to 2-4 GB (the exact value depends on the platform).
247 // As the compilers (especially C2) can consume a large amount of
248 // memory, scaling the number of compiler threads with the number of
249 // available cores can result in the exhaustion of the address space
250 /// available to the VM and thus cause the VM to crash.
251 if (FLAG_IS_DEFAULT(CICompilerCount)) {
252 count = 3;
253 FLAG_SET_ERGO(intx, CICompilerCount, count);
254 }
255 #endif
256
257 if (c1_only) {
258 // No C2 compiler thread required
259 set_c1_count(count);
260 } else {
261 set_c1_count(MAX2(count / 3, 1));
262 set_c2_count(MAX2(count - c1_count(), 1));
263 }
264 assert(count == c1_count() + c2_count(), "inconsistent compiler thread count");
265
266 // Some inlining tuning
267 #ifdef X86
268 if (FLAG_IS_DEFAULT(InlineSmallCode)) {
269 FLAG_SET_DEFAULT(InlineSmallCode, 2000);
270 }
271 #endif
272
273 #if defined SPARC || defined AARCH64
274 if (FLAG_IS_DEFAULT(InlineSmallCode)) {
275 FLAG_SET_DEFAULT(InlineSmallCode, 2500);
276 }
277 #endif
278
279 set_increase_threshold_at_ratio();
280 set_start_time(os::javaTimeMillis());
281 }
282
283 void TieredThresholdPolicy::set_carry_if_necessary(InvocationCounter *counter) {
284 if (!counter->carry() && counter->count() > InvocationCounter::count_limit / 2) {
285 counter->set_carry_flag();
286 }
287 }
288
289 // Set carry flags on the counters if necessary
290 void TieredThresholdPolicy::handle_counter_overflow(Method* method) {
291 MethodCounters *mcs = method->method_counters();
292 if (mcs != NULL) {
293 set_carry_if_necessary(mcs->invocation_counter());
294 set_carry_if_necessary(mcs->backedge_counter());
295 }
296 MethodData* mdo = method->method_data();
297 if (mdo != NULL) {
298 set_carry_if_necessary(mdo->invocation_counter());
299 set_carry_if_necessary(mdo->backedge_counter());
300 }
301 }
302
303 // Called with the queue locked and with at least one element
304 CompileTask* TieredThresholdPolicy::select_task(CompileQueue* compile_queue) {
305 CompileTask *max_blocking_task = NULL;
306 CompileTask *max_task = NULL;
307 Method* max_method = NULL;
308 jlong t = os::javaTimeMillis();
309 // Iterate through the queue and find a method with a maximum rate.
310 for (CompileTask* task = compile_queue->first(); task != NULL;) {
311 CompileTask* next_task = task->next();
312 Method* method = task->method();
313 update_rate(t, method);
314 if (max_task == NULL) {
315 max_task = task;
316 max_method = method;
317 } else {
318 // If a method has been stale for some time, remove it from the queue.
319 // Blocking tasks and tasks submitted from whitebox API don't become stale
320 if (task->can_become_stale() && is_stale(t, TieredCompileTaskTimeout, method) && !is_old(method)) {
321 if (PrintTieredEvents) {
322 print_event(REMOVE_FROM_QUEUE, method, method, task->osr_bci(), (CompLevel)task->comp_level());
323 }
324 compile_queue->remove_and_mark_stale(task);
325 method->clear_queued_for_compilation();
326 task = next_task;
327 continue;
328 }
329
330 // Select a method with a higher rate
331 if (compare_methods(method, max_method)) {
332 max_task = task;
333 max_method = method;
334 }
335 }
336
337 if (task->is_blocking()) {
338 if (max_blocking_task == NULL || compare_methods(method, max_blocking_task->method())) {
339 max_blocking_task = task;
340 }
341 }
342
343 task = next_task;
344 }
345
346 if (max_blocking_task != NULL) {
347 // In blocking compilation mode, the CompileBroker will make
348 // compilations submitted by a JVMCI compiler thread non-blocking. These
349 // compilations should be scheduled after all blocking compilations
350 // to service non-compiler related compilations sooner and reduce the
351 // chance of such compilations timing out.
352 max_task = max_blocking_task;
353 max_method = max_task->method();
354 }
355
356 if (max_task != NULL && max_task->comp_level() == CompLevel_full_profile &&
357 TieredStopAtLevel > CompLevel_full_profile &&
358 max_method != NULL && is_method_profiled(max_method)) {
359 max_task->set_comp_level(CompLevel_limited_profile);
360
361 if (CompileBroker::compilation_is_complete(max_method, max_task->osr_bci(), CompLevel_limited_profile)) {
362 if (PrintTieredEvents) {
363 print_event(REMOVE_FROM_QUEUE, max_method, max_method, max_task->osr_bci(), (CompLevel)max_task->comp_level());
364 }
365 compile_queue->remove_and_mark_stale(max_task);
366 max_method->clear_queued_for_compilation();
367 return NULL;
368 }
369
370 if (PrintTieredEvents) {
371 print_event(UPDATE_IN_QUEUE, max_method, max_method, max_task->osr_bci(), (CompLevel)max_task->comp_level());
372 }
373 }
374
375 return max_task;
376 }
377
378 void TieredThresholdPolicy::reprofile(ScopeDesc* trap_scope, bool is_osr) {
379 for (ScopeDesc* sd = trap_scope;; sd = sd->sender()) {
380 if (PrintTieredEvents) {
381 methodHandle mh(sd->method());
382 print_event(REPROFILE, mh, mh, InvocationEntryBci, CompLevel_none);
383 }
384 MethodData* mdo = sd->method()->method_data();
385 if (mdo != NULL) {
386 mdo->reset_start_counters();
387 }
388 if (sd->is_top()) break;
389 }
390 }
391
392 nmethod* TieredThresholdPolicy::event(const methodHandle& method, const methodHandle& inlinee,
393 int branch_bci, int bci, CompLevel comp_level, CompiledMethod* nm, JavaThread* thread) {
394 if (comp_level == CompLevel_none &&
395 JvmtiExport::can_post_interpreter_events() &&
396 thread->is_interp_only_mode()) {
397 return NULL;
398 }
399 if (CompileTheWorld || ReplayCompiles) {
400 // Don't trigger other compiles in testing mode
401 return NULL;
402 }
403
404 handle_counter_overflow(method());
405 if (method() != inlinee()) {
406 handle_counter_overflow(inlinee());
407 }
408
409 if (PrintTieredEvents) {
410 print_event(bci == InvocationEntryBci ? CALL : LOOP, method, inlinee, bci, comp_level);
411 }
412
413 if (bci == InvocationEntryBci) {
414 method_invocation_event(method, inlinee, comp_level, nm, thread);
415 } else {
416 // method == inlinee if the event originated in the main method
417 method_back_branch_event(method, inlinee, bci, comp_level, nm, thread);
418 // Check if event led to a higher level OSR compilation
419 nmethod* osr_nm = inlinee->lookup_osr_nmethod_for(bci, comp_level, false);
420 if (osr_nm != NULL && osr_nm->comp_level() > comp_level) {
421 // Perform OSR with new nmethod
422 return osr_nm;
423 }
424 }
425 return NULL;
426 }
427
428 // Check if the method can be compiled, change level if necessary
429 void TieredThresholdPolicy::compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) {
430 assert(level <= TieredStopAtLevel, "Invalid compilation level");
431 if (level == CompLevel_none) {
432 return;
433 }
434 if (level == CompLevel_aot) {
435 if (mh->has_aot_code()) {
436 if (PrintTieredEvents) {
437 print_event(COMPILE, mh, mh, bci, level);
438 }
439 MutexLocker ml(Compile_lock);
440 NoSafepointVerifier nsv;
441 if (mh->has_aot_code() && mh->code() != mh->aot_code()) {
442 mh->aot_code()->make_entrant();
443 if (mh->has_compiled_code()) {
444 mh->code()->make_not_entrant();
445 }
446 Method::set_code(mh, mh->aot_code());
447 }
448 }
449 return;
450 }
451
452 // Check if the method can be compiled. If it cannot be compiled with C1, continue profiling
453 // in the interpreter and then compile with C2 (the transition function will request that,
454 // see common() ). If the method cannot be compiled with C2 but still can with C1, compile it with
455 // pure C1.
456 if (!can_be_compiled(mh, level)) {
457 if (level == CompLevel_full_optimization && can_be_compiled(mh, CompLevel_simple)) {
458 compile(mh, bci, CompLevel_simple, thread);
459 }
460 return;
461 }
462 if (bci != InvocationEntryBci && mh->is_not_osr_compilable(level)) {
463 return;
464 }
465 if (!CompileBroker::compilation_is_in_queue(mh)) {
466 if (PrintTieredEvents) {
467 print_event(COMPILE, mh, mh, bci, level);
468 }
469 submit_compile(mh, bci, level, thread);
470 }
471 }
472
473 // Update the rate and submit compile
474 void TieredThresholdPolicy::submit_compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) {
475 int hot_count = (bci == InvocationEntryBci) ? mh->invocation_count() : mh->backedge_count();
476 update_rate(os::javaTimeMillis(), mh());
477 CompileBroker::compile_method(mh, bci, level, mh, hot_count, CompileTask::Reason_Tiered, thread);
478 }
479
480 // Print an event.
481 void TieredThresholdPolicy::print_specific(EventType type, const methodHandle& mh, const methodHandle& imh,
482 int bci, CompLevel level) {
483 tty->print(" rate=");
484 if (mh->prev_time() == 0) tty->print("n/a");
485 else tty->print("%f", mh->rate());
486
487 tty->print(" k=%.2lf,%.2lf", threshold_scale(CompLevel_full_profile, Tier3LoadFeedback),
488 threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback));
489
490 }
491
492 // update_rate() is called from select_task() while holding a compile queue lock.
493 void TieredThresholdPolicy::update_rate(jlong t, Method* m) {
494 // Skip update if counters are absent.
495 // Can't allocate them since we are holding compile queue lock.
496 if (m->method_counters() == NULL) return;
497
498 if (is_old(m)) {
499 // We don't remove old methods from the queue,
500 // so we can just zero the rate.
501 m->set_rate(0);
502 return;
503 }
504
505 // We don't update the rate if we've just came out of a safepoint.
506 // delta_s is the time since last safepoint in milliseconds.
507 jlong delta_s = t - SafepointSynchronize::end_of_last_safepoint();
508 jlong delta_t = t - (m->prev_time() != 0 ? m->prev_time() : start_time()); // milliseconds since the last measurement
509 // How many events were there since the last time?
510 int event_count = m->invocation_count() + m->backedge_count();
511 int delta_e = event_count - m->prev_event_count();
512
513 // We should be running for at least 1ms.
514 if (delta_s >= TieredRateUpdateMinTime) {
515 // And we must've taken the previous point at least 1ms before.
516 if (delta_t >= TieredRateUpdateMinTime && delta_e > 0) {
517 m->set_prev_time(t);
518 m->set_prev_event_count(event_count);
519 m->set_rate((float)delta_e / (float)delta_t); // Rate is events per millisecond
520 } else {
521 if (delta_t > TieredRateUpdateMaxTime && delta_e == 0) {
522 // If nothing happened for 25ms, zero the rate. Don't modify prev values.
523 m->set_rate(0);
524 }
525 }
526 }
527 }
528
529 // Check if this method has been stale from a given number of milliseconds.
530 // See select_task().
531 bool TieredThresholdPolicy::is_stale(jlong t, jlong timeout, Method* m) {
532 jlong delta_s = t - SafepointSynchronize::end_of_last_safepoint();
533 jlong delta_t = t - m->prev_time();
534 if (delta_t > timeout && delta_s > timeout) {
535 int event_count = m->invocation_count() + m->backedge_count();
536 int delta_e = event_count - m->prev_event_count();
537 // Return true if there were no events.
538 return delta_e == 0;
539 }
540 return false;
541 }
542
543 // We don't remove old methods from the compile queue even if they have
544 // very low activity. See select_task().
545 bool TieredThresholdPolicy::is_old(Method* method) {
546 return method->invocation_count() > 50000 || method->backedge_count() > 500000;
547 }
548
549 double TieredThresholdPolicy::weight(Method* method) {
550 return (double)(method->rate() + 1) *
551 (method->invocation_count() + 1) * (method->backedge_count() + 1);
552 }
553
554 // Apply heuristics and return true if x should be compiled before y
555 bool TieredThresholdPolicy::compare_methods(Method* x, Method* y) {
556 if (x->highest_comp_level() > y->highest_comp_level()) {
557 // recompilation after deopt
558 return true;
559 } else
560 if (x->highest_comp_level() == y->highest_comp_level()) {
561 if (weight(x) > weight(y)) {
562 return true;
563 }
564 }
565 return false;
566 }
567
568 // Is method profiled enough?
569 bool TieredThresholdPolicy::is_method_profiled(Method* method) {
570 MethodData* mdo = method->method_data();
571 if (mdo != NULL) {
572 int i = mdo->invocation_count_delta();
573 int b = mdo->backedge_count_delta();
574 return call_predicate_helper<CompLevel_full_profile>(i, b, 1, method);
575 }
576 return false;
577 }
578
579 double TieredThresholdPolicy::threshold_scale(CompLevel level, int feedback_k) {
580 double queue_size = CompileBroker::queue_size(level);
581 int comp_count = compiler_count(level);
582 double k = queue_size / (feedback_k * comp_count) + 1;
583
584 // Increase C1 compile threshold when the code cache is filled more
585 // than specified by IncreaseFirstTierCompileThresholdAt percentage.
586 // The main intention is to keep enough free space for C2 compiled code
587 // to achieve peak performance if the code cache is under stress.
588 if ((TieredStopAtLevel == CompLevel_full_optimization) && (level != CompLevel_full_optimization)) {
589 double current_reverse_free_ratio = CodeCache::reverse_free_ratio(CodeCache::get_code_blob_type(level));
590 if (current_reverse_free_ratio > _increase_threshold_at_ratio) {
591 k *= exp(current_reverse_free_ratio - _increase_threshold_at_ratio);
592 }
593 }
594 return k;
595 }
596
597 // Call and loop predicates determine whether a transition to a higher
598 // compilation level should be performed (pointers to predicate functions
599 // are passed to common()).
600 // Tier?LoadFeedback is basically a coefficient that determines of
601 // how many methods per compiler thread can be in the queue before
602 // the threshold values double.
603 bool TieredThresholdPolicy::loop_predicate(int i, int b, CompLevel cur_level, Method* method) {
604 switch(cur_level) {
605 case CompLevel_aot: {
606 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
607 return loop_predicate_helper<CompLevel_aot>(i, b, k, method);
608 }
609 case CompLevel_none:
610 case CompLevel_limited_profile: {
611 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
612 return loop_predicate_helper<CompLevel_none>(i, b, k, method);
613 }
614 case CompLevel_full_profile: {
615 double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);
616 return loop_predicate_helper<CompLevel_full_profile>(i, b, k, method);
617 }
618 default:
619 return true;
620 }
621 }
622
623 bool TieredThresholdPolicy::call_predicate(int i, int b, CompLevel cur_level, Method* method) {
624 switch(cur_level) {
625 case CompLevel_aot: {
626 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
627 return call_predicate_helper<CompLevel_aot>(i, b, k, method);
628 }
629 case CompLevel_none:
630 case CompLevel_limited_profile: {
631 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
632 return call_predicate_helper<CompLevel_none>(i, b, k, method);
633 }
634 case CompLevel_full_profile: {
635 double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);
636 return call_predicate_helper<CompLevel_full_profile>(i, b, k, method);
637 }
638 default:
639 return true;
640 }
641 }
642
643 // Determine is a method is mature.
644 bool TieredThresholdPolicy::is_mature(Method* method) {
645 if (is_trivial(method)) return true;
646 MethodData* mdo = method->method_data();
647 if (mdo != NULL) {
648 int i = mdo->invocation_count();
649 int b = mdo->backedge_count();
650 double k = ProfileMaturityPercentage / 100.0;
651 return call_predicate_helper<CompLevel_full_profile>(i, b, k, method) ||
652 loop_predicate_helper<CompLevel_full_profile>(i, b, k, method);
653 }
654 return false;
655 }
656
657 // If a method is old enough and is still in the interpreter we would want to
658 // start profiling without waiting for the compiled method to arrive.
659 // We also take the load on compilers into the account.
660 bool TieredThresholdPolicy::should_create_mdo(Method* method, CompLevel cur_level) {
661 if (cur_level == CompLevel_none &&
662 CompileBroker::queue_size(CompLevel_full_optimization) <=
663 Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {
664 int i = method->invocation_count();
665 int b = method->backedge_count();
666 double k = Tier0ProfilingStartPercentage / 100.0;
667 return call_predicate_helper<CompLevel_none>(i, b, k, method) || loop_predicate_helper<CompLevel_none>(i, b, k, method);
668 }
669 return false;
670 }
671
672 // Inlining control: if we're compiling a profiled method with C1 and the callee
673 // is known to have OSRed in a C2 version, don't inline it.
674 bool TieredThresholdPolicy::should_not_inline(ciEnv* env, ciMethod* callee) {
675 CompLevel comp_level = (CompLevel)env->comp_level();
676 if (comp_level == CompLevel_full_profile ||
677 comp_level == CompLevel_limited_profile) {
678 return callee->highest_osr_comp_level() == CompLevel_full_optimization;
679 }
680 return false;
681 }
682
683 // Create MDO if necessary.
684 void TieredThresholdPolicy::create_mdo(const methodHandle& mh, JavaThread* THREAD) {
685 if (mh->is_native() ||
686 mh->is_abstract() ||
687 mh->is_accessor() ||
688 mh->is_constant_getter()) {
689 return;
690 }
691 if (mh->method_data() == NULL) {
692 Method::build_interpreter_method_data(mh, CHECK_AND_CLEAR);
693 }
694 }
695
696
697 /*
698 * Method states:
699 * 0 - interpreter (CompLevel_none)
700 * 1 - pure C1 (CompLevel_simple)
701 * 2 - C1 with invocation and backedge counting (CompLevel_limited_profile)
702 * 3 - C1 with full profiling (CompLevel_full_profile)
703 * 4 - C2 (CompLevel_full_optimization)
704 *
705 * Common state transition patterns:
706 * a. 0 -> 3 -> 4.
707 * The most common path. But note that even in this straightforward case
708 * profiling can start at level 0 and finish at level 3.
709 *
710 * b. 0 -> 2 -> 3 -> 4.
711 * This case occurs when the load on C2 is deemed too high. So, instead of transitioning
712 * into state 3 directly and over-profiling while a method is in the C2 queue we transition to
713 * level 2 and wait until the load on C2 decreases. This path is disabled for OSRs.
714 *
715 * c. 0 -> (3->2) -> 4.
716 * In this case we enqueue a method for compilation at level 3, but the C1 queue is long enough
717 * to enable the profiling to fully occur at level 0. In this case we change the compilation level
718 * of the method to 2 while the request is still in-queue, because it'll allow it to run much faster
719 * without full profiling while c2 is compiling.
720 *
721 * d. 0 -> 3 -> 1 or 0 -> 2 -> 1.
722 * After a method was once compiled with C1 it can be identified as trivial and be compiled to
723 * level 1. These transition can also occur if a method can't be compiled with C2 but can with C1.
724 *
725 * e. 0 -> 4.
726 * This can happen if a method fails C1 compilation (it will still be profiled in the interpreter)
727 * or because of a deopt that didn't require reprofiling (compilation won't happen in this case because
728 * the compiled version already exists).
729 *
730 * Note that since state 0 can be reached from any other state via deoptimization different loops
731 * are possible.
732 *
733 */
734
735 // Common transition function. Given a predicate determines if a method should transition to another level.
736 CompLevel TieredThresholdPolicy::common(Predicate p, Method* method, CompLevel cur_level, bool disable_feedback) {
737 CompLevel next_level = cur_level;
738 int i = method->invocation_count();
739 int b = method->backedge_count();
740
741 if (is_trivial(method)) {
742 next_level = CompLevel_simple;
743 } else {
744 switch(cur_level) {
745 default: break;
746 case CompLevel_aot: {
747 // If we were at full profile level, would we switch to full opt?
748 if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) {
749 next_level = CompLevel_full_optimization;
750 } else if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
751 Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
752 (this->*p)(i, b, cur_level, method))) {
753 next_level = CompLevel_full_profile;
754 }
755 }
756 break;
757 case CompLevel_none:
758 // If we were at full profile level, would we switch to full opt?
759 if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) {
760 next_level = CompLevel_full_optimization;
761 } else if ((this->*p)(i, b, cur_level, method)) {
762 #if INCLUDE_JVMCI
763 if (EnableJVMCI && UseJVMCICompiler) {
764 // Since JVMCI takes a while to warm up, its queue inevitably backs up during
765 // early VM execution. As of 2014-06-13, JVMCI's inliner assumes that the root
766 // compilation method and all potential inlinees have mature profiles (which
767 // includes type profiling). If it sees immature profiles, JVMCI's inliner
768 // can perform pathologically bad (e.g., causing OutOfMemoryErrors due to
769 // exploring/inlining too many graphs). Since a rewrite of the inliner is
770 // in progress, we simply disable the dialing back heuristic for now and will
771 // revisit this decision once the new inliner is completed.
772 next_level = CompLevel_full_profile;
773 } else
774 #endif
775 {
776 // C1-generated fully profiled code is about 30% slower than the limited profile
777 // code that has only invocation and backedge counters. The observation is that
778 // if C2 queue is large enough we can spend too much time in the fully profiled code
779 // while waiting for C2 to pick the method from the queue. To alleviate this problem
780 // we introduce a feedback on the C2 queue size. If the C2 queue is sufficiently long
781 // we choose to compile a limited profiled version and then recompile with full profiling
782 // when the load on C2 goes down.
783 if (!disable_feedback && CompileBroker::queue_size(CompLevel_full_optimization) >
784 Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {
785 next_level = CompLevel_limited_profile;
786 } else {
787 next_level = CompLevel_full_profile;
788 }
789 }
790 }
791 break;
792 case CompLevel_limited_profile:
793 if (is_method_profiled(method)) {
794 // Special case: we got here because this method was fully profiled in the interpreter.
795 next_level = CompLevel_full_optimization;
796 } else {
797 MethodData* mdo = method->method_data();
798 if (mdo != NULL) {
799 if (mdo->would_profile()) {
800 if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
801 Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
802 (this->*p)(i, b, cur_level, method))) {
803 next_level = CompLevel_full_profile;
804 }
805 } else {
806 next_level = CompLevel_full_optimization;
807 }
808 } else {
809 // If there is no MDO we need to profile
810 if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
811 Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
812 (this->*p)(i, b, cur_level, method))) {
813 next_level = CompLevel_full_profile;
814 }
815 }
816 }
817 break;
818 case CompLevel_full_profile:
819 {
820 MethodData* mdo = method->method_data();
821 if (mdo != NULL) {
822 if (mdo->would_profile()) {
823 int mdo_i = mdo->invocation_count_delta();
824 int mdo_b = mdo->backedge_count_delta();
825 if ((this->*p)(mdo_i, mdo_b, cur_level, method)) {
826 next_level = CompLevel_full_optimization;
827 }
828 } else {
829 next_level = CompLevel_full_optimization;
830 }
831 }
832 }
833 break;
834 }
835 }
836 return MIN2(next_level, (CompLevel)TieredStopAtLevel);
837 }
838
839 // Determine if a method should be compiled with a normal entry point at a different level.
840 CompLevel TieredThresholdPolicy::call_event(Method* method, CompLevel cur_level, JavaThread * thread) {
841 CompLevel osr_level = MIN2((CompLevel) method->highest_osr_comp_level(),
842 common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true));
843 CompLevel next_level = common(&TieredThresholdPolicy::call_predicate, method, cur_level);
844
845 // If OSR method level is greater than the regular method level, the levels should be
846 // equalized by raising the regular method level in order to avoid OSRs during each
847 // invocation of the method.
848 if (osr_level == CompLevel_full_optimization && cur_level == CompLevel_full_profile) {
849 MethodData* mdo = method->method_data();
850 guarantee(mdo != NULL, "MDO should not be NULL");
851 if (mdo->invocation_count() >= 1) {
852 next_level = CompLevel_full_optimization;
853 }
854 } else {
855 next_level = MAX2(osr_level, next_level);
856 }
857 #if INCLUDE_JVMCI
858 if (UseJVMCICompiler) {
859 next_level = JVMCIRuntime::adjust_comp_level(method, false, next_level, thread);
860 }
861 #endif
862 return next_level;
863 }
864
865 // Determine if we should do an OSR compilation of a given method.
866 CompLevel TieredThresholdPolicy::loop_event(Method* method, CompLevel cur_level, JavaThread* thread) {
867 CompLevel next_level = common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true);
868 if (cur_level == CompLevel_none) {
869 // If there is a live OSR method that means that we deopted to the interpreter
870 // for the transition.
871 CompLevel osr_level = MIN2((CompLevel)method->highest_osr_comp_level(), next_level);
872 if (osr_level > CompLevel_none) {
873 return osr_level;
874 }
875 }
876 #if INCLUDE_JVMCI
877 if (UseJVMCICompiler) {
878 next_level = JVMCIRuntime::adjust_comp_level(method, true, next_level, thread);
879 }
880 #endif
881 return next_level;
882 }
883
884 bool TieredThresholdPolicy::maybe_switch_to_aot(const methodHandle& mh, CompLevel cur_level, CompLevel next_level, JavaThread* thread) {
885 if (UseAOT && !delay_compilation_during_startup()) {
886 if (cur_level == CompLevel_full_profile || cur_level == CompLevel_none) {
887 // If the current level is full profile or interpreter and we're switching to any other level,
888 // activate the AOT code back first so that we won't waste time overprofiling.
889 compile(mh, InvocationEntryBci, CompLevel_aot, thread);
890 // Fall through for JIT compilation.
891 }
892 if (next_level == CompLevel_limited_profile && cur_level != CompLevel_aot && mh->has_aot_code()) {
893 // If the next level is limited profile, use the aot code (if there is any),
894 // since it's essentially the same thing.
895 compile(mh, InvocationEntryBci, CompLevel_aot, thread);
896 // Not need to JIT, we're done.
897 return true;
898 }
899 }
900 return false;
901 }
902
903
904 // Handle the invocation event.
905 void TieredThresholdPolicy::method_invocation_event(const methodHandle& mh, const methodHandle& imh,
906 CompLevel level, CompiledMethod* nm, JavaThread* thread) {
907 if (should_create_mdo(mh(), level)) {
908 create_mdo(mh, thread);
909 }
910 CompLevel next_level = call_event(mh(), level, thread);
911 if (next_level != level) {
912 if (maybe_switch_to_aot(mh, level, next_level, thread)) {
913 // No JITting necessary
914 return;
915 }
916 if (is_compilation_enabled() && !CompileBroker::compilation_is_in_queue(mh)) {
917 compile(mh, InvocationEntryBci, next_level, thread);
918 }
919 }
920 }
921
922 // Handle the back branch event. Notice that we can compile the method
923 // with a regular entry from here.
924 void TieredThresholdPolicy::method_back_branch_event(const methodHandle& mh, const methodHandle& imh,
925 int bci, CompLevel level, CompiledMethod* nm, JavaThread* thread) {
926 if (should_create_mdo(mh(), level)) {
927 create_mdo(mh, thread);
928 }
929 // Check if MDO should be created for the inlined method
930 if (should_create_mdo(imh(), level)) {
931 create_mdo(imh, thread);
932 }
933
934 if (is_compilation_enabled()) {
935 CompLevel next_osr_level = loop_event(imh(), level, thread);
936 CompLevel max_osr_level = (CompLevel)imh->highest_osr_comp_level();
937 // At the very least compile the OSR version
938 if (!CompileBroker::compilation_is_in_queue(imh) && (next_osr_level != level)) {
939 compile(imh, bci, next_osr_level, thread);
940 }
941
942 // Use loop event as an opportunity to also check if there's been
943 // enough calls.
944 CompLevel cur_level, next_level;
945 if (mh() != imh()) { // If there is an enclosing method
946 if (level == CompLevel_aot) {
947 // Recompile the enclosing method to prevent infinite OSRs. Stay at AOT level while it's compiling.
948 if (max_osr_level != CompLevel_none && !CompileBroker::compilation_is_in_queue(mh)) {
949 compile(mh, InvocationEntryBci, MIN2((CompLevel)TieredStopAtLevel, CompLevel_full_profile), thread);
950 }
951 } else {
952 // Current loop event level is not AOT
953 guarantee(nm != NULL, "Should have nmethod here");
954 cur_level = comp_level(mh());
955 next_level = call_event(mh(), cur_level, thread);
956
957 if (max_osr_level == CompLevel_full_optimization) {
958 // The inlinee OSRed to full opt, we need to modify the enclosing method to avoid deopts
959 bool make_not_entrant = false;
960 if (nm->is_osr_method()) {
961 // This is an osr method, just make it not entrant and recompile later if needed
962 make_not_entrant = true;
963 } else {
964 if (next_level != CompLevel_full_optimization) {
965 // next_level is not full opt, so we need to recompile the
966 // enclosing method without the inlinee
967 cur_level = CompLevel_none;
968 make_not_entrant = true;
969 }
970 }
971 if (make_not_entrant) {
972 if (PrintTieredEvents) {
973 int osr_bci = nm->is_osr_method() ? nm->osr_entry_bci() : InvocationEntryBci;
974 print_event(MAKE_NOT_ENTRANT, mh(), mh(), osr_bci, level);
975 }
976 nm->make_not_entrant();
977 }
978 }
979 // Fix up next_level if necessary to avoid deopts
980 if (next_level == CompLevel_limited_profile && max_osr_level == CompLevel_full_profile) {
981 next_level = CompLevel_full_profile;
982 }
983 if (cur_level != next_level) {
984 if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) {
985 compile(mh, InvocationEntryBci, next_level, thread);
986 }
987 }
988 }
989 } else {
990 cur_level = comp_level(mh());
991 next_level = call_event(mh(), cur_level, thread);
992 if (next_level != cur_level) {
993 if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) {
994 compile(mh, InvocationEntryBci, next_level, thread);
995 }
996 }
997 }
998 }
999 }
1000
1001 #endif