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 bool TieredThresholdPolicy::should_compile_at_level_simple(Method* method) {
95 if (TieredThresholdPolicy::is_trivial(method)) {
96 return true;
97 }
98 #if INCLUDE_JVMCI
99 if (UseJVMCICompiler) {
100 AbstractCompiler* comp = CompileBroker::compiler(CompLevel_full_optimization);
101 if (comp != NULL && comp->is_jvmci() && ((JVMCICompiler*) comp)->force_comp_at_level_simple(method)) {
102 return true;
103 }
104 }
105 #endif
106 return false;
107 }
108
109 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(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(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 // If a method was unloaded or has been stale for some time, remove it from the queue.
314 // Blocking tasks and tasks submitted from whitebox API don't become stale
315 if (task->is_unloaded() || (task->can_become_stale() && is_stale(t, TieredCompileTaskTimeout, method) && !is_old(method))) {
316 if (!task->is_unloaded()) {
317 if (PrintTieredEvents) {
318 print_event(REMOVE_FROM_QUEUE, method, method, task->osr_bci(), (CompLevel) task->comp_level());
319 }
320 method->clear_queued_for_compilation();
321 }
322 compile_queue->remove_and_mark_stale(task);
323 task = next_task;
324 continue;
325 }
326 update_rate(t, method);
327 if (max_task == NULL || compare_methods(method, max_method)) {
328 // Select a method with the highest rate
329 max_task = task;
330 max_method = method;
331 }
332
333 if (task->is_blocking()) {
334 if (max_blocking_task == NULL || compare_methods(method, max_blocking_task->method())) {
335 max_blocking_task = task;
336 }
337 }
338
339 task = next_task;
340 }
341
342 if (max_blocking_task != NULL) {
343 // In blocking compilation mode, the CompileBroker will make
344 // compilations submitted by a JVMCI compiler thread non-blocking. These
345 // compilations should be scheduled after all blocking compilations
346 // to service non-compiler related compilations sooner and reduce the
347 // chance of such compilations timing out.
348 max_task = max_blocking_task;
349 max_method = max_task->method();
350 }
351
352 if (max_task != NULL && max_task->comp_level() == CompLevel_full_profile &&
353 TieredStopAtLevel > CompLevel_full_profile &&
354 max_method != NULL && is_method_profiled(max_method)) {
355 max_task->set_comp_level(CompLevel_limited_profile);
356
357 if (CompileBroker::compilation_is_complete(max_method, max_task->osr_bci(), CompLevel_limited_profile)) {
358 if (PrintTieredEvents) {
359 print_event(REMOVE_FROM_QUEUE, max_method, max_method, max_task->osr_bci(), (CompLevel)max_task->comp_level());
360 }
361 compile_queue->remove_and_mark_stale(max_task);
362 max_method->clear_queued_for_compilation();
363 return NULL;
364 }
365
366 if (PrintTieredEvents) {
367 print_event(UPDATE_IN_QUEUE, max_method, max_method, max_task->osr_bci(), (CompLevel)max_task->comp_level());
368 }
369 }
370
371 return max_task;
372 }
373
374 void TieredThresholdPolicy::reprofile(ScopeDesc* trap_scope, bool is_osr) {
375 for (ScopeDesc* sd = trap_scope;; sd = sd->sender()) {
376 if (PrintTieredEvents) {
377 methodHandle mh(sd->method());
378 print_event(REPROFILE, mh, mh, InvocationEntryBci, CompLevel_none);
379 }
380 MethodData* mdo = sd->method()->method_data();
381 if (mdo != NULL) {
382 mdo->reset_start_counters();
383 }
384 if (sd->is_top()) break;
385 }
386 }
387
388 nmethod* TieredThresholdPolicy::event(const methodHandle& method, const methodHandle& inlinee,
389 int branch_bci, int bci, CompLevel comp_level, CompiledMethod* nm, JavaThread* thread) {
390 if (comp_level == CompLevel_none &&
391 JvmtiExport::can_post_interpreter_events() &&
392 thread->is_interp_only_mode()) {
393 return NULL;
394 }
395 if (ReplayCompiles) {
396 // Don't trigger other compiles in testing mode
397 return NULL;
398 }
399
400 handle_counter_overflow(method());
401 if (method() != inlinee()) {
402 handle_counter_overflow(inlinee());
403 }
404
405 if (PrintTieredEvents) {
406 print_event(bci == InvocationEntryBci ? CALL : LOOP, method, inlinee, bci, comp_level);
407 }
408
409 if (bci == InvocationEntryBci) {
410 method_invocation_event(method, inlinee, comp_level, nm, thread);
411 } else {
412 // method == inlinee if the event originated in the main method
413 method_back_branch_event(method, inlinee, bci, comp_level, nm, thread);
414 // Check if event led to a higher level OSR compilation
415 nmethod* osr_nm = inlinee->lookup_osr_nmethod_for(bci, comp_level, false);
416 if (osr_nm != NULL && osr_nm->comp_level() > comp_level) {
417 // Perform OSR with new nmethod
418 return osr_nm;
419 }
420 }
421 return NULL;
422 }
423
424 // Check if the method can be compiled, change level if necessary
425 void TieredThresholdPolicy::compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) {
426 assert(level <= TieredStopAtLevel, "Invalid compilation level");
427 if (level == CompLevel_none) {
428 return;
429 }
430 if (level == CompLevel_aot) {
431 if (mh->has_aot_code()) {
432 if (PrintTieredEvents) {
433 print_event(COMPILE, mh, mh, bci, level);
434 }
435 MutexLocker ml(Compile_lock);
436 NoSafepointVerifier nsv;
437 if (mh->has_aot_code() && mh->code() != mh->aot_code()) {
438 mh->aot_code()->make_entrant();
439 if (mh->has_compiled_code()) {
440 mh->code()->make_not_entrant();
441 }
442 Method::set_code(mh, mh->aot_code());
443 }
444 }
445 return;
446 }
447
448 // Check if the method can be compiled. If it cannot be compiled with C1, continue profiling
449 // in the interpreter and then compile with C2 (the transition function will request that,
450 // see common() ). If the method cannot be compiled with C2 but still can with C1, compile it with
451 // pure C1.
452 if (!can_be_compiled(mh, level)) {
453 if (level == CompLevel_full_optimization && can_be_compiled(mh, CompLevel_simple)) {
454 compile(mh, bci, CompLevel_simple, thread);
455 }
456 return;
457 }
458 if (bci != InvocationEntryBci && mh->is_not_osr_compilable(level)) {
459 return;
460 }
461 if (!CompileBroker::compilation_is_in_queue(mh)) {
462 if (PrintTieredEvents) {
463 print_event(COMPILE, mh, mh, bci, level);
464 }
465 submit_compile(mh, bci, level, thread);
466 }
467 }
468
469 // Update the rate and submit compile
470 void TieredThresholdPolicy::submit_compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) {
471 int hot_count = (bci == InvocationEntryBci) ? mh->invocation_count() : mh->backedge_count();
472 update_rate(os::javaTimeMillis(), mh());
473 CompileBroker::compile_method(mh, bci, level, mh, hot_count, CompileTask::Reason_Tiered, thread);
474 }
475
476 // Print an event.
477 void TieredThresholdPolicy::print_specific(EventType type, const methodHandle& mh, const methodHandle& imh,
478 int bci, CompLevel level) {
479 tty->print(" rate=");
480 if (mh->prev_time() == 0) tty->print("n/a");
481 else tty->print("%f", mh->rate());
482
483 tty->print(" k=%.2lf,%.2lf", threshold_scale(CompLevel_full_profile, Tier3LoadFeedback),
484 threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback));
485
486 }
487
488 // update_rate() is called from select_task() while holding a compile queue lock.
489 void TieredThresholdPolicy::update_rate(jlong t, Method* m) {
490 // Skip update if counters are absent.
491 // Can't allocate them since we are holding compile queue lock.
492 if (m->method_counters() == NULL) return;
493
494 if (is_old(m)) {
495 // We don't remove old methods from the queue,
496 // so we can just zero the rate.
497 m->set_rate(0);
498 return;
499 }
500
501 // We don't update the rate if we've just came out of a safepoint.
502 // delta_s is the time since last safepoint in milliseconds.
503 jlong delta_s = t - SafepointTracing::end_of_last_safepoint_epoch_ms();
504 jlong delta_t = t - (m->prev_time() != 0 ? m->prev_time() : start_time()); // milliseconds since the last measurement
505 // How many events were there since the last time?
506 int event_count = m->invocation_count() + m->backedge_count();
507 int delta_e = event_count - m->prev_event_count();
508
509 // We should be running for at least 1ms.
510 if (delta_s >= TieredRateUpdateMinTime) {
511 // And we must've taken the previous point at least 1ms before.
512 if (delta_t >= TieredRateUpdateMinTime && delta_e > 0) {
513 m->set_prev_time(t);
514 m->set_prev_event_count(event_count);
515 m->set_rate((float)delta_e / (float)delta_t); // Rate is events per millisecond
516 } else {
517 if (delta_t > TieredRateUpdateMaxTime && delta_e == 0) {
518 // If nothing happened for 25ms, zero the rate. Don't modify prev values.
519 m->set_rate(0);
520 }
521 }
522 }
523 }
524
525 // Check if this method has been stale for a given number of milliseconds.
526 // See select_task().
527 bool TieredThresholdPolicy::is_stale(jlong t, jlong timeout, Method* m) {
528 jlong delta_s = t - SafepointTracing::end_of_last_safepoint_epoch_ms();
529 jlong delta_t = t - m->prev_time();
530 if (delta_t > timeout && delta_s > timeout) {
531 int event_count = m->invocation_count() + m->backedge_count();
532 int delta_e = event_count - m->prev_event_count();
533 // Return true if there were no events.
534 return delta_e == 0;
535 }
536 return false;
537 }
538
539 // We don't remove old methods from the compile queue even if they have
540 // very low activity. See select_task().
541 bool TieredThresholdPolicy::is_old(Method* method) {
542 return method->invocation_count() > 50000 || method->backedge_count() > 500000;
543 }
544
545 double TieredThresholdPolicy::weight(Method* method) {
546 return (double)(method->rate() + 1) *
547 (method->invocation_count() + 1) * (method->backedge_count() + 1);
548 }
549
550 // Apply heuristics and return true if x should be compiled before y
551 bool TieredThresholdPolicy::compare_methods(Method* x, Method* y) {
552 if (x->highest_comp_level() > y->highest_comp_level()) {
553 // recompilation after deopt
554 return true;
555 } else
556 if (x->highest_comp_level() == y->highest_comp_level()) {
557 if (weight(x) > weight(y)) {
558 return true;
559 }
560 }
561 return false;
562 }
563
564 // Is method profiled enough?
565 bool TieredThresholdPolicy::is_method_profiled(Method* method) {
566 MethodData* mdo = method->method_data();
567 if (mdo != NULL) {
568 int i = mdo->invocation_count_delta();
569 int b = mdo->backedge_count_delta();
570 return call_predicate_helper<CompLevel_full_profile>(i, b, 1, method);
571 }
572 return false;
573 }
574
575 double TieredThresholdPolicy::threshold_scale(CompLevel level, int feedback_k) {
576 double queue_size = CompileBroker::queue_size(level);
577 int comp_count = compiler_count(level);
578 double k = queue_size / (feedback_k * comp_count) + 1;
579
580 // Increase C1 compile threshold when the code cache is filled more
581 // than specified by IncreaseFirstTierCompileThresholdAt percentage.
582 // The main intention is to keep enough free space for C2 compiled code
583 // to achieve peak performance if the code cache is under stress.
584 if ((TieredStopAtLevel == CompLevel_full_optimization) && (level != CompLevel_full_optimization)) {
585 double current_reverse_free_ratio = CodeCache::reverse_free_ratio(CodeCache::get_code_blob_type(level));
586 if (current_reverse_free_ratio > _increase_threshold_at_ratio) {
587 k *= exp(current_reverse_free_ratio - _increase_threshold_at_ratio);
588 }
589 }
590 return k;
591 }
592
593 // Call and loop predicates determine whether a transition to a higher
594 // compilation level should be performed (pointers to predicate functions
595 // are passed to common()).
596 // Tier?LoadFeedback is basically a coefficient that determines of
597 // how many methods per compiler thread can be in the queue before
598 // the threshold values double.
599 bool TieredThresholdPolicy::loop_predicate(int i, int b, CompLevel cur_level, Method* method) {
600 switch(cur_level) {
601 case CompLevel_aot: {
602 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
603 return loop_predicate_helper<CompLevel_aot>(i, b, k, method);
604 }
605 case CompLevel_none:
606 case CompLevel_limited_profile: {
607 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
608 return loop_predicate_helper<CompLevel_none>(i, b, k, method);
609 }
610 case CompLevel_full_profile: {
611 double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);
612 return loop_predicate_helper<CompLevel_full_profile>(i, b, k, method);
613 }
614 default:
615 return true;
616 }
617 }
618
619 bool TieredThresholdPolicy::call_predicate(int i, int b, CompLevel cur_level, Method* method) {
620 switch(cur_level) {
621 case CompLevel_aot: {
622 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
623 return call_predicate_helper<CompLevel_aot>(i, b, k, method);
624 }
625 case CompLevel_none:
626 case CompLevel_limited_profile: {
627 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
628 return call_predicate_helper<CompLevel_none>(i, b, k, method);
629 }
630 case CompLevel_full_profile: {
631 double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);
632 return call_predicate_helper<CompLevel_full_profile>(i, b, k, method);
633 }
634 default:
635 return true;
636 }
637 }
638
639 // Determine is a method is mature.
640 bool TieredThresholdPolicy::is_mature(Method* method) {
641 if (should_compile_at_level_simple(method)) return true;
642 MethodData* mdo = method->method_data();
643 if (mdo != NULL) {
644 int i = mdo->invocation_count();
645 int b = mdo->backedge_count();
646 double k = ProfileMaturityPercentage / 100.0;
647 return call_predicate_helper<CompLevel_full_profile>(i, b, k, method) ||
648 loop_predicate_helper<CompLevel_full_profile>(i, b, k, method);
649 }
650 return false;
651 }
652
653 // If a method is old enough and is still in the interpreter we would want to
654 // start profiling without waiting for the compiled method to arrive.
655 // We also take the load on compilers into the account.
656 bool TieredThresholdPolicy::should_create_mdo(Method* method, CompLevel cur_level) {
657 if (cur_level == CompLevel_none &&
658 CompileBroker::queue_size(CompLevel_full_optimization) <=
659 Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {
660 int i = method->invocation_count();
661 int b = method->backedge_count();
662 double k = Tier0ProfilingStartPercentage / 100.0;
663 return call_predicate_helper<CompLevel_none>(i, b, k, method) || loop_predicate_helper<CompLevel_none>(i, b, k, method);
664 }
665 return false;
666 }
667
668 // Inlining control: if we're compiling a profiled method with C1 and the callee
669 // is known to have OSRed in a C2 version, don't inline it.
670 bool TieredThresholdPolicy::should_not_inline(ciEnv* env, ciMethod* callee) {
671 CompLevel comp_level = (CompLevel)env->comp_level();
672 if (comp_level == CompLevel_full_profile ||
673 comp_level == CompLevel_limited_profile) {
674 return callee->highest_osr_comp_level() == CompLevel_full_optimization;
675 }
676 return false;
677 }
678
679 // Create MDO if necessary.
680 void TieredThresholdPolicy::create_mdo(const methodHandle& mh, JavaThread* THREAD) {
681 if (mh->is_native() ||
682 mh->is_abstract() ||
683 mh->is_accessor() ||
684 mh->is_constant_getter()) {
685 return;
686 }
687 if (mh->method_data() == NULL) {
688 Method::build_interpreter_method_data(mh, CHECK_AND_CLEAR);
689 }
690 }
691
692
693 /*
694 * Method states:
695 * 0 - interpreter (CompLevel_none)
696 * 1 - pure C1 (CompLevel_simple)
697 * 2 - C1 with invocation and backedge counting (CompLevel_limited_profile)
698 * 3 - C1 with full profiling (CompLevel_full_profile)
699 * 4 - C2 (CompLevel_full_optimization)
700 *
701 * Common state transition patterns:
702 * a. 0 -> 3 -> 4.
703 * The most common path. But note that even in this straightforward case
704 * profiling can start at level 0 and finish at level 3.
705 *
706 * b. 0 -> 2 -> 3 -> 4.
707 * This case occurs when the load on C2 is deemed too high. So, instead of transitioning
708 * into state 3 directly and over-profiling while a method is in the C2 queue we transition to
709 * level 2 and wait until the load on C2 decreases. This path is disabled for OSRs.
710 *
711 * c. 0 -> (3->2) -> 4.
712 * In this case we enqueue a method for compilation at level 3, but the C1 queue is long enough
713 * to enable the profiling to fully occur at level 0. In this case we change the compilation level
714 * of the method to 2 while the request is still in-queue, because it'll allow it to run much faster
715 * without full profiling while c2 is compiling.
716 *
717 * d. 0 -> 3 -> 1 or 0 -> 2 -> 1.
718 * After a method was once compiled with C1 it can be identified as trivial and be compiled to
719 * level 1. These transition can also occur if a method can't be compiled with C2 but can with C1.
720 *
721 * e. 0 -> 4.
722 * This can happen if a method fails C1 compilation (it will still be profiled in the interpreter)
723 * or because of a deopt that didn't require reprofiling (compilation won't happen in this case because
724 * the compiled version already exists).
725 *
726 * Note that since state 0 can be reached from any other state via deoptimization different loops
727 * are possible.
728 *
729 */
730
731 // Common transition function. Given a predicate determines if a method should transition to another level.
732 CompLevel TieredThresholdPolicy::common(Predicate p, Method* method, CompLevel cur_level, bool disable_feedback) {
733 CompLevel next_level = cur_level;
734 int i = method->invocation_count();
735 int b = method->backedge_count();
736
737 if (should_compile_at_level_simple(method)) {
738 next_level = CompLevel_simple;
739 } else {
740 switch(cur_level) {
741 default: break;
742 case CompLevel_aot: {
743 // If we were at full profile level, would we switch to full opt?
744 if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) {
745 next_level = CompLevel_full_optimization;
746 } else if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
747 Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
748 (this->*p)(i, b, cur_level, method))) {
749 next_level = CompLevel_full_profile;
750 }
751 }
752 break;
753 case CompLevel_none:
754 // If we were at full profile level, would we switch to full opt?
755 if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) {
756 next_level = CompLevel_full_optimization;
757 } else if ((this->*p)(i, b, cur_level, method)) {
758 #if INCLUDE_JVMCI
759 if (EnableJVMCI && UseJVMCICompiler) {
760 // Since JVMCI takes a while to warm up, its queue inevitably backs up during
761 // early VM execution. As of 2014-06-13, JVMCI's inliner assumes that the root
762 // compilation method and all potential inlinees have mature profiles (which
763 // includes type profiling). If it sees immature profiles, JVMCI's inliner
764 // can perform pathologically bad (e.g., causing OutOfMemoryErrors due to
765 // exploring/inlining too many graphs). Since a rewrite of the inliner is
766 // in progress, we simply disable the dialing back heuristic for now and will
767 // revisit this decision once the new inliner is completed.
768 next_level = CompLevel_full_profile;
769 } else
770 #endif
771 {
772 // C1-generated fully profiled code is about 30% slower than the limited profile
773 // code that has only invocation and backedge counters. The observation is that
774 // if C2 queue is large enough we can spend too much time in the fully profiled code
775 // while waiting for C2 to pick the method from the queue. To alleviate this problem
776 // we introduce a feedback on the C2 queue size. If the C2 queue is sufficiently long
777 // we choose to compile a limited profiled version and then recompile with full profiling
778 // when the load on C2 goes down.
779 if (!disable_feedback && CompileBroker::queue_size(CompLevel_full_optimization) >
780 Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {
781 next_level = CompLevel_limited_profile;
782 } else {
783 next_level = CompLevel_full_profile;
784 }
785 }
786 }
787 break;
788 case CompLevel_limited_profile:
789 if (is_method_profiled(method)) {
790 // Special case: we got here because this method was fully profiled in the interpreter.
791 next_level = CompLevel_full_optimization;
792 } else {
793 MethodData* mdo = method->method_data();
794 if (mdo != NULL) {
795 if (mdo->would_profile()) {
796 if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
797 Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
798 (this->*p)(i, b, cur_level, method))) {
799 next_level = CompLevel_full_profile;
800 }
801 } else {
802 next_level = CompLevel_full_optimization;
803 }
804 } else {
805 // If there is no MDO we need to profile
806 if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
807 Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
808 (this->*p)(i, b, cur_level, method))) {
809 next_level = CompLevel_full_profile;
810 }
811 }
812 }
813 break;
814 case CompLevel_full_profile:
815 {
816 MethodData* mdo = method->method_data();
817 if (mdo != NULL) {
818 if (mdo->would_profile()) {
819 int mdo_i = mdo->invocation_count_delta();
820 int mdo_b = mdo->backedge_count_delta();
821 if ((this->*p)(mdo_i, mdo_b, cur_level, method)) {
822 next_level = CompLevel_full_optimization;
823 }
824 } else {
825 next_level = CompLevel_full_optimization;
826 }
827 }
828 }
829 break;
830 }
831 }
832 return MIN2(next_level, (CompLevel)TieredStopAtLevel);
833 }
834
835 // Determine if a method should be compiled with a normal entry point at a different level.
836 CompLevel TieredThresholdPolicy::call_event(Method* method, CompLevel cur_level, JavaThread * thread) {
837 CompLevel osr_level = MIN2((CompLevel) method->highest_osr_comp_level(),
838 common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true));
839 CompLevel next_level = common(&TieredThresholdPolicy::call_predicate, method, cur_level);
840
841 // If OSR method level is greater than the regular method level, the levels should be
842 // equalized by raising the regular method level in order to avoid OSRs during each
843 // invocation of the method.
844 if (osr_level == CompLevel_full_optimization && cur_level == CompLevel_full_profile) {
845 MethodData* mdo = method->method_data();
846 guarantee(mdo != NULL, "MDO should not be NULL");
847 if (mdo->invocation_count() >= 1) {
848 next_level = CompLevel_full_optimization;
849 }
850 } else {
851 next_level = MAX2(osr_level, next_level);
852 }
853 return next_level;
854 }
855
856 // Determine if we should do an OSR compilation of a given method.
857 CompLevel TieredThresholdPolicy::loop_event(Method* method, CompLevel cur_level, JavaThread* thread) {
858 CompLevel next_level = common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true);
859 if (cur_level == CompLevel_none) {
860 // If there is a live OSR method that means that we deopted to the interpreter
861 // for the transition.
862 CompLevel osr_level = MIN2((CompLevel)method->highest_osr_comp_level(), next_level);
863 if (osr_level > CompLevel_none) {
864 return osr_level;
865 }
866 }
867 return next_level;
868 }
869
870 bool TieredThresholdPolicy::maybe_switch_to_aot(const methodHandle& mh, CompLevel cur_level, CompLevel next_level, JavaThread* thread) {
871 if (UseAOT) {
872 if (cur_level == CompLevel_full_profile || cur_level == CompLevel_none) {
873 // If the current level is full profile or interpreter and we're switching to any other level,
874 // activate the AOT code back first so that we won't waste time overprofiling.
875 compile(mh, InvocationEntryBci, CompLevel_aot, thread);
876 // Fall through for JIT compilation.
877 }
878 if (next_level == CompLevel_limited_profile && cur_level != CompLevel_aot && mh->has_aot_code()) {
879 // If the next level is limited profile, use the aot code (if there is any),
880 // since it's essentially the same thing.
881 compile(mh, InvocationEntryBci, CompLevel_aot, thread);
882 // Not need to JIT, we're done.
883 return true;
884 }
885 }
886 return false;
887 }
888
889
890 // Handle the invocation event.
891 void TieredThresholdPolicy::method_invocation_event(const methodHandle& mh, const methodHandle& imh,
892 CompLevel level, CompiledMethod* nm, JavaThread* thread) {
893 if (should_create_mdo(mh(), level)) {
894 create_mdo(mh, thread);
895 }
896 CompLevel next_level = call_event(mh(), level, thread);
897 if (next_level != level) {
898 if (maybe_switch_to_aot(mh, level, next_level, thread)) {
899 // No JITting necessary
900 return;
901 }
902 if (is_compilation_enabled() && !CompileBroker::compilation_is_in_queue(mh)) {
903 compile(mh, InvocationEntryBci, next_level, thread);
904 }
905 }
906 }
907
908 // Handle the back branch event. Notice that we can compile the method
909 // with a regular entry from here.
910 void TieredThresholdPolicy::method_back_branch_event(const methodHandle& mh, const methodHandle& imh,
911 int bci, CompLevel level, CompiledMethod* nm, JavaThread* thread) {
912 if (should_create_mdo(mh(), level)) {
913 create_mdo(mh, thread);
914 }
915 // Check if MDO should be created for the inlined method
916 if (should_create_mdo(imh(), level)) {
917 create_mdo(imh, thread);
918 }
919
920 if (is_compilation_enabled()) {
921 CompLevel next_osr_level = loop_event(imh(), level, thread);
922 CompLevel max_osr_level = (CompLevel)imh->highest_osr_comp_level();
923 // At the very least compile the OSR version
924 if (!CompileBroker::compilation_is_in_queue(imh) && (next_osr_level != level)) {
925 compile(imh, bci, next_osr_level, thread);
926 }
927
928 // Use loop event as an opportunity to also check if there's been
929 // enough calls.
930 CompLevel cur_level, next_level;
931 if (mh() != imh()) { // If there is an enclosing method
932 if (level == CompLevel_aot) {
933 // Recompile the enclosing method to prevent infinite OSRs. Stay at AOT level while it's compiling.
934 if (max_osr_level != CompLevel_none && !CompileBroker::compilation_is_in_queue(mh)) {
935 compile(mh, InvocationEntryBci, MIN2((CompLevel)TieredStopAtLevel, CompLevel_full_profile), thread);
936 }
937 } else {
938 // Current loop event level is not AOT
939 guarantee(nm != NULL, "Should have nmethod here");
940 cur_level = comp_level(mh());
941 next_level = call_event(mh(), cur_level, thread);
942
943 if (max_osr_level == CompLevel_full_optimization) {
944 // The inlinee OSRed to full opt, we need to modify the enclosing method to avoid deopts
945 bool make_not_entrant = false;
946 if (nm->is_osr_method()) {
947 // This is an osr method, just make it not entrant and recompile later if needed
948 make_not_entrant = true;
949 } else {
950 if (next_level != CompLevel_full_optimization) {
951 // next_level is not full opt, so we need to recompile the
952 // enclosing method without the inlinee
953 cur_level = CompLevel_none;
954 make_not_entrant = true;
955 }
956 }
957 if (make_not_entrant) {
958 if (PrintTieredEvents) {
959 int osr_bci = nm->is_osr_method() ? nm->osr_entry_bci() : InvocationEntryBci;
960 print_event(MAKE_NOT_ENTRANT, mh(), mh(), osr_bci, level);
961 }
962 nm->make_not_entrant();
963 }
964 }
965 // Fix up next_level if necessary to avoid deopts
966 if (next_level == CompLevel_limited_profile && max_osr_level == CompLevel_full_profile) {
967 next_level = CompLevel_full_profile;
968 }
969 if (cur_level != next_level) {
970 if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) {
971 compile(mh, InvocationEntryBci, next_level, thread);
972 }
973 }
974 }
975 } else {
976 cur_level = comp_level(mh());
977 next_level = call_event(mh(), cur_level, thread);
978 if (next_level != cur_level) {
979 if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) {
980 compile(mh, InvocationEntryBci, next_level, thread);
981 }
982 }
983 }
984 }
985 }
986
987 #endif