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 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_intptr(os::active_processor_count());
230 int loglog_cpu = log2_intptr(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 if (PrintTieredEvents) {
361 print_event(UPDATE_IN_QUEUE, max_method, max_method, max_task->osr_bci(), (CompLevel)max_task->comp_level());
362 }
363 }
364
365 return max_task;
366 }
367
368 void TieredThresholdPolicy::reprofile(ScopeDesc* trap_scope, bool is_osr) {
369 for (ScopeDesc* sd = trap_scope;; sd = sd->sender()) {
370 if (PrintTieredEvents) {
371 methodHandle mh(sd->method());
372 print_event(REPROFILE, mh, mh, InvocationEntryBci, CompLevel_none);
373 }
374 MethodData* mdo = sd->method()->method_data();
375 if (mdo != NULL) {
376 mdo->reset_start_counters();
377 }
378 if (sd->is_top()) break;
379 }
380 }
381
382 nmethod* TieredThresholdPolicy::event(const methodHandle& method, const methodHandle& inlinee,
383 int branch_bci, int bci, CompLevel comp_level, CompiledMethod* nm, JavaThread* thread) {
384 if (comp_level == CompLevel_none &&
385 JvmtiExport::can_post_interpreter_events() &&
386 thread->is_interp_only_mode()) {
387 return NULL;
388 }
389 if (CompileTheWorld || ReplayCompiles) {
390 // Don't trigger other compiles in testing mode
391 return NULL;
392 }
393
394 handle_counter_overflow(method());
395 if (method() != inlinee()) {
396 handle_counter_overflow(inlinee());
397 }
398
399 if (PrintTieredEvents) {
400 print_event(bci == InvocationEntryBci ? CALL : LOOP, method, inlinee, bci, comp_level);
401 }
402
403 if (bci == InvocationEntryBci) {
404 method_invocation_event(method, inlinee, comp_level, nm, thread);
405 } else {
406 // method == inlinee if the event originated in the main method
407 method_back_branch_event(method, inlinee, bci, comp_level, nm, thread);
408 // Check if event led to a higher level OSR compilation
409 nmethod* osr_nm = inlinee->lookup_osr_nmethod_for(bci, comp_level, false);
410 if (osr_nm != NULL && osr_nm->comp_level() > comp_level) {
411 // Perform OSR with new nmethod
412 return osr_nm;
413 }
414 }
415 return NULL;
416 }
417
418 // Check if the method can be compiled, change level if necessary
419 void TieredThresholdPolicy::compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) {
420 assert(level <= TieredStopAtLevel, "Invalid compilation level");
421 if (level == CompLevel_none) {
422 return;
423 }
424 if (level == CompLevel_aot) {
425 if (mh->has_aot_code()) {
426 if (PrintTieredEvents) {
427 print_event(COMPILE, mh, mh, bci, level);
428 }
429 MutexLocker ml(Compile_lock);
430 NoSafepointVerifier nsv;
431 if (mh->has_aot_code() && mh->code() != mh->aot_code()) {
432 mh->aot_code()->make_entrant();
433 if (mh->has_compiled_code()) {
434 mh->code()->make_not_entrant();
435 }
436 Method::set_code(mh, mh->aot_code());
437 }
438 }
439 return;
440 }
441
442 // Check if the method can be compiled. If it cannot be compiled with C1, continue profiling
443 // in the interpreter and then compile with C2 (the transition function will request that,
444 // see common() ). If the method cannot be compiled with C2 but still can with C1, compile it with
445 // pure C1.
446 if (!can_be_compiled(mh, level)) {
447 if (level == CompLevel_full_optimization && can_be_compiled(mh, CompLevel_simple)) {
448 compile(mh, bci, CompLevel_simple, thread);
449 }
450 return;
451 }
452 if (bci != InvocationEntryBci && mh->is_not_osr_compilable(level)) {
453 return;
454 }
455 if (!CompileBroker::compilation_is_in_queue(mh)) {
456 if (PrintTieredEvents) {
457 print_event(COMPILE, mh, mh, bci, level);
458 }
459 submit_compile(mh, bci, level, thread);
460 }
461 }
462
463 // Update the rate and submit compile
464 void TieredThresholdPolicy::submit_compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) {
465 int hot_count = (bci == InvocationEntryBci) ? mh->invocation_count() : mh->backedge_count();
466 update_rate(os::javaTimeMillis(), mh());
467 CompileBroker::compile_method(mh, bci, level, mh, hot_count, CompileTask::Reason_Tiered, thread);
468 }
469
470 // Print an event.
471 void TieredThresholdPolicy::print_specific(EventType type, const methodHandle& mh, const methodHandle& imh,
472 int bci, CompLevel level) {
473 tty->print(" rate=");
474 if (mh->prev_time() == 0) tty->print("n/a");
475 else tty->print("%f", mh->rate());
476
477 tty->print(" k=%.2lf,%.2lf", threshold_scale(CompLevel_full_profile, Tier3LoadFeedback),
478 threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback));
479
480 }
481
482 // update_rate() is called from select_task() while holding a compile queue lock.
483 void TieredThresholdPolicy::update_rate(jlong t, Method* m) {
484 // Skip update if counters are absent.
485 // Can't allocate them since we are holding compile queue lock.
486 if (m->method_counters() == NULL) return;
487
488 if (is_old(m)) {
489 // We don't remove old methods from the queue,
490 // so we can just zero the rate.
491 m->set_rate(0);
492 return;
493 }
494
495 // We don't update the rate if we've just came out of a safepoint.
496 // delta_s is the time since last safepoint in milliseconds.
497 jlong delta_s = t - SafepointSynchronize::end_of_last_safepoint();
498 jlong delta_t = t - (m->prev_time() != 0 ? m->prev_time() : start_time()); // milliseconds since the last measurement
499 // How many events were there since the last time?
500 int event_count = m->invocation_count() + m->backedge_count();
501 int delta_e = event_count - m->prev_event_count();
502
503 // We should be running for at least 1ms.
504 if (delta_s >= TieredRateUpdateMinTime) {
505 // And we must've taken the previous point at least 1ms before.
506 if (delta_t >= TieredRateUpdateMinTime && delta_e > 0) {
507 m->set_prev_time(t);
508 m->set_prev_event_count(event_count);
509 m->set_rate((float)delta_e / (float)delta_t); // Rate is events per millisecond
510 } else {
511 if (delta_t > TieredRateUpdateMaxTime && delta_e == 0) {
512 // If nothing happened for 25ms, zero the rate. Don't modify prev values.
513 m->set_rate(0);
514 }
515 }
516 }
517 }
518
519 // Check if this method has been stale from a given number of milliseconds.
520 // See select_task().
521 bool TieredThresholdPolicy::is_stale(jlong t, jlong timeout, Method* m) {
522 jlong delta_s = t - SafepointSynchronize::end_of_last_safepoint();
523 jlong delta_t = t - m->prev_time();
524 if (delta_t > timeout && delta_s > timeout) {
525 int event_count = m->invocation_count() + m->backedge_count();
526 int delta_e = event_count - m->prev_event_count();
527 // Return true if there were no events.
528 return delta_e == 0;
529 }
530 return false;
531 }
532
533 // We don't remove old methods from the compile queue even if they have
534 // very low activity. See select_task().
535 bool TieredThresholdPolicy::is_old(Method* method) {
536 return method->invocation_count() > 50000 || method->backedge_count() > 500000;
537 }
538
539 double TieredThresholdPolicy::weight(Method* method) {
540 return (double)(method->rate() + 1) *
541 (method->invocation_count() + 1) * (method->backedge_count() + 1);
542 }
543
544 // Apply heuristics and return true if x should be compiled before y
545 bool TieredThresholdPolicy::compare_methods(Method* x, Method* y) {
546 if (x->highest_comp_level() > y->highest_comp_level()) {
547 // recompilation after deopt
548 return true;
549 } else
550 if (x->highest_comp_level() == y->highest_comp_level()) {
551 if (weight(x) > weight(y)) {
552 return true;
553 }
554 }
555 return false;
556 }
557
558 // Is method profiled enough?
559 bool TieredThresholdPolicy::is_method_profiled(Method* method) {
560 MethodData* mdo = method->method_data();
561 if (mdo != NULL) {
562 int i = mdo->invocation_count_delta();
563 int b = mdo->backedge_count_delta();
564 return call_predicate_helper<CompLevel_full_profile>(i, b, 1, method);
565 }
566 return false;
567 }
568
569 double TieredThresholdPolicy::threshold_scale(CompLevel level, int feedback_k) {
570 double queue_size = CompileBroker::queue_size(level);
571 int comp_count = compiler_count(level);
572 double k = queue_size / (feedback_k * comp_count) + 1;
573
574 // Increase C1 compile threshold when the code cache is filled more
575 // than specified by IncreaseFirstTierCompileThresholdAt percentage.
576 // The main intention is to keep enough free space for C2 compiled code
577 // to achieve peak performance if the code cache is under stress.
578 if ((TieredStopAtLevel == CompLevel_full_optimization) && (level != CompLevel_full_optimization)) {
579 double current_reverse_free_ratio = CodeCache::reverse_free_ratio(CodeCache::get_code_blob_type(level));
580 if (current_reverse_free_ratio > _increase_threshold_at_ratio) {
581 k *= exp(current_reverse_free_ratio - _increase_threshold_at_ratio);
582 }
583 }
584 return k;
585 }
586
587 // Call and loop predicates determine whether a transition to a higher
588 // compilation level should be performed (pointers to predicate functions
589 // are passed to common()).
590 // Tier?LoadFeedback is basically a coefficient that determines of
591 // how many methods per compiler thread can be in the queue before
592 // the threshold values double.
593 bool TieredThresholdPolicy::loop_predicate(int i, int b, CompLevel cur_level, Method* method) {
594 switch(cur_level) {
595 case CompLevel_aot: {
596 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
597 return loop_predicate_helper<CompLevel_aot>(i, b, k, method);
598 }
599 case CompLevel_none:
600 case CompLevel_limited_profile: {
601 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
602 return loop_predicate_helper<CompLevel_none>(i, b, k, method);
603 }
604 case CompLevel_full_profile: {
605 double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);
606 return loop_predicate_helper<CompLevel_full_profile>(i, b, k, method);
607 }
608 default:
609 return true;
610 }
611 }
612
613 bool TieredThresholdPolicy::call_predicate(int i, int b, CompLevel cur_level, Method* method) {
614 switch(cur_level) {
615 case CompLevel_aot: {
616 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
617 return call_predicate_helper<CompLevel_aot>(i, b, k, method);
618 }
619 case CompLevel_none:
620 case CompLevel_limited_profile: {
621 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
622 return call_predicate_helper<CompLevel_none>(i, b, k, method);
623 }
624 case CompLevel_full_profile: {
625 double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);
626 return call_predicate_helper<CompLevel_full_profile>(i, b, k, method);
627 }
628 default:
629 return true;
630 }
631 }
632
633 // Determine is a method is mature.
634 bool TieredThresholdPolicy::is_mature(Method* method) {
635 if (is_trivial(method)) return true;
636 MethodData* mdo = method->method_data();
637 if (mdo != NULL) {
638 int i = mdo->invocation_count();
639 int b = mdo->backedge_count();
640 double k = ProfileMaturityPercentage / 100.0;
641 return call_predicate_helper<CompLevel_full_profile>(i, b, k, method) ||
642 loop_predicate_helper<CompLevel_full_profile>(i, b, k, method);
643 }
644 return false;
645 }
646
647 // If a method is old enough and is still in the interpreter we would want to
648 // start profiling without waiting for the compiled method to arrive.
649 // We also take the load on compilers into the account.
650 bool TieredThresholdPolicy::should_create_mdo(Method* method, CompLevel cur_level) {
651 if (cur_level == CompLevel_none &&
652 CompileBroker::queue_size(CompLevel_full_optimization) <=
653 Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {
654 int i = method->invocation_count();
655 int b = method->backedge_count();
656 double k = Tier0ProfilingStartPercentage / 100.0;
657 return call_predicate_helper<CompLevel_none>(i, b, k, method) || loop_predicate_helper<CompLevel_none>(i, b, k, method);
658 }
659 return false;
660 }
661
662 // Inlining control: if we're compiling a profiled method with C1 and the callee
663 // is known to have OSRed in a C2 version, don't inline it.
664 bool TieredThresholdPolicy::should_not_inline(ciEnv* env, ciMethod* callee) {
665 CompLevel comp_level = (CompLevel)env->comp_level();
666 if (comp_level == CompLevel_full_profile ||
667 comp_level == CompLevel_limited_profile) {
668 return callee->highest_osr_comp_level() == CompLevel_full_optimization;
669 }
670 return false;
671 }
672
673 // Create MDO if necessary.
674 void TieredThresholdPolicy::create_mdo(const methodHandle& mh, JavaThread* THREAD) {
675 if (mh->is_native() ||
676 mh->is_abstract() ||
677 mh->is_accessor() ||
678 mh->is_constant_getter()) {
679 return;
680 }
681 if (mh->method_data() == NULL) {
682 Method::build_interpreter_method_data(mh, CHECK_AND_CLEAR);
683 }
684 }
685
686
687 /*
688 * Method states:
689 * 0 - interpreter (CompLevel_none)
690 * 1 - pure C1 (CompLevel_simple)
691 * 2 - C1 with invocation and backedge counting (CompLevel_limited_profile)
692 * 3 - C1 with full profiling (CompLevel_full_profile)
693 * 4 - C2 (CompLevel_full_optimization)
694 *
695 * Common state transition patterns:
696 * a. 0 -> 3 -> 4.
697 * The most common path. But note that even in this straightforward case
698 * profiling can start at level 0 and finish at level 3.
699 *
700 * b. 0 -> 2 -> 3 -> 4.
701 * This case occurs when the load on C2 is deemed too high. So, instead of transitioning
702 * into state 3 directly and over-profiling while a method is in the C2 queue we transition to
703 * level 2 and wait until the load on C2 decreases. This path is disabled for OSRs.
704 *
705 * c. 0 -> (3->2) -> 4.
706 * In this case we enqueue a method for compilation at level 3, but the C1 queue is long enough
707 * to enable the profiling to fully occur at level 0. In this case we change the compilation level
708 * of the method to 2 while the request is still in-queue, because it'll allow it to run much faster
709 * without full profiling while c2 is compiling.
710 *
711 * d. 0 -> 3 -> 1 or 0 -> 2 -> 1.
712 * After a method was once compiled with C1 it can be identified as trivial and be compiled to
713 * level 1. These transition can also occur if a method can't be compiled with C2 but can with C1.
714 *
715 * e. 0 -> 4.
716 * This can happen if a method fails C1 compilation (it will still be profiled in the interpreter)
717 * or because of a deopt that didn't require reprofiling (compilation won't happen in this case because
718 * the compiled version already exists).
719 *
720 * Note that since state 0 can be reached from any other state via deoptimization different loops
721 * are possible.
722 *
723 */
724
725 // Common transition function. Given a predicate determines if a method should transition to another level.
726 CompLevel TieredThresholdPolicy::common(Predicate p, Method* method, CompLevel cur_level, bool disable_feedback) {
727 CompLevel next_level = cur_level;
728 int i = method->invocation_count();
729 int b = method->backedge_count();
730
731 if (is_trivial(method)) {
732 next_level = CompLevel_simple;
733 } else {
734 switch(cur_level) {
735 default: break;
736 case CompLevel_aot: {
737 // If we were at full profile level, would we switch to full opt?
738 if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) {
739 next_level = CompLevel_full_optimization;
740 } else if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
741 Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
742 (this->*p)(i, b, cur_level, method))) {
743 next_level = CompLevel_full_profile;
744 }
745 }
746 break;
747 case CompLevel_none:
748 // If we were at full profile level, would we switch to full opt?
749 if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) {
750 next_level = CompLevel_full_optimization;
751 } else if ((this->*p)(i, b, cur_level, method)) {
752 #if INCLUDE_JVMCI
753 if (EnableJVMCI && UseJVMCICompiler) {
754 // Since JVMCI takes a while to warm up, its queue inevitably backs up during
755 // early VM execution. As of 2014-06-13, JVMCI's inliner assumes that the root
756 // compilation method and all potential inlinees have mature profiles (which
757 // includes type profiling). If it sees immature profiles, JVMCI's inliner
758 // can perform pathologically bad (e.g., causing OutOfMemoryErrors due to
759 // exploring/inlining too many graphs). Since a rewrite of the inliner is
760 // in progress, we simply disable the dialing back heuristic for now and will
761 // revisit this decision once the new inliner is completed.
762 next_level = CompLevel_full_profile;
763 } else
764 #endif
765 {
766 // C1-generated fully profiled code is about 30% slower than the limited profile
767 // code that has only invocation and backedge counters. The observation is that
768 // if C2 queue is large enough we can spend too much time in the fully profiled code
769 // while waiting for C2 to pick the method from the queue. To alleviate this problem
770 // we introduce a feedback on the C2 queue size. If the C2 queue is sufficiently long
771 // we choose to compile a limited profiled version and then recompile with full profiling
772 // when the load on C2 goes down.
773 if (!disable_feedback && CompileBroker::queue_size(CompLevel_full_optimization) >
774 Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {
775 next_level = CompLevel_limited_profile;
776 } else {
777 next_level = CompLevel_full_profile;
778 }
779 }
780 }
781 break;
782 case CompLevel_limited_profile:
783 if (is_method_profiled(method)) {
784 // Special case: we got here because this method was fully profiled in the interpreter.
785 next_level = CompLevel_full_optimization;
786 } else {
787 MethodData* mdo = method->method_data();
788 if (mdo != NULL) {
789 if (mdo->would_profile()) {
790 if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
791 Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
792 (this->*p)(i, b, cur_level, method))) {
793 next_level = CompLevel_full_profile;
794 }
795 } else {
796 next_level = CompLevel_full_optimization;
797 }
798 } else {
799 // If there is no MDO we need to 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 }
806 }
807 break;
808 case CompLevel_full_profile:
809 {
810 MethodData* mdo = method->method_data();
811 if (mdo != NULL) {
812 if (mdo->would_profile()) {
813 int mdo_i = mdo->invocation_count_delta();
814 int mdo_b = mdo->backedge_count_delta();
815 if ((this->*p)(mdo_i, mdo_b, cur_level, method)) {
816 next_level = CompLevel_full_optimization;
817 }
818 } else {
819 next_level = CompLevel_full_optimization;
820 }
821 }
822 }
823 break;
824 }
825 }
826 return MIN2(next_level, (CompLevel)TieredStopAtLevel);
827 }
828
829 // Determine if a method should be compiled with a normal entry point at a different level.
830 CompLevel TieredThresholdPolicy::call_event(Method* method, CompLevel cur_level, JavaThread * thread) {
831 CompLevel osr_level = MIN2((CompLevel) method->highest_osr_comp_level(),
832 common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true));
833 CompLevel next_level = common(&TieredThresholdPolicy::call_predicate, method, cur_level);
834
835 // If OSR method level is greater than the regular method level, the levels should be
836 // equalized by raising the regular method level in order to avoid OSRs during each
837 // invocation of the method.
838 if (osr_level == CompLevel_full_optimization && cur_level == CompLevel_full_profile) {
839 MethodData* mdo = method->method_data();
840 guarantee(mdo != NULL, "MDO should not be NULL");
841 if (mdo->invocation_count() >= 1) {
842 next_level = CompLevel_full_optimization;
843 }
844 } else {
845 next_level = MAX2(osr_level, next_level);
846 }
847 #if INCLUDE_JVMCI
848 if (UseJVMCICompiler) {
849 next_level = JVMCIRuntime::adjust_comp_level(method, false, next_level, thread);
850 }
851 #endif
852 return next_level;
853 }
854
855 // Determine if we should do an OSR compilation of a given method.
856 CompLevel TieredThresholdPolicy::loop_event(Method* method, CompLevel cur_level, JavaThread* thread) {
857 CompLevel next_level = common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true);
858 if (cur_level == CompLevel_none) {
859 // If there is a live OSR method that means that we deopted to the interpreter
860 // for the transition.
861 CompLevel osr_level = MIN2((CompLevel)method->highest_osr_comp_level(), next_level);
862 if (osr_level > CompLevel_none) {
863 return osr_level;
864 }
865 }
866 #if INCLUDE_JVMCI
867 if (UseJVMCICompiler) {
868 next_level = JVMCIRuntime::adjust_comp_level(method, true, next_level, thread);
869 }
870 #endif
871 return next_level;
872 }
873
874 bool TieredThresholdPolicy::maybe_switch_to_aot(const methodHandle& mh, CompLevel cur_level, CompLevel next_level, JavaThread* thread) {
875 if (UseAOT && !delay_compilation_during_startup()) {
876 if (cur_level == CompLevel_full_profile || cur_level == CompLevel_none) {
877 // If the current level is full profile or interpreter and we're switching to any other level,
878 // activate the AOT code back first so that we won't waste time overprofiling.
879 compile(mh, InvocationEntryBci, CompLevel_aot, thread);
880 // Fall through for JIT compilation.
881 }
882 if (next_level == CompLevel_limited_profile && cur_level != CompLevel_aot && mh->has_aot_code()) {
883 // If the next level is limited profile, use the aot code (if there is any),
884 // since it's essentially the same thing.
885 compile(mh, InvocationEntryBci, CompLevel_aot, thread);
886 // Not need to JIT, we're done.
887 return true;
888 }
889 }
890 return false;
891 }
892
893
894 // Handle the invocation event.
895 void TieredThresholdPolicy::method_invocation_event(const methodHandle& mh, const methodHandle& imh,
896 CompLevel level, CompiledMethod* nm, JavaThread* thread) {
897 if (should_create_mdo(mh(), level)) {
898 create_mdo(mh, thread);
899 }
900 CompLevel next_level = call_event(mh(), level, thread);
901 if (next_level != level) {
902 if (maybe_switch_to_aot(mh, level, next_level, thread)) {
903 // No JITting necessary
904 return;
905 }
906 if (is_compilation_enabled() && !CompileBroker::compilation_is_in_queue(mh)) {
907 compile(mh, InvocationEntryBci, next_level, thread);
908 }
909 }
910 }
911
912 // Handle the back branch event. Notice that we can compile the method
913 // with a regular entry from here.
914 void TieredThresholdPolicy::method_back_branch_event(const methodHandle& mh, const methodHandle& imh,
915 int bci, CompLevel level, CompiledMethod* nm, JavaThread* thread) {
916 if (should_create_mdo(mh(), level)) {
917 create_mdo(mh, thread);
918 }
919 // Check if MDO should be created for the inlined method
920 if (should_create_mdo(imh(), level)) {
921 create_mdo(imh, thread);
922 }
923
924 if (is_compilation_enabled()) {
925 CompLevel next_osr_level = loop_event(imh(), level, thread);
926 CompLevel max_osr_level = (CompLevel)imh->highest_osr_comp_level();
927 // At the very least compile the OSR version
928 if (!CompileBroker::compilation_is_in_queue(imh) && (next_osr_level != level)) {
929 compile(imh, bci, next_osr_level, thread);
930 }
931
932 // Use loop event as an opportunity to also check if there's been
933 // enough calls.
934 CompLevel cur_level, next_level;
935 if (mh() != imh()) { // If there is an enclosing method
936 if (level == CompLevel_aot) {
937 // Recompile the enclosing method to prevent infinite OSRs. Stay at AOT level while it's compiling.
938 if (max_osr_level != CompLevel_none && !CompileBroker::compilation_is_in_queue(mh)) {
939 compile(mh, InvocationEntryBci, MIN2((CompLevel)TieredStopAtLevel, CompLevel_full_profile), thread);
940 }
941 } else {
942 // Current loop event level is not AOT
943 guarantee(nm != NULL, "Should have nmethod here");
944 cur_level = comp_level(mh());
945 next_level = call_event(mh(), cur_level, thread);
946
947 if (max_osr_level == CompLevel_full_optimization) {
948 // The inlinee OSRed to full opt, we need to modify the enclosing method to avoid deopts
949 bool make_not_entrant = false;
950 if (nm->is_osr_method()) {
951 // This is an osr method, just make it not entrant and recompile later if needed
952 make_not_entrant = true;
953 } else {
954 if (next_level != CompLevel_full_optimization) {
955 // next_level is not full opt, so we need to recompile the
956 // enclosing method without the inlinee
957 cur_level = CompLevel_none;
958 make_not_entrant = true;
959 }
960 }
961 if (make_not_entrant) {
962 if (PrintTieredEvents) {
963 int osr_bci = nm->is_osr_method() ? nm->osr_entry_bci() : InvocationEntryBci;
964 print_event(MAKE_NOT_ENTRANT, mh(), mh(), osr_bci, level);
965 }
966 nm->make_not_entrant();
967 }
968 }
969 // Fix up next_level if necessary to avoid deopts
970 if (next_level == CompLevel_limited_profile && max_osr_level == CompLevel_full_profile) {
971 next_level = CompLevel_full_profile;
972 }
973 if (cur_level != next_level) {
974 if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) {
975 compile(mh, InvocationEntryBci, next_level, thread);
976 }
977 }
978 }
979 } else {
980 cur_level = comp_level(mh());
981 next_level = call_event(mh(), cur_level, thread);
982 if (next_level != cur_level) {
983 if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) {
984 compile(mh, InvocationEntryBci, next_level, thread);
985 }
986 }
987 }
988 }
989 }
990
991 #endif