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 "code/codeCache.hpp"

    27 #include "runtime/advancedThresholdPolicy.hpp"

    28 #include "runtime/handles.inline.hpp"

    29 #include "runtime/simpleThresholdPolicy.inline.hpp"

    30 #if INCLUDE_JVMCI

    31 #include "jvmci/jvmciRuntime.hpp"

    32 #endif

    33 

    34 #ifdef TIERED

    35 // Print an event.

    36 void AdvancedThresholdPolicy::print_specific(EventType type, const methodHandle& mh, const methodHandle& imh,

    37                                              int bci, CompLevel level) {

    38   tty->print(" rate=");

    39   if (mh->prev_time() == 0) tty->print("n/a");

    40   else tty->print("%f", mh->rate());

    41 

    42   tty->print(" k=%.2lf,%.2lf", threshold_scale(CompLevel_full_profile, Tier3LoadFeedback),

    43                                threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback));

    44 

    45 }

    46 

    47 void AdvancedThresholdPolicy::initialize() {

    48   int count = CICompilerCount;

    49 #ifdef _LP64

    50   // Turn on ergonomic compiler count selection

    51   if (FLAG_IS_DEFAULT(CICompilerCountPerCPU) && FLAG_IS_DEFAULT(CICompilerCount)) {

    52     FLAG_SET_DEFAULT(CICompilerCountPerCPU, true);

    53   }

    54   if (CICompilerCountPerCPU) {

    55     // Simple log n seems to grow too slowly for tiered, try something faster: log n * log log n

    56     int log_cpu = log2_intptr(os::active_processor_count());

    57     int loglog_cpu = log2_intptr(MAX2(log_cpu, 1));

    58     count = MAX2(log_cpu * loglog_cpu * 3 / 2, 2);

    59     FLAG_SET_ERGO(intx, CICompilerCount, count);

    60   }

    61 #else

    62   // On 32-bit systems, the number of compiler threads is limited to 3.

    63   // On these systems, the virtual address space available to the JVM

    64   // is usually limited to 2-4 GB (the exact value depends on the platform).

    65   // As the compilers (especially C2) can consume a large amount of

    66   // memory, scaling the number of compiler threads with the number of

    67   // available cores can result in the exhaustion of the address space

    68   /// available to the VM and thus cause the VM to crash.

    69   if (FLAG_IS_DEFAULT(CICompilerCount)) {

    70     count = 3;

    71     FLAG_SET_ERGO(intx, CICompilerCount, count);

    72   }

    73 #endif

    74 

    75   if (TieredStopAtLevel < CompLevel_full_optimization) {

    76     // No C2 compiler thread required

    77     set_c1_count(count);

    78   } else {

    79     set_c1_count(MAX2(count / 3, 1));

    80     set_c2_count(MAX2(count - c1_count(), 1));

    81   }

    82   assert(count == c1_count() + c2_count(), "inconsistent compiler thread count");

    83 

    84   // Some inlining tuning

    85 #ifdef X86

    86   if (FLAG_IS_DEFAULT(InlineSmallCode)) {

    87     FLAG_SET_DEFAULT(InlineSmallCode, 2000);

    88   }

    89 #endif

    90 

    91 #if defined SPARC || defined AARCH64

    92   if (FLAG_IS_DEFAULT(InlineSmallCode)) {

    93     FLAG_SET_DEFAULT(InlineSmallCode, 2500);

    94   }

    95 #endif

    96 

    97   set_increase_threshold_at_ratio();

    98   set_start_time(os::javaTimeMillis());

    99 }

   100 

   101 // update_rate() is called from select_task() while holding a compile queue lock.

   102 void AdvancedThresholdPolicy::update_rate(jlong t, Method* m) {

   103   // Skip update if counters are absent.

   104   // Can't allocate them since we are holding compile queue lock.

   105   if (m->method_counters() == NULL)  return;

   106 

   107   if (is_old(m)) {

   108     // We don't remove old methods from the queue,

   109     // so we can just zero the rate.

   110     m->set_rate(0);

   111     return;

   112   }

   113 

   114   // We don't update the rate if we've just came out of a safepoint.

   115   // delta_s is the time since last safepoint in milliseconds.

   116   jlong delta_s = t - SafepointSynchronize::end_of_last_safepoint();

   117   jlong delta_t = t - (m->prev_time() != 0 ? m->prev_time() : start_time()); // milliseconds since the last measurement

   118   // How many events were there since the last time?

   119   int event_count = m->invocation_count() + m->backedge_count();

   120   int delta_e = event_count - m->prev_event_count();

   121 

   122   // We should be running for at least 1ms.

   123   if (delta_s >= TieredRateUpdateMinTime) {

   124     // And we must've taken the previous point at least 1ms before.

   125     if (delta_t >= TieredRateUpdateMinTime && delta_e > 0) {

   126       m->set_prev_time(t);

   127       m->set_prev_event_count(event_count);

   128       m->set_rate((float)delta_e / (float)delta_t); // Rate is events per millisecond

   129     } else {

   130       if (delta_t > TieredRateUpdateMaxTime && delta_e == 0) {

   131         // If nothing happened for 25ms, zero the rate. Don't modify prev values.

   132         m->set_rate(0);

   133       }

   134     }

   135   }

   136 }

   137 

   138 // Check if this method has been stale from a given number of milliseconds.

   139 // See select_task().

   140 bool AdvancedThresholdPolicy::is_stale(jlong t, jlong timeout, Method* m) {

   141   jlong delta_s = t - SafepointSynchronize::end_of_last_safepoint();

   142   jlong delta_t = t - m->prev_time();

   143   if (delta_t > timeout && delta_s > timeout) {

   144     int event_count = m->invocation_count() + m->backedge_count();

   145     int delta_e = event_count - m->prev_event_count();

   146     // Return true if there were no events.

   147     return delta_e == 0;

   148   }

   149   return false;

   150 }

   151 

   152 // We don't remove old methods from the compile queue even if they have

   153 // very low activity. See select_task().

   154 bool AdvancedThresholdPolicy::is_old(Method* method) {

   155   return method->invocation_count() > 50000 || method->backedge_count() > 500000;

   156 }

   157 

   158 double AdvancedThresholdPolicy::weight(Method* method) {

   159   return (double)(method->rate() + 1) *

   160     (method->invocation_count() + 1) * (method->backedge_count() + 1);

   161 }

   162 

   163 // Apply heuristics and return true if x should be compiled before y

   164 bool AdvancedThresholdPolicy::compare_methods(Method* x, Method* y) {

   165   if (x->highest_comp_level() > y->highest_comp_level()) {

   166     // recompilation after deopt

   167     return true;

   168   } else

   169     if (x->highest_comp_level() == y->highest_comp_level()) {

   170       if (weight(x) > weight(y)) {

   171         return true;

   172       }

   173     }

   174   return false;

   175 }

   176 

   177 // Is method profiled enough?

   178 bool AdvancedThresholdPolicy::is_method_profiled(Method* method) {

   179   MethodData* mdo = method->method_data();

   180   if (mdo != NULL) {

   181     int i = mdo->invocation_count_delta();

   182     int b = mdo->backedge_count_delta();

   183     return call_predicate_helper<CompLevel_full_profile>(i, b, 1, method);

   184   }

   185   return false;

   186 }

   187 

   188 // Called with the queue locked and with at least one element

   189 CompileTask* AdvancedThresholdPolicy::select_task(CompileQueue* compile_queue) {

   190   CompileTask *max_blocking_task = NULL;

   191   CompileTask *max_task = NULL;

   192   Method* max_method = NULL;

   193   jlong t = os::javaTimeMillis();

   194   // Iterate through the queue and find a method with a maximum rate.

   195   for (CompileTask* task = compile_queue->first(); task != NULL;) {

   196     CompileTask* next_task = task->next();

   197     Method* method = task->method();

   198     update_rate(t, method);

   199     if (max_task == NULL) {

   200       max_task = task;

   201       max_method = method;

   202     } else {

   203       // If a method has been stale for some time, remove it from the queue.

   204       // Blocking tasks and tasks submitted from whitebox API don't become stale

   205       if (task->can_become_stale() && is_stale(t, TieredCompileTaskTimeout, method) && !is_old(method)) {

   206         if (PrintTieredEvents) {

   207           print_event(REMOVE_FROM_QUEUE, method, method, task->osr_bci(), (CompLevel)task->comp_level());

   208         }

   209         compile_queue->remove_and_mark_stale(task);

   210         method->clear_queued_for_compilation();

   211         task = next_task;

   212         continue;

   213       }

   214 

   215       // Select a method with a higher rate

   216       if (compare_methods(method, max_method)) {

   217         max_task = task;

   218         max_method = method;

   219       }

   220     }

   221 

   222     if (task->is_blocking()) {

   223       if (max_blocking_task == NULL || compare_methods(method, max_blocking_task->method())) {

   224         max_blocking_task = task;

   225       }

   226     }

   227 

   228     task = next_task;

   229   }

   230 

   231   if (max_blocking_task != NULL) {

   232     // In blocking compilation mode, the CompileBroker will make

   233     // compilations submitted by a JVMCI compiler thread non-blocking. These

   234     // compilations should be scheduled after all blocking compilations

   235     // to service non-compiler related compilations sooner and reduce the

   236     // chance of such compilations timing out.

   237     max_task = max_blocking_task;

   238     max_method = max_task->method();

   239   }

   240 

   241   if (max_task->comp_level() == CompLevel_full_profile && TieredStopAtLevel > CompLevel_full_profile

   242       && is_method_profiled(max_method)) {

   243     max_task->set_comp_level(CompLevel_limited_profile);

   244     if (PrintTieredEvents) {

   245       print_event(UPDATE_IN_QUEUE, max_method, max_method, max_task->osr_bci(), (CompLevel)max_task->comp_level());

   246     }

   247   }

   248 

   249   return max_task;

   250 }

   251 

   252 double AdvancedThresholdPolicy::threshold_scale(CompLevel level, int feedback_k) {

   253   double queue_size = CompileBroker::queue_size(level);

   254   int comp_count = compiler_count(level);

   255   double k = queue_size / (feedback_k * comp_count) + 1;

   256 

   257   // Increase C1 compile threshold when the code cache is filled more

   258   // than specified by IncreaseFirstTierCompileThresholdAt percentage.

   259   // The main intention is to keep enough free space for C2 compiled code

   260   // to achieve peak performance if the code cache is under stress.

   261   if ((TieredStopAtLevel == CompLevel_full_optimization) && (level != CompLevel_full_optimization))  {

   262     double current_reverse_free_ratio = CodeCache::reverse_free_ratio(CodeCache::get_code_blob_type(level));

   263     if (current_reverse_free_ratio > _increase_threshold_at_ratio) {

   264       k *= exp(current_reverse_free_ratio - _increase_threshold_at_ratio);

   265     }

   266   }

   267   return k;

   268 }

   269 

   270 // Call and loop predicates determine whether a transition to a higher

   271 // compilation level should be performed (pointers to predicate functions

   272 // are passed to common()).

   273 // Tier?LoadFeedback is basically a coefficient that determines of

   274 // how many methods per compiler thread can be in the queue before

   275 // the threshold values double.

   276 bool AdvancedThresholdPolicy::loop_predicate(int i, int b, CompLevel cur_level, Method* method) {

   277   switch(cur_level) {

   278   case CompLevel_aot: {

   279     double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);

   280     return loop_predicate_helper<CompLevel_aot>(i, b, k, method);

   281   }

   282   case CompLevel_none:

   283   case CompLevel_limited_profile: {

   284     double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);

   285     return loop_predicate_helper<CompLevel_none>(i, b, k, method);

   286   }

   287   case CompLevel_full_profile: {

   288     double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);

   289     return loop_predicate_helper<CompLevel_full_profile>(i, b, k, method);

   290   }

   291   default:

   292     return true;

   293   }

   294 }

   295 

   296 bool AdvancedThresholdPolicy::call_predicate(int i, int b, CompLevel cur_level, Method* method) {

   297   switch(cur_level) {

   298   case CompLevel_aot: {

   299     double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);

   300     return call_predicate_helper<CompLevel_aot>(i, b, k, method);

   301   }

   302   case CompLevel_none:

   303   case CompLevel_limited_profile: {

   304     double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);

   305     return call_predicate_helper<CompLevel_none>(i, b, k, method);

   306   }

   307   case CompLevel_full_profile: {

   308     double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);

   309     return call_predicate_helper<CompLevel_full_profile>(i, b, k, method);

   310   }

   311   default:

   312     return true;

   313   }

   314 }

   315 

   316 // If a method is old enough and is still in the interpreter we would want to

   317 // start profiling without waiting for the compiled method to arrive.

   318 // We also take the load on compilers into the account.

   319 bool AdvancedThresholdPolicy::should_create_mdo(Method* method, CompLevel cur_level) {

   320   if (cur_level == CompLevel_none &&

   321       CompileBroker::queue_size(CompLevel_full_optimization) <=

   322       Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {

   323     int i = method->invocation_count();

   324     int b = method->backedge_count();

   325     double k = Tier0ProfilingStartPercentage / 100.0;

   326     return call_predicate_helper<CompLevel_none>(i, b, k, method) || loop_predicate_helper<CompLevel_none>(i, b, k, method);

   327   }

   328   return false;

   329 }

   330 

   331 // Inlining control: if we're compiling a profiled method with C1 and the callee

   332 // is known to have OSRed in a C2 version, don't inline it.

   333 bool AdvancedThresholdPolicy::should_not_inline(ciEnv* env, ciMethod* callee) {

   334   CompLevel comp_level = (CompLevel)env->comp_level();

   335   if (comp_level == CompLevel_full_profile ||

   336       comp_level == CompLevel_limited_profile) {

   337     return callee->highest_osr_comp_level() == CompLevel_full_optimization;

   338   }

   339   return false;

   340 }

   341 

   342 // Create MDO if necessary.

   343 void AdvancedThresholdPolicy::create_mdo(const methodHandle& mh, JavaThread* THREAD) {

   344   if (mh->is_native() ||

   345       mh->is_abstract() ||

   346       mh->is_accessor() ||

   347       mh->is_constant_getter()) {

   348     return;

   349   }

   350   if (mh->method_data() == NULL) {

   351     Method::build_interpreter_method_data(mh, CHECK_AND_CLEAR);

   352   }

   353 }

   354 

   355 

   356 /*

   357  * Method states:

   358  *   0 - interpreter (CompLevel_none)

   359  *   1 - pure C1 (CompLevel_simple)

   360  *   2 - C1 with invocation and backedge counting (CompLevel_limited_profile)

   361  *   3 - C1 with full profiling (CompLevel_full_profile)

   362  *   4 - C2 (CompLevel_full_optimization)

   363  *

   364  * Common state transition patterns:

   365  * a. 0 -> 3 -> 4.

   366  *    The most common path. But note that even in this straightforward case

   367  *    profiling can start at level 0 and finish at level 3.

   368  *

   369  * b. 0 -> 2 -> 3 -> 4.

   370  *    This case occurs when the load on C2 is deemed too high. So, instead of transitioning

   371  *    into state 3 directly and over-profiling while a method is in the C2 queue we transition to

   372  *    level 2 and wait until the load on C2 decreases. This path is disabled for OSRs.

   373  *

   374  * c. 0 -> (3->2) -> 4.

   375  *    In this case we enqueue a method for compilation at level 3, but the C1 queue is long enough

   376  *    to enable the profiling to fully occur at level 0. In this case we change the compilation level

   377  *    of the method to 2 while the request is still in-queue, because it'll allow it to run much faster

   378  *    without full profiling while c2 is compiling.

   379  *

   380  * d. 0 -> 3 -> 1 or 0 -> 2 -> 1.

   381  *    After a method was once compiled with C1 it can be identified as trivial and be compiled to

   382  *    level 1. These transition can also occur if a method can't be compiled with C2 but can with C1.

   383  *

   384  * e. 0 -> 4.

   385  *    This can happen if a method fails C1 compilation (it will still be profiled in the interpreter)

   386  *    or because of a deopt that didn't require reprofiling (compilation won't happen in this case because

   387  *    the compiled version already exists).

   388  *

   389  * Note that since state 0 can be reached from any other state via deoptimization different loops

   390  * are possible.

   391  *

   392  */

   393 

   394 // Common transition function. Given a predicate determines if a method should transition to another level.

   395 CompLevel AdvancedThresholdPolicy::common(Predicate p, Method* method, CompLevel cur_level, bool disable_feedback) {

   396   CompLevel next_level = cur_level;

   397   int i = method->invocation_count();

   398   int b = method->backedge_count();

   399 

   400   if (is_trivial(method)) {

   401     next_level = CompLevel_simple;

   402   } else {

   403     switch(cur_level) {

   404       default: break;

   405       case CompLevel_aot: {

   406       // If we were at full profile level, would we switch to full opt?

   407       if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) {

   408         next_level = CompLevel_full_optimization;

   409       } else if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=

   410                                Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&

   411                                (this->*p)(i, b, cur_level, method))) {

   412         next_level = CompLevel_full_profile;

   413       }

   414     }

   415     break;

   416     case CompLevel_none:

   417       // If we were at full profile level, would we switch to full opt?

   418       if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) {

   419         next_level = CompLevel_full_optimization;

   420       } else if ((this->*p)(i, b, cur_level, method)) {

   421 #if INCLUDE_JVMCI

   422         if (EnableJVMCI && UseJVMCICompiler) {

   423           // Since JVMCI takes a while to warm up, its queue inevitably backs up during

   424           // early VM execution. As of 2014-06-13, JVMCI's inliner assumes that the root

   425           // compilation method and all potential inlinees have mature profiles (which

   426           // includes type profiling). If it sees immature profiles, JVMCI's inliner

   427           // can perform pathologically bad (e.g., causing OutOfMemoryErrors due to

   428           // exploring/inlining too many graphs). Since a rewrite of the inliner is

   429           // in progress, we simply disable the dialing back heuristic for now and will

   430           // revisit this decision once the new inliner is completed.

   431           next_level = CompLevel_full_profile;

   432         } else

   433 #endif

   434         {

   435           // C1-generated fully profiled code is about 30% slower than the limited profile

   436           // code that has only invocation and backedge counters. The observation is that

   437           // if C2 queue is large enough we can spend too much time in the fully profiled code

   438           // while waiting for C2 to pick the method from the queue. To alleviate this problem

   439           // we introduce a feedback on the C2 queue size. If the C2 queue is sufficiently long

   440           // we choose to compile a limited profiled version and then recompile with full profiling

   441           // when the load on C2 goes down.

   442           if (!disable_feedback && CompileBroker::queue_size(CompLevel_full_optimization) >

   443               Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {

   444             next_level = CompLevel_limited_profile;

   445           } else {

   446             next_level = CompLevel_full_profile;

   447           }

   448         }

   449       }

   450       break;

   451     case CompLevel_limited_profile:

   452       if (is_method_profiled(method)) {

   453         // Special case: we got here because this method was fully profiled in the interpreter.

   454         next_level = CompLevel_full_optimization;

   455       } else {

   456         MethodData* mdo = method->method_data();

   457         if (mdo != NULL) {

   458           if (mdo->would_profile()) {

   459             if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=

   460                                      Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&

   461                                      (this->*p)(i, b, cur_level, method))) {

   462               next_level = CompLevel_full_profile;

   463             }

   464           } else {

   465             next_level = CompLevel_full_optimization;

   466           }

   467         } else {

   468           // If there is no MDO we need to profile

   469           if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=

   470                                    Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&

   471                                    (this->*p)(i, b, cur_level, method))) {

   472             next_level = CompLevel_full_profile;

   473           }

   474         }

   475       }

   476       break;

   477     case CompLevel_full_profile:

   478       {

   479         MethodData* mdo = method->method_data();

   480         if (mdo != NULL) {

   481           if (mdo->would_profile()) {

   482             int mdo_i = mdo->invocation_count_delta();

   483             int mdo_b = mdo->backedge_count_delta();

   484             if ((this->*p)(mdo_i, mdo_b, cur_level, method)) {

   485               next_level = CompLevel_full_optimization;

   486             }

   487           } else {

   488             next_level = CompLevel_full_optimization;

   489           }

   490         }

   491       }

   492       break;

   493     }

   494   }

   495   return MIN2(next_level, (CompLevel)TieredStopAtLevel);

   496 }

   497 

   498 // Determine if a method should be compiled with a normal entry point at a different level.

   499 CompLevel AdvancedThresholdPolicy::call_event(Method* method, CompLevel cur_level, JavaThread * thread) {

   500   CompLevel osr_level = MIN2((CompLevel) method->highest_osr_comp_level(),

   501                              common(&AdvancedThresholdPolicy::loop_predicate, method, cur_level, true));

   502   CompLevel next_level = common(&AdvancedThresholdPolicy::call_predicate, method, cur_level);

   503 

   504   // If OSR method level is greater than the regular method level, the levels should be

   505   // equalized by raising the regular method level in order to avoid OSRs during each

   506   // invocation of the method.

   507   if (osr_level == CompLevel_full_optimization && cur_level == CompLevel_full_profile) {

   508     MethodData* mdo = method->method_data();

   509     guarantee(mdo != NULL, "MDO should not be NULL");

   510     if (mdo->invocation_count() >= 1) {

   511       next_level = CompLevel_full_optimization;

   512     }

   513   } else {

   514     next_level = MAX2(osr_level, next_level);

   515   }

   516 #if INCLUDE_JVMCI

   517   if (UseJVMCICompiler) {

   518     next_level = JVMCIRuntime::adjust_comp_level(method, false, next_level, thread);

   519   }

   520 #endif

   521   return next_level;

   522 }

   523 

   524 // Determine if we should do an OSR compilation of a given method.

   525 CompLevel AdvancedThresholdPolicy::loop_event(Method* method, CompLevel cur_level, JavaThread * thread) {

   526   CompLevel next_level = common(&AdvancedThresholdPolicy::loop_predicate, method, cur_level, true);

   527   if (cur_level == CompLevel_none) {

   528     // If there is a live OSR method that means that we deopted to the interpreter

   529     // for the transition.

   530     CompLevel osr_level = MIN2((CompLevel)method->highest_osr_comp_level(), next_level);

   531     if (osr_level > CompLevel_none) {

   532       return osr_level;

   533     }

   534   }

   535 #if INCLUDE_JVMCI

   536   if (UseJVMCICompiler) {

   537     next_level = JVMCIRuntime::adjust_comp_level(method, true, next_level, thread);

   538   }

   539 #endif

   540   return next_level;

   541 }

   542 

   543 // Update the rate and submit compile

   544 void AdvancedThresholdPolicy::submit_compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) {

   545   int hot_count = (bci == InvocationEntryBci) ? mh->invocation_count() : mh->backedge_count();

   546   update_rate(os::javaTimeMillis(), mh());

   547   CompileBroker::compile_method(mh, bci, level, mh, hot_count, CompileTask::Reason_Tiered, thread);

   548 }

   549 

   550 bool AdvancedThresholdPolicy::maybe_switch_to_aot(const methodHandle& mh, CompLevel cur_level, CompLevel next_level, JavaThread* thread) {

   551   if (UseAOT && !delay_compilation_during_startup()) {

   552     if (cur_level == CompLevel_full_profile || cur_level == CompLevel_none) {

   553       // If the current level is full profile or interpreter and we're switching to any other level,

   554       // activate the AOT code back first so that we won't waste time overprofiling.

   555       compile(mh, InvocationEntryBci, CompLevel_aot, thread);

   556       // Fall through for JIT compilation.

   557     }

   558     if (next_level == CompLevel_limited_profile && cur_level != CompLevel_aot && mh->has_aot_code()) {

   559       // If the next level is limited profile, use the aot code (if there is any),

   560       // since it's essentially the same thing.

   561       compile(mh, InvocationEntryBci, CompLevel_aot, thread);

   562       // Not need to JIT, we're done.

   563       return true;

   564     }

   565   }

   566   return false;

   567 }

   568 

   569 

   570 // Handle the invocation event.

   571 void AdvancedThresholdPolicy::method_invocation_event(const methodHandle& mh, const methodHandle& imh,

   572                                                       CompLevel level, CompiledMethod* nm, JavaThread* thread) {

   573   if (should_create_mdo(mh(), level)) {

   574     create_mdo(mh, thread);

   575   }

   576   CompLevel next_level = call_event(mh(), level, thread);

   577   if (next_level != level) {

   578     if (maybe_switch_to_aot(mh, level, next_level, thread)) {

   579       // No JITting necessary

   580       return;

   581     }

   582     if (is_compilation_enabled() && !CompileBroker::compilation_is_in_queue(mh)) {

   583       compile(mh, InvocationEntryBci, next_level, thread);

   584     }

   585   }

   586 }

   587 

   588 // Handle the back branch event. Notice that we can compile the method

   589 // with a regular entry from here.

   590 void AdvancedThresholdPolicy::method_back_branch_event(const methodHandle& mh, const methodHandle& imh,

   591                                                        int bci, CompLevel level, CompiledMethod* nm, JavaThread* thread) {

   592   if (should_create_mdo(mh(), level)) {

   593     create_mdo(mh, thread);

   594   }

   595   // Check if MDO should be created for the inlined method

   596   if (should_create_mdo(imh(), level)) {

   597     create_mdo(imh, thread);

   598   }

   599 

   600   if (is_compilation_enabled()) {

   601     CompLevel next_osr_level = loop_event(imh(), level, thread);

   602     CompLevel max_osr_level = (CompLevel)imh->highest_osr_comp_level();

   603     // At the very least compile the OSR version

   604     if (!CompileBroker::compilation_is_in_queue(imh) && (next_osr_level != level)) {

   605       compile(imh, bci, next_osr_level, thread);

   606     }

   607 

   608     // Use loop event as an opportunity to also check if there's been

   609     // enough calls.

   610     CompLevel cur_level, next_level;

   611     if (mh() != imh()) { // If there is an enclosing method

   612       if (level == CompLevel_aot) {

   613         // Recompile the enclosing method to prevent infinite OSRs. Stay at AOT level while it's compiling.

   614         if (max_osr_level != CompLevel_none && !CompileBroker::compilation_is_in_queue(mh)) {

   615           compile(mh, InvocationEntryBci, MIN2((CompLevel)TieredStopAtLevel, CompLevel_full_profile), thread);

   616         }

   617       } else {

   618         // Current loop event level is not AOT

   619         guarantee(nm != NULL, "Should have nmethod here");

   620         cur_level = comp_level(mh());

   621         next_level = call_event(mh(), cur_level, thread);

   622 

   623         if (max_osr_level == CompLevel_full_optimization) {

   624           // The inlinee OSRed to full opt, we need to modify the enclosing method to avoid deopts

   625           bool make_not_entrant = false;

   626           if (nm->is_osr_method()) {

   627             // This is an osr method, just make it not entrant and recompile later if needed

   628             make_not_entrant = true;

   629           } else {

   630             if (next_level != CompLevel_full_optimization) {

   631               // next_level is not full opt, so we need to recompile the

   632               // enclosing method without the inlinee

   633               cur_level = CompLevel_none;

   634               make_not_entrant = true;

   635             }

   636           }

   637           if (make_not_entrant) {

   638             if (PrintTieredEvents) {

   639               int osr_bci = nm->is_osr_method() ? nm->osr_entry_bci() : InvocationEntryBci;

   640               print_event(MAKE_NOT_ENTRANT, mh(), mh(), osr_bci, level);

   641             }

   642             nm->make_not_entrant();

   643           }

   644         }

   645         // Fix up next_level if necessary to avoid deopts

   646         if (next_level == CompLevel_limited_profile && max_osr_level == CompLevel_full_profile) {

   647           next_level = CompLevel_full_profile;

   648         }

   649         if (cur_level != next_level) {

   650           if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) {

   651             compile(mh, InvocationEntryBci, next_level, thread);

   652           }

   653         }

   654       }

   655     } else {

   656       cur_level = comp_level(mh());

   657       next_level = call_event(mh(), cur_level, thread);

   658       if (next_level != cur_level) {

   659         if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) {

   660           compile(mh, InvocationEntryBci, next_level, thread);

   661         }

   662       }

   663     }

   664   }

   665 }

   666 

   667 #endif // TIERED