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     CompLevel expected_comp_level = comp_level;

   416     if (inlinee->is_not_osr_compilable(expected_comp_level)) {

   417       // It's not possble to reach the expected level so fall back to simple.

   418       expected_comp_level = CompLevel_simple;

   419     }

   420     nmethod* osr_nm = inlinee->lookup_osr_nmethod_for(bci, expected_comp_level, false);

   421     assert(osr_nm == NULL || osr_nm->comp_level() >= expected_comp_level, "lookup_osr_nmethod_for is broken");

   422     if (osr_nm != NULL) {

   423       // Perform OSR with new nmethod

   424       return osr_nm;

   425     }

   426   }

   427   return NULL;

   428 }

   429 

   430 // Check if the method can be compiled, change level if necessary

   431 void TieredThresholdPolicy::compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) {

   432   assert(level <= TieredStopAtLevel, "Invalid compilation level");

   433   if (level == CompLevel_none) {

   434     return;

   435   }

   436   if (level == CompLevel_aot) {

   437     if (mh->has_aot_code()) {

   438       if (PrintTieredEvents) {

   439         print_event(COMPILE, mh, mh, bci, level);

   440       }

   441       MutexLocker ml(Compile_lock);

   442       NoSafepointVerifier nsv;

   443       if (mh->has_aot_code() && mh->code() != mh->aot_code()) {

   444         mh->aot_code()->make_entrant();

   445         if (mh->has_compiled_code()) {

   446           mh->code()->make_not_entrant();

   447         }

   448         MutexLocker pl(CompiledMethod_lock, Mutex::_no_safepoint_check_flag);

   449         Method::set_code(mh, mh->aot_code());

   450       }

   451     }

   452     return;

   453   }

   454 

   455   // Check if the method can be compiled. If it cannot be compiled with C1, continue profiling

   456   // in the interpreter and then compile with C2 (the transition function will request that,

   457   // see common() ). If the method cannot be compiled with C2 but still can with C1, compile it with

   458   // pure C1.

   459   if ((bci == InvocationEntryBci && !can_be_compiled(mh, level))) {

   460     if (level == CompLevel_full_optimization && can_be_compiled(mh, CompLevel_simple)) {

   461       compile(mh, bci, CompLevel_simple, thread);

   462     }

   463     return;

   464   }

   465   if ((bci != InvocationEntryBci && !can_be_osr_compiled(mh, level))) {

   466     if (level == CompLevel_full_optimization && can_be_osr_compiled(mh, CompLevel_simple)) {

   467       nmethod* osr_nm = mh->lookup_osr_nmethod_for(bci, CompLevel_simple, false);

   468       if (osr_nm != NULL && osr_nm->comp_level() > CompLevel_simple) {

   469         // Invalidate the existing OSR nmethod so that a compile at CompLevel_simple is permitted.

   470         osr_nm->make_not_entrant();

   471       }

   472       compile(mh, bci, CompLevel_simple, thread);

   473     }

   474     return;

   475   }

   476   if (bci != InvocationEntryBci && mh->is_not_osr_compilable(level)) {

   477     return;

   478   }

   479   if (!CompileBroker::compilation_is_in_queue(mh)) {

   480     if (PrintTieredEvents) {

   481       print_event(COMPILE, mh, mh, bci, level);

   482     }

   483     submit_compile(mh, bci, level, thread);

   484   }

   485 }

   486 

   487 // Update the rate and submit compile

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

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

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

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

   492 }

   493 

   494 // Print an event.

   495 void TieredThresholdPolicy::print_specific(EventType type, const methodHandle& mh, const methodHandle& imh,

   496                                              int bci, CompLevel level) {

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

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

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

   500 

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

   502                                threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback));

   503 

   504 }

   505 

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

   507 void TieredThresholdPolicy::update_rate(jlong t, Method* m) {

   508   // Skip update if counters are absent.

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

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

   511 

   512   if (is_old(m)) {

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

   514     // so we can just zero the rate.

   515     m->set_rate(0);

   516     return;

   517   }

   518 

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

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

   521   jlong delta_s = t - SafepointTracing::end_of_last_safepoint_epoch_ms();

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

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

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

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

   526 

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

   528   if (delta_s >= TieredRateUpdateMinTime) {

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

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

   531       m->set_prev_time(t);

   532       m->set_prev_event_count(event_count);

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

   534     } else {

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

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

   537         m->set_rate(0);

   538       }

   539     }

   540   }

   541 }

   542 

   543 // Check if this method has been stale for a given number of milliseconds.

   544 // See select_task().

   545 bool TieredThresholdPolicy::is_stale(jlong t, jlong timeout, Method* m) {

   546   jlong delta_s = t - SafepointTracing::end_of_last_safepoint_epoch_ms();

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

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

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

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

   551     // Return true if there were no events.

   552     return delta_e == 0;

   553   }

   554   return false;

   555 }

   556 

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

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

   559 bool TieredThresholdPolicy::is_old(Method* method) {

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

   561 }

   562 

   563 double TieredThresholdPolicy::weight(Method* method) {

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

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

   566 }

   567 

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

   569 bool TieredThresholdPolicy::compare_methods(Method* x, Method* y) {

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

   571     // recompilation after deopt

   572     return true;

   573   } else

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

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

   576         return true;

   577       }

   578     }

   579   return false;

   580 }

   581 

   582 // Is method profiled enough?

   583 bool TieredThresholdPolicy::is_method_profiled(Method* method) {

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

   585   if (mdo != NULL) {

   586     int i = mdo->invocation_count_delta();

   587     int b = mdo->backedge_count_delta();

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

   589   }

   590   return false;

   591 }

   592 

   593 double TieredThresholdPolicy::threshold_scale(CompLevel level, int feedback_k) {

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

   595   int comp_count = compiler_count(level);

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

   597 

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

   599   // than specified by IncreaseFirstTierCompileThresholdAt percentage.

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

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

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

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

   604     if (current_reverse_free_ratio > _increase_threshold_at_ratio) {

   605       k *= exp(current_reverse_free_ratio - _increase_threshold_at_ratio);

   606     }

   607   }

   608   return k;

   609 }

   610 

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

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

   613 // are passed to common()).

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

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

   616 // the threshold values double.

   617 bool TieredThresholdPolicy::loop_predicate(int i, int b, CompLevel cur_level, Method* method) {

   618   switch(cur_level) {

   619   case CompLevel_aot: {

   620     double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);

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

   622   }

   623   case CompLevel_none:

   624   case CompLevel_limited_profile: {

   625     double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);

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

   627   }

   628   case CompLevel_full_profile: {

   629     double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);

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

   631   }

   632   default:

   633     return true;

   634   }

   635 }

   636 

   637 bool TieredThresholdPolicy::call_predicate(int i, int b, CompLevel cur_level, Method* method) {

   638   switch(cur_level) {

   639   case CompLevel_aot: {

   640     double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);

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

   642   }

   643   case CompLevel_none:

   644   case CompLevel_limited_profile: {

   645     double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);

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

   647   }

   648   case CompLevel_full_profile: {

   649     double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);

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

   651   }

   652   default:

   653     return true;

   654   }

   655 }

   656 

   657 // Determine is a method is mature.

   658 bool TieredThresholdPolicy::is_mature(Method* method) {

   659   if (should_compile_at_level_simple(method)) return true;

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

   661   if (mdo != NULL) {

   662     int i = mdo->invocation_count();

   663     int b = mdo->backedge_count();

   664     double k = ProfileMaturityPercentage / 100.0;

   665     return call_predicate_helper<CompLevel_full_profile>(i, b, k, method) ||

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

   667   }

   668   return false;

   669 }

   670 

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

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

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

   674 bool TieredThresholdPolicy::should_create_mdo(Method* method, CompLevel cur_level) {

   675   if (cur_level == CompLevel_none &&

   676       CompileBroker::queue_size(CompLevel_full_optimization) <=

   677       Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {

   678     int i = method->invocation_count();

   679     int b = method->backedge_count();

   680     double k = Tier0ProfilingStartPercentage / 100.0;

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

   682   }

   683   return false;

   684 }

   685 

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

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

   688 bool TieredThresholdPolicy::should_not_inline(ciEnv* env, ciMethod* callee) {

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

   690   if (comp_level == CompLevel_full_profile ||

   691       comp_level == CompLevel_limited_profile) {

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

   693   }

   694   return false;

   695 }

   696 

   697 // Create MDO if necessary.

   698 void TieredThresholdPolicy::create_mdo(const methodHandle& mh, JavaThread* THREAD) {

   699   if (mh->is_native() ||

   700       mh->is_abstract() ||

   701       mh->is_accessor() ||

   702       mh->is_constant_getter()) {

   703     return;

   704   }

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

   706     Method::build_interpreter_method_data(mh, CHECK_AND_CLEAR);

   707   }

   708 }

   709 

   710 

   711 /*

   712  * Method states:

   713  *   0 - interpreter (CompLevel_none)

   714  *   1 - pure C1 (CompLevel_simple)

   715  *   2 - C1 with invocation and backedge counting (CompLevel_limited_profile)

   716  *   3 - C1 with full profiling (CompLevel_full_profile)

   717  *   4 - C2 (CompLevel_full_optimization)

   718  *

   719  * Common state transition patterns:

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

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

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

   723  *

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

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

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

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

   728  *

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

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

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

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

   733  *    without full profiling while c2 is compiling.

   734  *

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

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

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

   738  *

   739  * e. 0 -> 4.

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

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

   742  *    the compiled version already exists).

   743  *

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

   745  * are possible.

   746  *

   747  */

   748 

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

   750 CompLevel TieredThresholdPolicy::common(Predicate p, Method* method, CompLevel cur_level, bool disable_feedback) {

   751   CompLevel next_level = cur_level;

   752   int i = method->invocation_count();

   753   int b = method->backedge_count();

   754 

   755   if (should_compile_at_level_simple(method)) {

   756     next_level = CompLevel_simple;

   757   } else {

   758     switch(cur_level) {

   759       default: break;

   760       case CompLevel_aot: {

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

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

   763         next_level = CompLevel_full_optimization;

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

   765                                Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&

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

   767         next_level = CompLevel_full_profile;

   768       }

   769     }

   770     break;

   771     case CompLevel_none:

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

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

   774         next_level = CompLevel_full_optimization;

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

   776 #if INCLUDE_JVMCI

   777         if (EnableJVMCI && UseJVMCICompiler) {

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

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

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

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

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

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

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

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

   786           next_level = CompLevel_full_profile;

   787         } else

   788 #endif

   789         {

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

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

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

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

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

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

   796           // when the load on C2 goes down.

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

   798               Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {

   799             next_level = CompLevel_limited_profile;

   800           } else {

   801             next_level = CompLevel_full_profile;

   802           }

   803         }

   804       }

   805       break;

   806     case CompLevel_limited_profile:

   807       if (is_method_profiled(method)) {

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

   809         next_level = CompLevel_full_optimization;

   810       } else {

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

   812         if (mdo != NULL) {

   813           if (mdo->would_profile()) {

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

   815                                      Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&

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

   817               next_level = CompLevel_full_profile;

   818             }

   819           } else {

   820             next_level = CompLevel_full_optimization;

   821           }

   822         } else {

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

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

   825                                    Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&

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

   827             next_level = CompLevel_full_profile;

   828           }

   829         }

   830       }

   831       break;

   832     case CompLevel_full_profile:

   833       {

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

   835         if (mdo != NULL) {

   836           if (mdo->would_profile()) {

   837             int mdo_i = mdo->invocation_count_delta();

   838             int mdo_b = mdo->backedge_count_delta();

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

   840               next_level = CompLevel_full_optimization;

   841             }

   842           } else {

   843             next_level = CompLevel_full_optimization;

   844           }

   845         }

   846       }

   847       break;

   848     }

   849   }

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

   851 }

   852 

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

   854 CompLevel TieredThresholdPolicy::call_event(Method* method, CompLevel cur_level, JavaThread * thread) {

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

   856                              common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true));

   857   CompLevel next_level = common(&TieredThresholdPolicy::call_predicate, method, cur_level);

   858 

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

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

   861   // invocation of the method.

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

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

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

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

   866       next_level = CompLevel_full_optimization;

   867     }

   868   } else {

   869     next_level = MAX2(osr_level, next_level);

   870   }

   871   return next_level;

   872 }

   873 

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

   875 CompLevel TieredThresholdPolicy::loop_event(Method* method, CompLevel cur_level, JavaThread* thread) {

   876   CompLevel next_level = common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true);

   877   if (cur_level == CompLevel_none) {

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

   879     // for the transition.

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

   881     if (osr_level > CompLevel_none) {

   882       return osr_level;

   883     }

   884   }

   885   return next_level;

   886 }

   887 

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

   889   if (UseAOT) {

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

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

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

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

   894       // Fall through for JIT compilation.

   895     }

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

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

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

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

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

   901       return true;

   902     }

   903   }

   904   return false;

   905 }

   906 

   907 

   908 // Handle the invocation event.

   909 void TieredThresholdPolicy::method_invocation_event(const methodHandle& mh, const methodHandle& imh,

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

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

   912     create_mdo(mh, thread);

   913   }

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

   915   if (next_level != level) {

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

   917       // No JITting necessary

   918       return;

   919     }

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

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

   922     }

   923   }

   924 }

   925 

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

   927 // with a regular entry from here.

   928 void TieredThresholdPolicy::method_back_branch_event(const methodHandle& mh, const methodHandle& imh,

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

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

   931     create_mdo(mh, thread);

   932   }

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

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

   935     create_mdo(imh, thread);

   936   }

   937 

   938   if (is_compilation_enabled()) {

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

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

   941     // At the very least compile the OSR version

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

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

   944     }

   945 

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

   947     // enough calls.

   948     CompLevel cur_level, next_level;

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

   950       if (level == CompLevel_aot) {

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

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

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

   954         }

   955       } else {

   956         // Current loop event level is not AOT

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

   958         cur_level = comp_level(mh());

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

   960 

   961         if (max_osr_level == CompLevel_full_optimization) {

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

   963           bool make_not_entrant = false;

   964           if (nm->is_osr_method()) {

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

   966             make_not_entrant = true;

   967           } else {

   968             if (next_level != CompLevel_full_optimization) {

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

   970               // enclosing method without the inlinee

   971               cur_level = CompLevel_none;

   972               make_not_entrant = true;

   973             }

   974           }

   975           if (make_not_entrant) {

   976             if (PrintTieredEvents) {

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

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

   979             }

   980             nm->make_not_entrant();

   981           }

   982         }

   983         // Fix up next_level if necessary to avoid deopts

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

   985           next_level = CompLevel_full_profile;

   986         }

   987         if (cur_level != next_level) {

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

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

   990           }

   991         }

   992       }

   993     } else {

   994       cur_level = comp_level(mh());

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

   996       if (next_level != cur_level) {

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

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

   999         }

  1000       }

  1001     }

  1002   }

  1003 }

  1004 

  1005 #endif