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 Method::set_code(mh, mh->aot_code()); 449 } 450 } 451 return; 452 } 453 454 // Check if the method can be compiled. If it cannot be compiled with C1, continue profiling 455 // in the interpreter and then compile with C2 (the transition function will request that, 456 // see common() ). If the method cannot be compiled with C2 but still can with C1, compile it with 457 // pure C1. 458 if ((bci == InvocationEntryBci && !can_be_compiled(mh, level))) { 459 if (level == CompLevel_full_optimization && can_be_compiled(mh, CompLevel_simple)) { 460 compile(mh, bci, CompLevel_simple, thread); 461 } 462 return; 463 } 464 if ((bci != InvocationEntryBci && !can_be_osr_compiled(mh, level))) { 465 if (level == CompLevel_full_optimization && can_be_osr_compiled(mh, CompLevel_simple)) { 466 nmethod* osr_nm = mh->lookup_osr_nmethod_for(bci, CompLevel_simple, false); 467 if (osr_nm != NULL && osr_nm->comp_level() > CompLevel_simple) { 468 // Invalidate the existing OSR nmethod so that a compile at CompLevel_simple is permitted. 469 osr_nm->make_not_entrant(); 470 } 471 compile(mh, bci, CompLevel_simple, thread); 472 } 473 return; 474 } 475 if (bci != InvocationEntryBci && mh->is_not_osr_compilable(level)) { 476 return; 477 } 478 if (!CompileBroker::compilation_is_in_queue(mh)) { 479 if (PrintTieredEvents) { 480 print_event(COMPILE, mh, mh, bci, level); 481 } 482 submit_compile(mh, bci, level, thread); 483 } 484 } 485 486 // Update the rate and submit compile 487 void TieredThresholdPolicy::submit_compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) { 488 int hot_count = (bci == InvocationEntryBci) ? mh->invocation_count() : mh->backedge_count(); 489 update_rate(os::javaTimeMillis(), mh()); 490 CompileBroker::compile_method(mh, bci, level, mh, hot_count, CompileTask::Reason_Tiered, thread); 491 } 492 493 // Print an event. 494 void TieredThresholdPolicy::print_specific(EventType type, const methodHandle& mh, const methodHandle& imh, 495 int bci, CompLevel level) { 496 tty->print(" rate="); 497 if (mh->prev_time() == 0) tty->print("n/a"); 498 else tty->print("%f", mh->rate()); 499 500 tty->print(" k=%.2lf,%.2lf", threshold_scale(CompLevel_full_profile, Tier3LoadFeedback), 501 threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback)); 502 503 } 504 505 // update_rate() is called from select_task() while holding a compile queue lock. 506 void TieredThresholdPolicy::update_rate(jlong t, Method* m) { 507 // Skip update if counters are absent. 508 // Can't allocate them since we are holding compile queue lock. 509 if (m->method_counters() == NULL) return; 510 511 if (is_old(m)) { 512 // We don't remove old methods from the queue, 513 // so we can just zero the rate. 514 m->set_rate(0); 515 return; 516 } 517 518 // We don't update the rate if we've just came out of a safepoint. 519 // delta_s is the time since last safepoint in milliseconds. 520 jlong delta_s = t - SafepointTracing::end_of_last_safepoint_epoch_ms(); 521 jlong delta_t = t - (m->prev_time() != 0 ? m->prev_time() : start_time()); // milliseconds since the last measurement 522 // How many events were there since the last time? 523 int event_count = m->invocation_count() + m->backedge_count(); 524 int delta_e = event_count - m->prev_event_count(); 525 526 // We should be running for at least 1ms. 527 if (delta_s >= TieredRateUpdateMinTime) { 528 // And we must've taken the previous point at least 1ms before. 529 if (delta_t >= TieredRateUpdateMinTime && delta_e > 0) { 530 m->set_prev_time(t); 531 m->set_prev_event_count(event_count); 532 m->set_rate((float)delta_e / (float)delta_t); // Rate is events per millisecond 533 } else { 534 if (delta_t > TieredRateUpdateMaxTime && delta_e == 0) { 535 // If nothing happened for 25ms, zero the rate. Don't modify prev values. 536 m->set_rate(0); 537 } 538 } 539 } 540 } 541 542 // Check if this method has been stale for a given number of milliseconds. 543 // See select_task(). 544 bool TieredThresholdPolicy::is_stale(jlong t, jlong timeout, Method* m) { 545 jlong delta_s = t - SafepointTracing::end_of_last_safepoint_epoch_ms(); 546 jlong delta_t = t - m->prev_time(); 547 if (delta_t > timeout && delta_s > timeout) { 548 int event_count = m->invocation_count() + m->backedge_count(); 549 int delta_e = event_count - m->prev_event_count(); 550 // Return true if there were no events. 551 return delta_e == 0; 552 } 553 return false; 554 } 555 556 // We don't remove old methods from the compile queue even if they have 557 // very low activity. See select_task(). 558 bool TieredThresholdPolicy::is_old(Method* method) { 559 return method->invocation_count() > 50000 || method->backedge_count() > 500000; 560 } 561 562 double TieredThresholdPolicy::weight(Method* method) { 563 return (double)(method->rate() + 1) * 564 (method->invocation_count() + 1) * (method->backedge_count() + 1); 565 } 566 567 // Apply heuristics and return true if x should be compiled before y 568 bool TieredThresholdPolicy::compare_methods(Method* x, Method* y) { 569 if (x->highest_comp_level() > y->highest_comp_level()) { 570 // recompilation after deopt 571 return true; 572 } else 573 if (x->highest_comp_level() == y->highest_comp_level()) { 574 if (weight(x) > weight(y)) { 575 return true; 576 } 577 } 578 return false; 579 } 580 581 // Is method profiled enough? 582 bool TieredThresholdPolicy::is_method_profiled(Method* method) { 583 MethodData* mdo = method->method_data(); 584 if (mdo != NULL) { 585 int i = mdo->invocation_count_delta(); 586 int b = mdo->backedge_count_delta(); 587 return call_predicate_helper<CompLevel_full_profile>(i, b, 1, method); 588 } 589 return false; 590 } 591 592 double TieredThresholdPolicy::threshold_scale(CompLevel level, int feedback_k) { 593 double queue_size = CompileBroker::queue_size(level); 594 int comp_count = compiler_count(level); 595 double k = queue_size / (feedback_k * comp_count) + 1; 596 597 // Increase C1 compile threshold when the code cache is filled more 598 // than specified by IncreaseFirstTierCompileThresholdAt percentage. 599 // The main intention is to keep enough free space for C2 compiled code 600 // to achieve peak performance if the code cache is under stress. 601 if ((TieredStopAtLevel == CompLevel_full_optimization) && (level != CompLevel_full_optimization)) { 602 double current_reverse_free_ratio = CodeCache::reverse_free_ratio(CodeCache::get_code_blob_type(level)); 603 if (current_reverse_free_ratio > _increase_threshold_at_ratio) { 604 k *= exp(current_reverse_free_ratio - _increase_threshold_at_ratio); 605 } 606 } 607 return k; 608 } 609 610 // Call and loop predicates determine whether a transition to a higher 611 // compilation level should be performed (pointers to predicate functions 612 // are passed to common()). 613 // Tier?LoadFeedback is basically a coefficient that determines of 614 // how many methods per compiler thread can be in the queue before 615 // the threshold values double. 616 bool TieredThresholdPolicy::loop_predicate(int i, int b, CompLevel cur_level, Method* method) { 617 switch(cur_level) { 618 case CompLevel_aot: { 619 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback); 620 return loop_predicate_helper<CompLevel_aot>(i, b, k, method); 621 } 622 case CompLevel_none: 623 case CompLevel_limited_profile: { 624 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback); 625 return loop_predicate_helper<CompLevel_none>(i, b, k, method); 626 } 627 case CompLevel_full_profile: { 628 double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback); 629 return loop_predicate_helper<CompLevel_full_profile>(i, b, k, method); 630 } 631 default: 632 return true; 633 } 634 } 635 636 bool TieredThresholdPolicy::call_predicate(int i, int b, CompLevel cur_level, Method* method) { 637 switch(cur_level) { 638 case CompLevel_aot: { 639 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback); 640 return call_predicate_helper<CompLevel_aot>(i, b, k, method); 641 } 642 case CompLevel_none: 643 case CompLevel_limited_profile: { 644 double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback); 645 return call_predicate_helper<CompLevel_none>(i, b, k, method); 646 } 647 case CompLevel_full_profile: { 648 double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback); 649 return call_predicate_helper<CompLevel_full_profile>(i, b, k, method); 650 } 651 default: 652 return true; 653 } 654 } 655 656 // Determine is a method is mature. 657 bool TieredThresholdPolicy::is_mature(Method* method) { 658 if (should_compile_at_level_simple(method)) return true; 659 MethodData* mdo = method->method_data(); 660 if (mdo != NULL) { 661 int i = mdo->invocation_count(); 662 int b = mdo->backedge_count(); 663 double k = ProfileMaturityPercentage / 100.0; 664 return call_predicate_helper<CompLevel_full_profile>(i, b, k, method) || 665 loop_predicate_helper<CompLevel_full_profile>(i, b, k, method); 666 } 667 return false; 668 } 669 670 // If a method is old enough and is still in the interpreter we would want to 671 // start profiling without waiting for the compiled method to arrive. 672 // We also take the load on compilers into the account. 673 bool TieredThresholdPolicy::should_create_mdo(Method* method, CompLevel cur_level) { 674 if (cur_level == CompLevel_none && 675 CompileBroker::queue_size(CompLevel_full_optimization) <= 676 Tier3DelayOn * compiler_count(CompLevel_full_optimization)) { 677 int i = method->invocation_count(); 678 int b = method->backedge_count(); 679 double k = Tier0ProfilingStartPercentage / 100.0; 680 return call_predicate_helper<CompLevel_none>(i, b, k, method) || loop_predicate_helper<CompLevel_none>(i, b, k, method); 681 } 682 return false; 683 } 684 685 // Inlining control: if we're compiling a profiled method with C1 and the callee 686 // is known to have OSRed in a C2 version, don't inline it. 687 bool TieredThresholdPolicy::should_not_inline(ciEnv* env, ciMethod* callee) { 688 CompLevel comp_level = (CompLevel)env->comp_level(); 689 if (comp_level == CompLevel_full_profile || 690 comp_level == CompLevel_limited_profile) { 691 return callee->highest_osr_comp_level() == CompLevel_full_optimization; 692 } 693 return false; 694 } 695 696 // Create MDO if necessary. 697 void TieredThresholdPolicy::create_mdo(const methodHandle& mh, JavaThread* THREAD) { 698 if (mh->is_native() || 699 mh->is_abstract() || 700 mh->is_accessor() || 701 mh->is_constant_getter()) { 702 return; 703 } 704 if (mh->method_data() == NULL) { 705 Method::build_interpreter_method_data(mh, CHECK_AND_CLEAR); 706 } 707 } 708 709 710 /* 711 * Method states: 712 * 0 - interpreter (CompLevel_none) 713 * 1 - pure C1 (CompLevel_simple) 714 * 2 - C1 with invocation and backedge counting (CompLevel_limited_profile) 715 * 3 - C1 with full profiling (CompLevel_full_profile) 716 * 4 - C2 (CompLevel_full_optimization) 717 * 718 * Common state transition patterns: 719 * a. 0 -> 3 -> 4. 720 * The most common path. But note that even in this straightforward case 721 * profiling can start at level 0 and finish at level 3. 722 * 723 * b. 0 -> 2 -> 3 -> 4. 724 * This case occurs when the load on C2 is deemed too high. So, instead of transitioning 725 * into state 3 directly and over-profiling while a method is in the C2 queue we transition to 726 * level 2 and wait until the load on C2 decreases. This path is disabled for OSRs. 727 * 728 * c. 0 -> (3->2) -> 4. 729 * In this case we enqueue a method for compilation at level 3, but the C1 queue is long enough 730 * to enable the profiling to fully occur at level 0. In this case we change the compilation level 731 * of the method to 2 while the request is still in-queue, because it'll allow it to run much faster 732 * without full profiling while c2 is compiling. 733 * 734 * d. 0 -> 3 -> 1 or 0 -> 2 -> 1. 735 * After a method was once compiled with C1 it can be identified as trivial and be compiled to 736 * level 1. These transition can also occur if a method can't be compiled with C2 but can with C1. 737 * 738 * e. 0 -> 4. 739 * This can happen if a method fails C1 compilation (it will still be profiled in the interpreter) 740 * or because of a deopt that didn't require reprofiling (compilation won't happen in this case because 741 * the compiled version already exists). 742 * 743 * Note that since state 0 can be reached from any other state via deoptimization different loops 744 * are possible. 745 * 746 */ 747 748 // Common transition function. Given a predicate determines if a method should transition to another level. 749 CompLevel TieredThresholdPolicy::common(Predicate p, Method* method, CompLevel cur_level, bool disable_feedback) { 750 CompLevel next_level = cur_level; 751 int i = method->invocation_count(); 752 int b = method->backedge_count(); 753 754 if (should_compile_at_level_simple(method)) { 755 next_level = CompLevel_simple; 756 } else { 757 switch(cur_level) { 758 default: break; 759 case CompLevel_aot: { 760 // If we were at full profile level, would we switch to full opt? 761 if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) { 762 next_level = CompLevel_full_optimization; 763 } else if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <= 764 Tier3DelayOff * compiler_count(CompLevel_full_optimization) && 765 (this->*p)(i, b, cur_level, method))) { 766 next_level = CompLevel_full_profile; 767 } 768 } 769 break; 770 case CompLevel_none: 771 // If we were at full profile level, would we switch to full opt? 772 if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) { 773 next_level = CompLevel_full_optimization; 774 } else if ((this->*p)(i, b, cur_level, method)) { 775 #if INCLUDE_JVMCI 776 if (EnableJVMCI && UseJVMCICompiler) { 777 // Since JVMCI takes a while to warm up, its queue inevitably backs up during 778 // early VM execution. As of 2014-06-13, JVMCI's inliner assumes that the root 779 // compilation method and all potential inlinees have mature profiles (which 780 // includes type profiling). If it sees immature profiles, JVMCI's inliner 781 // can perform pathologically bad (e.g., causing OutOfMemoryErrors due to 782 // exploring/inlining too many graphs). Since a rewrite of the inliner is 783 // in progress, we simply disable the dialing back heuristic for now and will 784 // revisit this decision once the new inliner is completed. 785 next_level = CompLevel_full_profile; 786 } else 787 #endif 788 { 789 // C1-generated fully profiled code is about 30% slower than the limited profile 790 // code that has only invocation and backedge counters. The observation is that 791 // if C2 queue is large enough we can spend too much time in the fully profiled code 792 // while waiting for C2 to pick the method from the queue. To alleviate this problem 793 // we introduce a feedback on the C2 queue size. If the C2 queue is sufficiently long 794 // we choose to compile a limited profiled version and then recompile with full profiling 795 // when the load on C2 goes down. 796 if (!disable_feedback && CompileBroker::queue_size(CompLevel_full_optimization) > 797 Tier3DelayOn * compiler_count(CompLevel_full_optimization)) { 798 next_level = CompLevel_limited_profile; 799 } else { 800 next_level = CompLevel_full_profile; 801 } 802 } 803 } 804 break; 805 case CompLevel_limited_profile: 806 if (is_method_profiled(method)) { 807 // Special case: we got here because this method was fully profiled in the interpreter. 808 next_level = CompLevel_full_optimization; 809 } else { 810 MethodData* mdo = method->method_data(); 811 if (mdo != NULL) { 812 if (mdo->would_profile()) { 813 if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <= 814 Tier3DelayOff * compiler_count(CompLevel_full_optimization) && 815 (this->*p)(i, b, cur_level, method))) { 816 next_level = CompLevel_full_profile; 817 } 818 } else { 819 next_level = CompLevel_full_optimization; 820 } 821 } else { 822 // If there is no MDO we need to profile 823 if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <= 824 Tier3DelayOff * compiler_count(CompLevel_full_optimization) && 825 (this->*p)(i, b, cur_level, method))) { 826 next_level = CompLevel_full_profile; 827 } 828 } 829 } 830 break; 831 case CompLevel_full_profile: 832 { 833 MethodData* mdo = method->method_data(); 834 if (mdo != NULL) { 835 if (mdo->would_profile()) { 836 int mdo_i = mdo->invocation_count_delta(); 837 int mdo_b = mdo->backedge_count_delta(); 838 if ((this->*p)(mdo_i, mdo_b, cur_level, method)) { 839 next_level = CompLevel_full_optimization; 840 } 841 } else { 842 next_level = CompLevel_full_optimization; 843 } 844 } 845 } 846 break; 847 } 848 } 849 return MIN2(next_level, (CompLevel)TieredStopAtLevel); 850 } 851 852 // Determine if a method should be compiled with a normal entry point at a different level. 853 CompLevel TieredThresholdPolicy::call_event(Method* method, CompLevel cur_level, JavaThread * thread) { 854 CompLevel osr_level = MIN2((CompLevel) method->highest_osr_comp_level(), 855 common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true)); 856 CompLevel next_level = common(&TieredThresholdPolicy::call_predicate, method, cur_level); 857 858 // If OSR method level is greater than the regular method level, the levels should be 859 // equalized by raising the regular method level in order to avoid OSRs during each 860 // invocation of the method. 861 if (osr_level == CompLevel_full_optimization && cur_level == CompLevel_full_profile) { 862 MethodData* mdo = method->method_data(); 863 guarantee(mdo != NULL, "MDO should not be NULL"); 864 if (mdo->invocation_count() >= 1) { 865 next_level = CompLevel_full_optimization; 866 } 867 } else { 868 next_level = MAX2(osr_level, next_level); 869 } 870 return next_level; 871 } 872 873 // Determine if we should do an OSR compilation of a given method. 874 CompLevel TieredThresholdPolicy::loop_event(Method* method, CompLevel cur_level, JavaThread* thread) { 875 CompLevel next_level = common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true); 876 if (cur_level == CompLevel_none) { 877 // If there is a live OSR method that means that we deopted to the interpreter 878 // for the transition. 879 CompLevel osr_level = MIN2((CompLevel)method->highest_osr_comp_level(), next_level); 880 if (osr_level > CompLevel_none) { 881 return osr_level; 882 } 883 } 884 return next_level; 885 } 886 887 bool TieredThresholdPolicy::maybe_switch_to_aot(const methodHandle& mh, CompLevel cur_level, CompLevel next_level, JavaThread* thread) { 888 if (UseAOT) { 889 if (cur_level == CompLevel_full_profile || cur_level == CompLevel_none) { 890 // If the current level is full profile or interpreter and we're switching to any other level, 891 // activate the AOT code back first so that we won't waste time overprofiling. 892 compile(mh, InvocationEntryBci, CompLevel_aot, thread); 893 // Fall through for JIT compilation. 894 } 895 if (next_level == CompLevel_limited_profile && cur_level != CompLevel_aot && mh->has_aot_code()) { 896 // If the next level is limited profile, use the aot code (if there is any), 897 // since it's essentially the same thing. 898 compile(mh, InvocationEntryBci, CompLevel_aot, thread); 899 // Not need to JIT, we're done. 900 return true; 901 } 902 } 903 return false; 904 } 905 906 907 // Handle the invocation event. 908 void TieredThresholdPolicy::method_invocation_event(const methodHandle& mh, const methodHandle& imh, 909 CompLevel level, CompiledMethod* nm, JavaThread* thread) { 910 if (should_create_mdo(mh(), level)) { 911 create_mdo(mh, thread); 912 } 913 CompLevel next_level = call_event(mh(), level, thread); 914 if (next_level != level) { 915 if (maybe_switch_to_aot(mh, level, next_level, thread)) { 916 // No JITting necessary 917 return; 918 } 919 if (is_compilation_enabled() && !CompileBroker::compilation_is_in_queue(mh)) { 920 compile(mh, InvocationEntryBci, next_level, thread); 921 } 922 } 923 } 924 925 // Handle the back branch event. Notice that we can compile the method 926 // with a regular entry from here. 927 void TieredThresholdPolicy::method_back_branch_event(const methodHandle& mh, const methodHandle& imh, 928 int bci, CompLevel level, CompiledMethod* nm, JavaThread* thread) { 929 if (should_create_mdo(mh(), level)) { 930 create_mdo(mh, thread); 931 } 932 // Check if MDO should be created for the inlined method 933 if (should_create_mdo(imh(), level)) { 934 create_mdo(imh, thread); 935 } 936 937 if (is_compilation_enabled()) { 938 CompLevel next_osr_level = loop_event(imh(), level, thread); 939 CompLevel max_osr_level = (CompLevel)imh->highest_osr_comp_level(); 940 // At the very least compile the OSR version 941 if (!CompileBroker::compilation_is_in_queue(imh) && (next_osr_level != level)) { 942 compile(imh, bci, next_osr_level, thread); 943 } 944 945 // Use loop event as an opportunity to also check if there's been 946 // enough calls. 947 CompLevel cur_level, next_level; 948 if (mh() != imh()) { // If there is an enclosing method 949 if (level == CompLevel_aot) { 950 // Recompile the enclosing method to prevent infinite OSRs. Stay at AOT level while it's compiling. 951 if (max_osr_level != CompLevel_none && !CompileBroker::compilation_is_in_queue(mh)) { 952 compile(mh, InvocationEntryBci, MIN2((CompLevel)TieredStopAtLevel, CompLevel_full_profile), thread); 953 } 954 } else { 955 // Current loop event level is not AOT 956 guarantee(nm != NULL, "Should have nmethod here"); 957 cur_level = comp_level(mh()); 958 next_level = call_event(mh(), cur_level, thread); 959 960 if (max_osr_level == CompLevel_full_optimization) { 961 // The inlinee OSRed to full opt, we need to modify the enclosing method to avoid deopts 962 bool make_not_entrant = false; 963 if (nm->is_osr_method()) { 964 // This is an osr method, just make it not entrant and recompile later if needed 965 make_not_entrant = true; 966 } else { 967 if (next_level != CompLevel_full_optimization) { 968 // next_level is not full opt, so we need to recompile the 969 // enclosing method without the inlinee 970 cur_level = CompLevel_none; 971 make_not_entrant = true; 972 } 973 } 974 if (make_not_entrant) { 975 if (PrintTieredEvents) { 976 int osr_bci = nm->is_osr_method() ? nm->osr_entry_bci() : InvocationEntryBci; 977 print_event(MAKE_NOT_ENTRANT, mh(), mh(), osr_bci, level); 978 } 979 nm->make_not_entrant(); 980 } 981 } 982 // Fix up next_level if necessary to avoid deopts 983 if (next_level == CompLevel_limited_profile && max_osr_level == CompLevel_full_profile) { 984 next_level = CompLevel_full_profile; 985 } 986 if (cur_level != next_level) { 987 if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) { 988 compile(mh, InvocationEntryBci, next_level, thread); 989 } 990 } 991 } 992 } else { 993 cur_level = comp_level(mh()); 994 next_level = call_event(mh(), cur_level, thread); 995 if (next_level != cur_level) { 996 if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) { 997 compile(mh, InvocationEntryBci, next_level, thread); 998 } 999 } 1000 } 1001 } 1002 } 1003 1004 #endif