/* * Copyright (c) 2010, 2020, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "compiler/compileBroker.hpp" #include "compiler/compilerOracle.hpp" #include "compiler/tieredThresholdPolicy.hpp" #include "memory/resourceArea.hpp" #include "runtime/arguments.hpp" #include "runtime/frame.inline.hpp" #include "runtime/handles.inline.hpp" #include "runtime/safepoint.hpp" #include "runtime/safepointVerifiers.hpp" #include "code/scopeDesc.hpp" #include "oops/method.inline.hpp" #if INCLUDE_JVMCI #include "jvmci/jvmci.hpp" #endif #ifdef TIERED #include "c1/c1_Compiler.hpp" #include "opto/c2compiler.hpp" bool TieredThresholdPolicy::call_predicate_helper(const methodHandle& method, CompLevel cur_level, int i, int b, double scale) { double threshold_scaling; if (CompilerOracle::has_option_value(method, "CompileThresholdScaling", threshold_scaling)) { scale *= threshold_scaling; } switch(cur_level) { case CompLevel_aot: if (CompilationModeFlag::disable_intermediate()) { return (i >= Tier0AOTInvocationThreshold * scale) || (i >= Tier0AOTMinInvocationThreshold * scale && i + b >= Tier0AOTCompileThreshold * scale); } else { return (i >= Tier3AOTInvocationThreshold * scale) || (i >= Tier3AOTMinInvocationThreshold * scale && i + b >= Tier3AOTCompileThreshold * scale); } case CompLevel_none: if (CompilationModeFlag::disable_intermediate()) { return (i >= Tier40InvocationThreshold * scale) || (i >= Tier40MinInvocationThreshold * scale && i + b >= Tier40CompileThreshold * scale); } // Fall through case CompLevel_limited_profile: return (i >= Tier3InvocationThreshold * scale) || (i >= Tier3MinInvocationThreshold * scale && i + b >= Tier3CompileThreshold * scale); case CompLevel_full_profile: return (i >= Tier4InvocationThreshold * scale) || (i >= Tier4MinInvocationThreshold * scale && i + b >= Tier4CompileThreshold * scale); default: return true; } } bool TieredThresholdPolicy::loop_predicate_helper(const methodHandle& method, CompLevel cur_level, int i, int b, double scale) { double threshold_scaling; if (CompilerOracle::has_option_value(method, "CompileThresholdScaling", threshold_scaling)) { scale *= threshold_scaling; } switch(cur_level) { case CompLevel_aot: if (CompilationModeFlag::disable_intermediate()) { return b >= Tier0AOTBackEdgeThreshold * scale; } else { return b >= Tier3AOTBackEdgeThreshold * scale; } case CompLevel_none: if (CompilationModeFlag::disable_intermediate()) { return b >= Tier40BackEdgeThreshold * scale; } // Fall through case CompLevel_limited_profile: return b >= Tier3BackEdgeThreshold * scale; case CompLevel_full_profile: return b >= Tier4BackEdgeThreshold * scale; default: return true; } } // Simple methods are as good being compiled with C1 as C2. // Determine if a given method is such a case. bool TieredThresholdPolicy::is_trivial(Method* method) { if (method->is_accessor() || method->is_constant_getter()) { return true; } return false; } bool TieredThresholdPolicy::force_comp_at_level_simple(const methodHandle& method) { if (CompilationModeFlag::quick_internal()) { #if INCLUDE_JVMCI if (UseJVMCICompiler) { AbstractCompiler* comp = CompileBroker::compiler(CompLevel_full_optimization); if (comp != NULL && comp->is_jvmci() && ((JVMCICompiler*) comp)->force_comp_at_level_simple(method)) { return true; } } #endif } return false; } CompLevel TieredThresholdPolicy::comp_level(Method* method) { CompiledMethod *nm = method->code(); if (nm != NULL && nm->is_in_use()) { return (CompLevel)nm->comp_level(); } return CompLevel_none; } void TieredThresholdPolicy::print_counters(const char* prefix, Method* m) { int invocation_count = m->invocation_count(); int backedge_count = m->backedge_count(); MethodData* mdh = m->method_data(); int mdo_invocations = 0, mdo_backedges = 0; int mdo_invocations_start = 0, mdo_backedges_start = 0; if (mdh != NULL) { mdo_invocations = mdh->invocation_count(); mdo_backedges = mdh->backedge_count(); mdo_invocations_start = mdh->invocation_count_start(); mdo_backedges_start = mdh->backedge_count_start(); } tty->print(" %stotal=%d,%d %smdo=%d(%d),%d(%d)", prefix, invocation_count, backedge_count, prefix, mdo_invocations, mdo_invocations_start, mdo_backedges, mdo_backedges_start); tty->print(" %smax levels=%d,%d", prefix, m->highest_comp_level(), m->highest_osr_comp_level()); } // Print an event. void TieredThresholdPolicy::print_event(EventType type, Method* m, Method* im, int bci, CompLevel level) { bool inlinee_event = m != im; ttyLocker tty_lock; tty->print("%lf: [", os::elapsedTime()); switch(type) { case CALL: tty->print("call"); break; case LOOP: tty->print("loop"); break; case COMPILE: tty->print("compile"); break; case REMOVE_FROM_QUEUE: tty->print("remove-from-queue"); break; case UPDATE_IN_QUEUE: tty->print("update-in-queue"); break; case REPROFILE: tty->print("reprofile"); break; case MAKE_NOT_ENTRANT: tty->print("make-not-entrant"); break; default: tty->print("unknown"); } tty->print(" level=%d ", level); ResourceMark rm; char *method_name = m->name_and_sig_as_C_string(); tty->print("[%s", method_name); if (inlinee_event) { char *inlinee_name = im->name_and_sig_as_C_string(); tty->print(" [%s]] ", inlinee_name); } else tty->print("] "); tty->print("@%d queues=%d,%d", bci, CompileBroker::queue_size(CompLevel_full_profile), CompileBroker::queue_size(CompLevel_full_optimization)); tty->print(" rate="); if (m->prev_time() == 0) tty->print("n/a"); else tty->print("%f", m->rate()); tty->print(" k=%.2lf,%.2lf", threshold_scale(CompLevel_full_profile, Tier3LoadFeedback), threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback)); if (type != COMPILE) { print_counters("", m); if (inlinee_event) { print_counters("inlinee ", im); } tty->print(" compilable="); bool need_comma = false; if (!m->is_not_compilable(CompLevel_full_profile)) { tty->print("c1"); need_comma = true; } if (!m->is_not_osr_compilable(CompLevel_full_profile)) { if (need_comma) tty->print(","); tty->print("c1-osr"); need_comma = true; } if (!m->is_not_compilable(CompLevel_full_optimization)) { if (need_comma) tty->print(","); tty->print("c2"); need_comma = true; } if (!m->is_not_osr_compilable(CompLevel_full_optimization)) { if (need_comma) tty->print(","); tty->print("c2-osr"); } tty->print(" status="); if (m->queued_for_compilation()) { tty->print("in-queue"); } else tty->print("idle"); } tty->print_cr("]"); } void TieredThresholdPolicy::initialize() { int count = CICompilerCount; bool c1_only = TieredStopAtLevel < CompLevel_full_optimization || CompilationModeFlag::quick_only(); bool c2_only = CompilationModeFlag::high_only(); #ifdef _LP64 // Turn on ergonomic compiler count selection if (FLAG_IS_DEFAULT(CICompilerCountPerCPU) && FLAG_IS_DEFAULT(CICompilerCount)) { FLAG_SET_DEFAULT(CICompilerCountPerCPU, true); } if (CICompilerCountPerCPU) { // Simple log n seems to grow too slowly for tiered, try something faster: log n * log log n int log_cpu = log2_int(os::active_processor_count()); int loglog_cpu = log2_int(MAX2(log_cpu, 1)); count = MAX2(log_cpu * loglog_cpu * 3 / 2, 2); // Make sure there is enough space in the code cache to hold all the compiler buffers size_t c1_size = Compiler::code_buffer_size(); size_t c2_size = C2Compiler::initial_code_buffer_size(); size_t buffer_size = c1_only ? c1_size : (c1_size/3 + 2*c2_size/3); int max_count = (ReservedCodeCacheSize - (CodeCacheMinimumUseSpace DEBUG_ONLY(* 3))) / (int)buffer_size; if (count > max_count) { // Lower the compiler count such that all buffers fit into the code cache count = MAX2(max_count, c1_only ? 1 : 2); } FLAG_SET_ERGO(CICompilerCount, count); } #else // On 32-bit systems, the number of compiler threads is limited to 3. // On these systems, the virtual address space available to the JVM // is usually limited to 2-4 GB (the exact value depends on the platform). // As the compilers (especially C2) can consume a large amount of // memory, scaling the number of compiler threads with the number of // available cores can result in the exhaustion of the address space /// available to the VM and thus cause the VM to crash. if (FLAG_IS_DEFAULT(CICompilerCount)) { count = 3; FLAG_SET_ERGO(CICompilerCount, count); } #endif if (c1_only) { // No C2 compiler thread required set_c1_count(count); } else if (c2_only) { set_c2_count(count); } else { set_c1_count(MAX2(count / 3, 1)); set_c2_count(MAX2(count - c1_count(), 1)); } assert(count == c1_count() + c2_count(), "inconsistent compiler thread count"); // Some inlining tuning #ifdef X86 if (FLAG_IS_DEFAULT(InlineSmallCode)) { FLAG_SET_DEFAULT(InlineSmallCode, 2000); } #endif #if defined AARCH64 if (FLAG_IS_DEFAULT(InlineSmallCode)) { FLAG_SET_DEFAULT(InlineSmallCode, 2500); } #endif set_increase_threshold_at_ratio(); set_start_time(nanos_to_millis(os::javaTimeNanos())); } #ifdef ASSERT bool TieredThresholdPolicy::verify_level(CompLevel level) { // AOT and interpreter levels are always valid. if (level == CompLevel_aot || level == CompLevel_none) { return true; } if (CompilationModeFlag::normal()) { return true; } else if (CompilationModeFlag::quick_only()) { return level == CompLevel_simple; } else if (CompilationModeFlag::high_only()) { return level == CompLevel_full_optimization; } else if (CompilationModeFlag::high_only_quick_internal()) { return level == CompLevel_full_optimization || level == CompLevel_simple; } return false; } #endif CompLevel TieredThresholdPolicy::limit_level(CompLevel level) { if (CompilationModeFlag::quick_only()) { level = MIN2(level, CompLevel_simple); } assert(verify_level(level), "Invalid compilation level %d", level); if (level <= TieredStopAtLevel) { return level; } // Some compilation levels are not valid depending on a compilation mode: // a) quick_only - levels 2,3,4 are invalid; levels -1,0,1 are valid; // b) high_only - levels 1,2,3 are invalid; levels -1,0,4 are valid; // c) high_only_quick_internal - levels 2,3 are invalid; levels -1,0,1,4 are valid. // The invalid levels are actually sequential so a single comparison is sufficient. // Down here we already have (level > TieredStopAtLevel), which also implies that // (TieredStopAtLevel < Highest Possible Level), so we need to return a level that is: // a) a max level that is strictly less than the highest for a given compilation mode // b) less or equal to TieredStopAtLevel if (CompilationModeFlag::normal() || CompilationModeFlag::quick_only()) { return (CompLevel)TieredStopAtLevel; } if (CompilationModeFlag::high_only() || CompilationModeFlag::high_only_quick_internal()) { return MIN2(CompLevel_none, (CompLevel)TieredStopAtLevel); } ShouldNotReachHere(); return CompLevel_any; } CompLevel TieredThresholdPolicy::initial_compile_level_helper(const methodHandle& method) { if (CompilationModeFlag::normal()) { return CompLevel_full_profile; } else if (CompilationModeFlag::quick_only()) { return CompLevel_simple; } else if (CompilationModeFlag::high_only()) { return CompLevel_full_optimization; } else if (CompilationModeFlag::high_only_quick_internal()) { if (force_comp_at_level_simple(method)) { return CompLevel_simple; } else { return CompLevel_full_optimization; } } ShouldNotReachHere(); return CompLevel_any; } CompLevel TieredThresholdPolicy::initial_compile_level(const methodHandle& method) { return limit_level(initial_compile_level_helper(method)); } // Set carry flags on the counters if necessary void TieredThresholdPolicy::handle_counter_overflow(Method* method) { MethodCounters *mcs = method->method_counters(); if (mcs != NULL) { mcs->invocation_counter()->set_carry_on_overflow(); mcs->backedge_counter()->set_carry_on_overflow(); } MethodData* mdo = method->method_data(); if (mdo != NULL) { mdo->invocation_counter()->set_carry_on_overflow(); mdo->backedge_counter()->set_carry_on_overflow(); } } // Called with the queue locked and with at least one element CompileTask* TieredThresholdPolicy::select_task(CompileQueue* compile_queue) { CompileTask *max_blocking_task = NULL; CompileTask *max_task = NULL; Method* max_method = NULL; jlong t = nanos_to_millis(os::javaTimeNanos()); // Iterate through the queue and find a method with a maximum rate. for (CompileTask* task = compile_queue->first(); task != NULL;) { CompileTask* next_task = task->next(); Method* method = task->method(); // If a method was unloaded or has been stale for some time, remove it from the queue. // Blocking tasks and tasks submitted from whitebox API don't become stale if (task->is_unloaded() || (task->can_become_stale() && is_stale(t, TieredCompileTaskTimeout, method) && !is_old(method))) { if (!task->is_unloaded()) { if (PrintTieredEvents) { print_event(REMOVE_FROM_QUEUE, method, method, task->osr_bci(), (CompLevel) task->comp_level()); } method->clear_queued_for_compilation(); } compile_queue->remove_and_mark_stale(task); task = next_task; continue; } update_rate(t, method); if (max_task == NULL || compare_methods(method, max_method)) { // Select a method with the highest rate max_task = task; max_method = method; } if (task->is_blocking()) { if (max_blocking_task == NULL || compare_methods(method, max_blocking_task->method())) { max_blocking_task = task; } } task = next_task; } if (max_blocking_task != NULL) { // In blocking compilation mode, the CompileBroker will make // compilations submitted by a JVMCI compiler thread non-blocking. These // compilations should be scheduled after all blocking compilations // to service non-compiler related compilations sooner and reduce the // chance of such compilations timing out. max_task = max_blocking_task; max_method = max_task->method(); } methodHandle max_method_h(Thread::current(), max_method); if (max_task != NULL && max_task->comp_level() == CompLevel_full_profile && TieredStopAtLevel > CompLevel_full_profile && max_method != NULL && is_method_profiled(max_method_h)) { max_task->set_comp_level(CompLevel_limited_profile); if (CompileBroker::compilation_is_complete(max_method_h, max_task->osr_bci(), CompLevel_limited_profile)) { if (PrintTieredEvents) { print_event(REMOVE_FROM_QUEUE, max_method, max_method, max_task->osr_bci(), (CompLevel)max_task->comp_level()); } compile_queue->remove_and_mark_stale(max_task); max_method->clear_queued_for_compilation(); return NULL; } if (PrintTieredEvents) { print_event(UPDATE_IN_QUEUE, max_method, max_method, max_task->osr_bci(), (CompLevel)max_task->comp_level()); } } return max_task; } void TieredThresholdPolicy::reprofile(ScopeDesc* trap_scope, bool is_osr) { for (ScopeDesc* sd = trap_scope;; sd = sd->sender()) { if (PrintTieredEvents) { print_event(REPROFILE, sd->method(), sd->method(), InvocationEntryBci, CompLevel_none); } MethodData* mdo = sd->method()->method_data(); if (mdo != NULL) { mdo->reset_start_counters(); } if (sd->is_top()) break; } } nmethod* TieredThresholdPolicy::event(const methodHandle& method, const methodHandle& inlinee, int branch_bci, int bci, CompLevel comp_level, CompiledMethod* nm, JavaThread* thread) { if (comp_level == CompLevel_none && JvmtiExport::can_post_interpreter_events() && thread->is_interp_only_mode()) { return NULL; } if (ReplayCompiles) { // Don't trigger other compiles in testing mode return NULL; } handle_counter_overflow(method()); if (method() != inlinee()) { handle_counter_overflow(inlinee()); } if (PrintTieredEvents) { print_event(bci == InvocationEntryBci ? CALL : LOOP, method(), inlinee(), bci, comp_level); } if (bci == InvocationEntryBci) { method_invocation_event(method, inlinee, comp_level, nm, thread); } else { // method == inlinee if the event originated in the main method method_back_branch_event(method, inlinee, bci, comp_level, nm, thread); // Check if event led to a higher level OSR compilation CompLevel expected_comp_level = comp_level; if (!CompilationModeFlag::disable_intermediate() && inlinee->is_not_osr_compilable(expected_comp_level)) { // It's not possble to reach the expected level so fall back to simple. expected_comp_level = CompLevel_simple; } nmethod* osr_nm = inlinee->lookup_osr_nmethod_for(bci, expected_comp_level, false); assert(osr_nm == NULL || osr_nm->comp_level() >= expected_comp_level, "lookup_osr_nmethod_for is broken"); if (osr_nm != NULL) { // Perform OSR with new nmethod return osr_nm; } } return NULL; } // Check if the method can be compiled, change level if necessary void TieredThresholdPolicy::compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) { assert(verify_level(level) && level <= TieredStopAtLevel, "Invalid compilation level %d", level); if (level == CompLevel_none) { if (mh->has_compiled_code()) { // Happens when we switch from AOT to interpreter to profile. MutexLocker ml(Compile_lock); NoSafepointVerifier nsv; if (mh->has_compiled_code()) { mh->code()->make_not_used(); } // Deoptimize immediately (we don't have to wait for a compile). RegisterMap map(thread, false); frame fr = thread->last_frame().sender(&map); Deoptimization::deoptimize_frame(thread, fr.id()); } return; } if (level == CompLevel_aot) { if (mh->has_aot_code()) { if (PrintTieredEvents) { print_event(COMPILE, mh(), mh(), bci, level); } MutexLocker ml(Compile_lock); NoSafepointVerifier nsv; if (mh->has_aot_code() && mh->code() != mh->aot_code()) { mh->aot_code()->make_entrant(); if (mh->has_compiled_code()) { mh->code()->make_not_entrant(); } MutexLocker pl(CompiledMethod_lock, Mutex::_no_safepoint_check_flag); Method::set_code(mh, mh->aot_code()); } } return; } if (!CompilationModeFlag::disable_intermediate()) { // Check if the method can be compiled. If it cannot be compiled with C1, continue profiling // in the interpreter and then compile with C2 (the transition function will request that, // see common() ). If the method cannot be compiled with C2 but still can with C1, compile it with // pure C1. if ((bci == InvocationEntryBci && !can_be_compiled(mh, level))) { if (level == CompLevel_full_optimization && can_be_compiled(mh, CompLevel_simple)) { compile(mh, bci, CompLevel_simple, thread); } return; } if ((bci != InvocationEntryBci && !can_be_osr_compiled(mh, level))) { if (level == CompLevel_full_optimization && can_be_osr_compiled(mh, CompLevel_simple)) { nmethod* osr_nm = mh->lookup_osr_nmethod_for(bci, CompLevel_simple, false); if (osr_nm != NULL && osr_nm->comp_level() > CompLevel_simple) { // Invalidate the existing OSR nmethod so that a compile at CompLevel_simple is permitted. osr_nm->make_not_entrant(); } compile(mh, bci, CompLevel_simple, thread); } return; } } if (bci != InvocationEntryBci && mh->is_not_osr_compilable(level)) { return; } if (!CompileBroker::compilation_is_in_queue(mh)) { if (PrintTieredEvents) { print_event(COMPILE, mh(), mh(), bci, level); } int hot_count = (bci == InvocationEntryBci) ? mh->invocation_count() : mh->backedge_count(); update_rate(nanos_to_millis(os::javaTimeNanos()), mh()); CompileBroker::compile_method(mh, bci, level, mh, hot_count, CompileTask::Reason_Tiered, thread); } } // update_rate() is called from select_task() while holding a compile queue lock. void TieredThresholdPolicy::update_rate(jlong t, Method* m) { // Skip update if counters are absent. // Can't allocate them since we are holding compile queue lock. if (m->method_counters() == NULL) return; if (is_old(m)) { // We don't remove old methods from the queue, // so we can just zero the rate. m->set_rate(0); return; } // We don't update the rate if we've just came out of a safepoint. // delta_s is the time since last safepoint in milliseconds. jlong delta_s = t - SafepointTracing::end_of_last_safepoint_ms(); jlong delta_t = t - (m->prev_time() != 0 ? m->prev_time() : start_time()); // milliseconds since the last measurement // How many events were there since the last time? int event_count = m->invocation_count() + m->backedge_count(); int delta_e = event_count - m->prev_event_count(); // We should be running for at least 1ms. if (delta_s >= TieredRateUpdateMinTime) { // And we must've taken the previous point at least 1ms before. if (delta_t >= TieredRateUpdateMinTime && delta_e > 0) { m->set_prev_time(t); m->set_prev_event_count(event_count); m->set_rate((float)delta_e / (float)delta_t); // Rate is events per millisecond } else { if (delta_t > TieredRateUpdateMaxTime && delta_e == 0) { // If nothing happened for 25ms, zero the rate. Don't modify prev values. m->set_rate(0); } } } } // Check if this method has been stale for a given number of milliseconds. // See select_task(). bool TieredThresholdPolicy::is_stale(jlong t, jlong timeout, Method* m) { jlong delta_s = t - SafepointTracing::end_of_last_safepoint_ms(); jlong delta_t = t - m->prev_time(); if (delta_t > timeout && delta_s > timeout) { int event_count = m->invocation_count() + m->backedge_count(); int delta_e = event_count - m->prev_event_count(); // Return true if there were no events. return delta_e == 0; } return false; } // We don't remove old methods from the compile queue even if they have // very low activity. See select_task(). bool TieredThresholdPolicy::is_old(Method* method) { return method->invocation_count() > 50000 || method->backedge_count() > 500000; } double TieredThresholdPolicy::weight(Method* method) { return (double)(method->rate() + 1) * (method->invocation_count() + 1) * (method->backedge_count() + 1); } // Apply heuristics and return true if x should be compiled before y bool TieredThresholdPolicy::compare_methods(Method* x, Method* y) { if (x->highest_comp_level() > y->highest_comp_level()) { // recompilation after deopt return true; } else if (x->highest_comp_level() == y->highest_comp_level()) { if (weight(x) > weight(y)) { return true; } } return false; } // Is method profiled enough? bool TieredThresholdPolicy::is_method_profiled(const methodHandle& method) { MethodData* mdo = method->method_data(); if (mdo != NULL) { int i = mdo->invocation_count_delta(); int b = mdo->backedge_count_delta(); return call_predicate_helper(method, CompilationModeFlag::disable_intermediate() ? CompLevel_none : CompLevel_full_profile, i, b, 1); } return false; } double TieredThresholdPolicy::threshold_scale(CompLevel level, int feedback_k) { int comp_count = compiler_count(level); if (comp_count > 0) { double queue_size = CompileBroker::queue_size(level); double k = queue_size / (feedback_k * comp_count) + 1; // Increase C1 compile threshold when the code cache is filled more // than specified by IncreaseFirstTierCompileThresholdAt percentage. // The main intention is to keep enough free space for C2 compiled code // to achieve peak performance if the code cache is under stress. if (!CompilationModeFlag::disable_intermediate() && TieredStopAtLevel == CompLevel_full_optimization && level != CompLevel_full_optimization) { double current_reverse_free_ratio = CodeCache::reverse_free_ratio(CodeCache::get_code_blob_type(level)); if (current_reverse_free_ratio > _increase_threshold_at_ratio) { k *= exp(current_reverse_free_ratio - _increase_threshold_at_ratio); } } return k; } return 1; } // Call and loop predicates determine whether a transition to a higher // compilation level should be performed (pointers to predicate functions // are passed to common()). // Tier?LoadFeedback is basically a coefficient that determines of // how many methods per compiler thread can be in the queue before // the threshold values double. bool TieredThresholdPolicy::loop_predicate(int i, int b, CompLevel cur_level, const methodHandle& method) { double k = 1; switch(cur_level) { case CompLevel_aot: { k = CompilationModeFlag::disable_intermediate() ? 1 : threshold_scale(CompLevel_full_profile, Tier3LoadFeedback); break; } case CompLevel_none: { if (CompilationModeFlag::disable_intermediate()) { k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback); break; } } // Fall through case CompLevel_limited_profile: { k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback); break; } case CompLevel_full_profile: { k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback); break; } default: return true; } return loop_predicate_helper(method, cur_level, i, b, k); } bool TieredThresholdPolicy::call_predicate(int i, int b, CompLevel cur_level, const methodHandle& method) { double k = 1; switch(cur_level) { case CompLevel_aot: { k = CompilationModeFlag::disable_intermediate() ? 1 : threshold_scale(CompLevel_full_profile, Tier3LoadFeedback); break; } case CompLevel_none: { if (CompilationModeFlag::disable_intermediate()) { k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback); break; } } // Fall through case CompLevel_limited_profile: { k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback); break; } case CompLevel_full_profile: { k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback); break; } default: return true; } return call_predicate_helper(method, cur_level, i, b, k); } // Determine is a method is mature. bool TieredThresholdPolicy::is_mature(Method* method) { methodHandle mh(Thread::current(), method); if (is_trivial(method) || force_comp_at_level_simple(mh)) return true; MethodData* mdo = method->method_data(); if (mdo != NULL) { int i = mdo->invocation_count(); int b = mdo->backedge_count(); double k = ProfileMaturityPercentage / 100.0; CompLevel main_profile_level = CompilationModeFlag::disable_intermediate() ? CompLevel_none : CompLevel_full_profile; return call_predicate_helper(mh, main_profile_level, i, b, k) || loop_predicate_helper(mh, main_profile_level, i, b, k); } return false; } // If a method is old enough and is still in the interpreter we would want to // start profiling without waiting for the compiled method to arrive. // We also take the load on compilers into the account. bool TieredThresholdPolicy::should_create_mdo(const methodHandle& method, CompLevel cur_level) { if (cur_level != CompLevel_none || force_comp_at_level_simple(method)) { return false; } int i = method->invocation_count(); int b = method->backedge_count(); double k = Tier0ProfilingStartPercentage / 100.0; // If the top level compiler is not keeping up, delay profiling. if (CompileBroker::queue_size(CompLevel_full_optimization) <= (CompilationModeFlag::disable_intermediate() ? Tier0Delay : Tier3DelayOn) * compiler_count(CompLevel_full_optimization)) { return call_predicate_helper(method, CompLevel_none, i, b, k) || loop_predicate_helper(method, CompLevel_none, i, b, k); } return false; } // Inlining control: if we're compiling a profiled method with C1 and the callee // is known to have OSRed in a C2 version, don't inline it. bool TieredThresholdPolicy::should_not_inline(ciEnv* env, ciMethod* callee) { CompLevel comp_level = (CompLevel)env->comp_level(); if (comp_level == CompLevel_full_profile || comp_level == CompLevel_limited_profile) { return callee->highest_osr_comp_level() == CompLevel_full_optimization; } return false; } // Create MDO if necessary. void TieredThresholdPolicy::create_mdo(const methodHandle& mh, JavaThread* THREAD) { if (mh->is_native() || mh->is_abstract() || mh->is_accessor() || mh->is_constant_getter()) { return; } if (mh->method_data() == NULL) { Method::build_interpreter_method_data(mh, CHECK_AND_CLEAR); } } /* * Method states: * 0 - interpreter (CompLevel_none) * 1 - pure C1 (CompLevel_simple) * 2 - C1 with invocation and backedge counting (CompLevel_limited_profile) * 3 - C1 with full profiling (CompLevel_full_profile) * 4 - C2 or Graal (CompLevel_full_optimization) * * Common state transition patterns: * a. 0 -> 3 -> 4. * The most common path. But note that even in this straightforward case * profiling can start at level 0 and finish at level 3. * * b. 0 -> 2 -> 3 -> 4. * This case occurs when the load on C2 is deemed too high. So, instead of transitioning * into state 3 directly and over-profiling while a method is in the C2 queue we transition to * level 2 and wait until the load on C2 decreases. This path is disabled for OSRs. * * c. 0 -> (3->2) -> 4. * In this case we enqueue a method for compilation at level 3, but the C1 queue is long enough * to enable the profiling to fully occur at level 0. In this case we change the compilation level * of the method to 2 while the request is still in-queue, because it'll allow it to run much faster * without full profiling while c2 is compiling. * * d. 0 -> 3 -> 1 or 0 -> 2 -> 1. * After a method was once compiled with C1 it can be identified as trivial and be compiled to * level 1. These transition can also occur if a method can't be compiled with C2 but can with C1. * * e. 0 -> 4. * This can happen if a method fails C1 compilation (it will still be profiled in the interpreter) * or because of a deopt that didn't require reprofiling (compilation won't happen in this case because * the compiled version already exists). * * Note that since state 0 can be reached from any other state via deoptimization different loops * are possible. * */ // Common transition function. Given a predicate determines if a method should transition to another level. CompLevel TieredThresholdPolicy::common(Predicate p, const methodHandle& method, CompLevel cur_level, bool disable_feedback) { CompLevel next_level = cur_level; int i = method->invocation_count(); int b = method->backedge_count(); if (force_comp_at_level_simple(method)) { next_level = CompLevel_simple; } else { if (!CompilationModeFlag::disable_intermediate() && is_trivial(method())) { next_level = CompLevel_simple; } else { switch(cur_level) { default: break; case CompLevel_aot: if (CompilationModeFlag::disable_intermediate()) { if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <= Tier0Delay * compiler_count(CompLevel_full_optimization) && (this->*p)(i, b, cur_level, method))) { next_level = CompLevel_none; } } else { // If we were at full profile level, would we switch to full opt? if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) { next_level = CompLevel_full_optimization; } else if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <= Tier3DelayOff * compiler_count(CompLevel_full_optimization) && (this->*p)(i, b, cur_level, method))) { next_level = CompLevel_full_profile; } } break; case CompLevel_none: if (CompilationModeFlag::disable_intermediate()) { MethodData* mdo = method->method_data(); if (mdo != NULL) { // If mdo exists that means we are in a normal profiling mode. int mdo_i = mdo->invocation_count_delta(); int mdo_b = mdo->backedge_count_delta(); if ((this->*p)(mdo_i, mdo_b, cur_level, method)) { next_level = CompLevel_full_optimization; } } } else { // If we were at full profile level, would we switch to full opt? if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) { next_level = CompLevel_full_optimization; } else if ((this->*p)(i, b, cur_level, method)) { #if INCLUDE_JVMCI if (EnableJVMCI && UseJVMCICompiler) { // Since JVMCI takes a while to warm up, its queue inevitably backs up during // early VM execution. As of 2014-06-13, JVMCI's inliner assumes that the root // compilation method and all potential inlinees have mature profiles (which // includes type profiling). If it sees immature profiles, JVMCI's inliner // can perform pathologically bad (e.g., causing OutOfMemoryErrors due to // exploring/inlining too many graphs). Since a rewrite of the inliner is // in progress, we simply disable the dialing back heuristic for now and will // revisit this decision once the new inliner is completed. next_level = CompLevel_full_profile; } else #endif { // C1-generated fully profiled code is about 30% slower than the limited profile // code that has only invocation and backedge counters. The observation is that // if C2 queue is large enough we can spend too much time in the fully profiled code // while waiting for C2 to pick the method from the queue. To alleviate this problem // we introduce a feedback on the C2 queue size. If the C2 queue is sufficiently long // we choose to compile a limited profiled version and then recompile with full profiling // when the load on C2 goes down. if (!disable_feedback && CompileBroker::queue_size(CompLevel_full_optimization) > Tier3DelayOn * compiler_count(CompLevel_full_optimization)) { next_level = CompLevel_limited_profile; } else { next_level = CompLevel_full_profile; } } } } break; case CompLevel_limited_profile: if (is_method_profiled(method)) { // Special case: we got here because this method was fully profiled in the interpreter. next_level = CompLevel_full_optimization; } else { MethodData* mdo = method->method_data(); if (mdo != NULL) { if (mdo->would_profile()) { if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <= Tier3DelayOff * compiler_count(CompLevel_full_optimization) && (this->*p)(i, b, cur_level, method))) { next_level = CompLevel_full_profile; } } else { next_level = CompLevel_full_optimization; } } else { // If there is no MDO we need to profile if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <= Tier3DelayOff * compiler_count(CompLevel_full_optimization) && (this->*p)(i, b, cur_level, method))) { next_level = CompLevel_full_profile; } } } break; case CompLevel_full_profile: { MethodData* mdo = method->method_data(); if (mdo != NULL) { if (mdo->would_profile()) { int mdo_i = mdo->invocation_count_delta(); int mdo_b = mdo->backedge_count_delta(); if ((this->*p)(mdo_i, mdo_b, cur_level, method)) { next_level = CompLevel_full_optimization; } } else { next_level = CompLevel_full_optimization; } } } break; } } } return limit_level(next_level); } // Determine if a method should be compiled with a normal entry point at a different level. CompLevel TieredThresholdPolicy::call_event(const methodHandle& method, CompLevel cur_level, JavaThread* thread) { CompLevel osr_level = MIN2((CompLevel) method->highest_osr_comp_level(), common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true)); CompLevel next_level = common(&TieredThresholdPolicy::call_predicate, method, cur_level); // If OSR method level is greater than the regular method level, the levels should be // equalized by raising the regular method level in order to avoid OSRs during each // invocation of the method. if (osr_level == CompLevel_full_optimization && cur_level == CompLevel_full_profile) { MethodData* mdo = method->method_data(); guarantee(mdo != NULL, "MDO should not be NULL"); if (mdo->invocation_count() >= 1) { next_level = CompLevel_full_optimization; } } else { next_level = MAX2(osr_level, next_level); } return next_level; } // Determine if we should do an OSR compilation of a given method. CompLevel TieredThresholdPolicy::loop_event(const methodHandle& method, CompLevel cur_level, JavaThread* thread) { CompLevel next_level = common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true); if (cur_level == CompLevel_none) { // If there is a live OSR method that means that we deopted to the interpreter // for the transition. CompLevel osr_level = MIN2((CompLevel)method->highest_osr_comp_level(), next_level); if (osr_level > CompLevel_none) { return osr_level; } } return next_level; } bool TieredThresholdPolicy::maybe_switch_to_aot(const methodHandle& mh, CompLevel cur_level, CompLevel next_level, JavaThread* thread) { if (UseAOT) { if (cur_level == CompLevel_full_profile || cur_level == CompLevel_none) { // If the current level is full profile or interpreter and we're switching to any other level, // activate the AOT code back first so that we won't waste time overprofiling. compile(mh, InvocationEntryBci, CompLevel_aot, thread); // Fall through for JIT compilation. } if (next_level == CompLevel_limited_profile && cur_level != CompLevel_aot && mh->has_aot_code()) { // If the next level is limited profile, use the aot code (if there is any), // since it's essentially the same thing. compile(mh, InvocationEntryBci, CompLevel_aot, thread); // Not need to JIT, we're done. return true; } } return false; } // Handle the invocation event. void TieredThresholdPolicy::method_invocation_event(const methodHandle& mh, const methodHandle& imh, CompLevel level, CompiledMethod* nm, JavaThread* thread) { if (should_create_mdo(mh, level)) { create_mdo(mh, thread); } CompLevel next_level = call_event(mh, level, thread); if (next_level != level) { if (maybe_switch_to_aot(mh, level, next_level, thread)) { // No JITting necessary return; } if (is_compilation_enabled() && !CompileBroker::compilation_is_in_queue(mh)) { compile(mh, InvocationEntryBci, next_level, thread); } } } // Handle the back branch event. Notice that we can compile the method // with a regular entry from here. void TieredThresholdPolicy::method_back_branch_event(const methodHandle& mh, const methodHandle& imh, int bci, CompLevel level, CompiledMethod* nm, JavaThread* thread) { if (should_create_mdo(mh, level)) { create_mdo(mh, thread); } // Check if MDO should be created for the inlined method if (should_create_mdo(imh, level)) { create_mdo(imh, thread); } if (is_compilation_enabled()) { CompLevel next_osr_level = loop_event(imh, level, thread); CompLevel max_osr_level = (CompLevel)imh->highest_osr_comp_level(); // At the very least compile the OSR version if (!CompileBroker::compilation_is_in_queue(imh) && (next_osr_level != level)) { compile(imh, bci, next_osr_level, thread); } // Use loop event as an opportunity to also check if there's been // enough calls. CompLevel cur_level, next_level; if (mh() != imh()) { // If there is an enclosing method if (level == CompLevel_aot) { // Recompile the enclosing method to prevent infinite OSRs. Stay at AOT level while it's compiling. if (max_osr_level != CompLevel_none && !CompileBroker::compilation_is_in_queue(mh)) { CompLevel enclosing_level = limit_level(CompLevel_full_profile); compile(mh, InvocationEntryBci, enclosing_level, thread); } } else { // Current loop event level is not AOT guarantee(nm != NULL, "Should have nmethod here"); cur_level = comp_level(mh()); next_level = call_event(mh, cur_level, thread); if (max_osr_level == CompLevel_full_optimization) { // The inlinee OSRed to full opt, we need to modify the enclosing method to avoid deopts bool make_not_entrant = false; if (nm->is_osr_method()) { // This is an osr method, just make it not entrant and recompile later if needed make_not_entrant = true; } else { if (next_level != CompLevel_full_optimization) { // next_level is not full opt, so we need to recompile the // enclosing method without the inlinee cur_level = CompLevel_none; make_not_entrant = true; } } if (make_not_entrant) { if (PrintTieredEvents) { int osr_bci = nm->is_osr_method() ? nm->osr_entry_bci() : InvocationEntryBci; print_event(MAKE_NOT_ENTRANT, mh(), mh(), osr_bci, level); } nm->make_not_entrant(); } } // Fix up next_level if necessary to avoid deopts if (next_level == CompLevel_limited_profile && max_osr_level == CompLevel_full_profile) { next_level = CompLevel_full_profile; } if (cur_level != next_level) { if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) { compile(mh, InvocationEntryBci, next_level, thread); } } } } else { cur_level = comp_level(mh()); next_level = call_event(mh, cur_level, thread); if (next_level != cur_level) { if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) { compile(mh, InvocationEntryBci, next_level, thread); } } } } } #endif