/* * Copyright (c) 2010, 2022, 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. *
*/
int CompilationPolicy::compiler_count(CompLevel comp_level) { if (is_c1_compile(comp_level)) { return c1_count();
} elseif (is_c2_compile(comp_level)) { return c2_count();
} return 0;
}
// Returns true if m must be compiled before executing it // This is intended to force compiles for methods (usually for // debugging) that would otherwise be interpreted for some reason. bool CompilationPolicy::must_be_compiled(const methodHandle& m, int comp_level) { // Don't allow Xcomp to cause compiles in replay mode if (ReplayCompiles) returnfalse;
if (m->has_compiled_code()) returnfalse; // already compiled if (!can_be_compiled(m, comp_level)) returnfalse;
return !UseInterpreter || // must compile all methods
(AlwaysCompileLoopMethods && m->has_loops() && CompileBroker::should_compile_new_jobs()); // eagerly compile loop methods
}
void CompilationPolicy::compile_if_required(const methodHandle& m, TRAPS) { if (must_be_compiled(m)) { // This path is unusual, mostly used by the '-Xcomp' stress test mode.
if (!THREAD->can_call_java() || THREAD->is_Compiler_thread()) { // don't force compilation, resolve was on behalf of compiler return;
} if (m->method_holder()->is_not_initialized()) { // 'is_not_initialized' means not only '!is_initialized', but also that // initialization has not been started yet ('!being_initialized') // Do not force compilation of methods in uninitialized classes. // Note that doing this would throw an assert later, // in CompileBroker::compile_method. // We sometimes use the link resolver to do reflective lookups // even before classes are initialized. return;
}
CompLevel level = initial_compile_level(m); if (PrintTieredEvents) {
print_event(COMPILE, m(), m(), InvocationEntryBci, level);
}
CompileBroker::compile_method(m, InvocationEntryBci, level, methodHandle(), 0, CompileTask::Reason_MustBeCompiled, THREAD);
}
}
// Returns true if m is allowed to be compiled bool CompilationPolicy::can_be_compiled(const methodHandle& m, int comp_level) { // allow any levels for WhiteBox
assert(WhiteBoxAPI || comp_level == CompLevel_any || is_compile(comp_level), "illegal compilation level");
if (m->is_abstract()) returnfalse; if (DontCompileHugeMethods && m->code_size() > HugeMethodLimit) returnfalse;
// Math intrinsics should never be compiled as this can lead to // monotonicity problems because the interpreter will prefer the // compiled code to the intrinsic version. This can't happen in // production because the invocation counter can't be incremented // but we shouldn't expose the system to this problem in testing // modes. if (!AbstractInterpreter::can_be_compiled(m)) { returnfalse;
}
comp_level = adjust_level_for_compilability_query((CompLevel) comp_level); if (comp_level == CompLevel_any || is_compile(comp_level)) { return !m->is_not_compilable(comp_level);
} returnfalse;
}
// Returns true if m is allowed to be osr compiled bool CompilationPolicy::can_be_osr_compiled(const methodHandle& m, int comp_level) { bool result = false;
comp_level = adjust_level_for_compilability_query((CompLevel) comp_level); if (comp_level == CompLevel_any || is_compile(comp_level)) {
result = !m->is_not_osr_compilable(comp_level);
} return (result && can_be_compiled(m, comp_level));
}
CompileTask* CompilationPolicy::select_task_helper(CompileQueue* compile_queue) { // Remove unloaded methods from the queue for (CompileTask* task = compile_queue->first(); task != NULL; ) {
CompileTask* next = task->next(); if (task->is_unloaded()) {
compile_queue->remove_and_mark_stale(task);
}
task = next;
} #if INCLUDE_JVMCI if (UseJVMCICompiler && !BackgroundCompilation) { /* * 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.
*/ for (CompileTask* task = compile_queue->first(); task != NULL; task = task->next()) { if (task->is_blocking()) { return task;
}
}
} #endif return compile_queue->first();
}
// Simple methods are as good being compiled with C1 as C2. // Determine if a given method is such a case. bool CompilationPolicy::is_trivial(const methodHandle& method) { if (method->is_accessor() ||
method->is_constant_getter()) { returntrue;
} returnfalse;
}
// 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. class LoopPredicate : AllStatic { public: staticbool apply_scaled(const methodHandle& method, CompLevel cur_level, int i, int b, double scale) { double threshold_scaling; if (CompilerOracle::has_option_value(method, CompileCommand::CompileThresholdScaling, threshold_scaling)) {
scale *= threshold_scaling;
} switch(cur_level) { case CompLevel_none: case CompLevel_limited_profile: return b >= Tier3BackEdgeThreshold * scale; case CompLevel_full_profile: return b >= Tier4BackEdgeThreshold * scale; default: returntrue;
}
}
staticbool apply(const methodHandle& method, CompLevel cur_level, int i, int b) { double k = 1; switch(cur_level) { case CompLevel_none: // Fall through case CompLevel_limited_profile: {
k = CompilationPolicy::threshold_scale(CompLevel_full_profile, Tier3LoadFeedback); break;
} case CompLevel_full_profile: {
k = CompilationPolicy::threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback); break;
} default: returntrue;
} return apply_scaled(method, cur_level, i, b, k);
}
};
class CallPredicate : AllStatic { public: staticbool apply_scaled(const methodHandle& method, CompLevel cur_level, int i, int b, double scale) { double threshold_scaling; if (CompilerOracle::has_option_value(method, CompileCommand::CompileThresholdScaling, threshold_scaling)) {
scale *= threshold_scaling;
} switch(cur_level) { case CompLevel_none: 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: returntrue;
}
}
staticbool apply(const methodHandle& method, CompLevel cur_level, int i, int b) { double k = 1; switch(cur_level) { case CompLevel_none: case CompLevel_limited_profile: {
k = CompilationPolicy::threshold_scale(CompLevel_full_profile, Tier3LoadFeedback); break;
} case CompLevel_full_profile: {
k = CompilationPolicy::threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback); break;
} default: returntrue;
} return apply_scaled(method, cur_level, i, b, k);
}
};
double CompilationPolicy::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 (CompilerConfig::is_tiered() && !CompilationModeFlag::disable_intermediate() && is_c1_compile(level)) { double current_reverse_free_ratio = CodeCache::reverse_free_ratio(); if (current_reverse_free_ratio > _increase_threshold_at_ratio) {
k *= exp(current_reverse_free_ratio - _increase_threshold_at_ratio);
}
} return k;
} return 1;
}
void CompilationPolicy::print_counters(constchar* prefix, const 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 CompilationPolicy::print_event(EventType type, const Method* m, const Method* im, int bci, CompLevel level) { bool inlinee_event = m != im;
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");
}
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 CompilationPolicy::initialize() { if (!CompilerConfig::is_interpreter_only()) { int count = CICompilerCount; bool c1_only = CompilerConfig::is_c1_only(); bool c2_only = CompilerConfig::is_c2_or_jvmci_compiler_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 = log2i(os::active_processor_count()); int loglog_cpu = log2i(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 = 0; #ifdef COMPILER1
c1_size = Compiler::code_buffer_size(); #endif
size_t c2_size = 0; #ifdef COMPILER2
c2_size = C2Compiler::initial_code_buffer_size(); #endif
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
#ifdef ASSERT bool CompilationPolicy::verify_level(CompLevel level) { if (TieredCompilation && level > TieredStopAtLevel) { returnfalse;
} // Check if there is a compiler to process the requested level if (!CompilerConfig::is_c1_enabled() && is_c1_compile(level)) { returnfalse;
} if (!CompilerConfig::is_c2_or_jvmci_compiler_enabled() && is_c2_compile(level)) { returnfalse;
}
CompLevel CompilationPolicy::highest_compile_level() {
CompLevel level = CompLevel_none; // Setup the maximum level available for the current compiler configuration. if (!CompilerConfig::is_interpreter_only()) { if (CompilerConfig::is_c2_or_jvmci_compiler_enabled()) {
level = CompLevel_full_optimization;
} elseif (CompilerConfig::is_c1_enabled()) { if (CompilerConfig::is_c1_simple_only()) {
level = CompLevel_simple;
} else {
level = CompLevel_full_profile;
}
}
} // Clamp the maximum level with TieredStopAtLevel. if (TieredCompilation) {
level = MIN2(level, (CompLevel) TieredStopAtLevel);
}
// Fix it up if after the clamping it has become invalid. // Bring it monotonically down depending on the next available level for // the compilation mode. if (!CompilationModeFlag::normal()) { // 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. if (CompilationModeFlag::quick_only()) { if (level == CompLevel_limited_profile || level == CompLevel_full_profile || level == CompLevel_full_optimization) {
level = CompLevel_simple;
}
} elseif (CompilationModeFlag::high_only()) { if (level == CompLevel_simple || level == CompLevel_limited_profile || level == CompLevel_full_profile) {
level = CompLevel_none;
}
} elseif (CompilationModeFlag::high_only_quick_internal()) { if (level == CompLevel_limited_profile || level == CompLevel_full_profile) {
level = CompLevel_simple;
}
}
}
// Set carry flags on the counters if necessary void CompilationPolicy::handle_counter_overflow(const methodHandle& 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* CompilationPolicy::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(); // 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()) {
compile_queue->remove_and_mark_stale(task);
task = next_task; continue;
}
Method* method = task->method();
methodHandle mh(Thread::current(), method); if (task->can_become_stale() && is_stale(t, TieredCompileTaskTimeout, mh) && !is_old(mh)) { 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, mh); 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();
}
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 (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 = MIN2(CompLevel_full_optimization, static_cast<CompLevel>(comp_level + 1)); if (!CompilationModeFlag::disable_intermediate() && inlinee->is_not_osr_compilable(expected_comp_level)) { // It's not possible to reach the expected level so fall back to simple.
expected_comp_level = CompLevel_simple;
}
CompLevel max_osr_level = static_cast<CompLevel>(inlinee->highest_osr_comp_level()); if (max_osr_level >= expected_comp_level) { // fast check to avoid locking in a typical scenario
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 && osr_nm->comp_level() != comp_level) { // Perform OSR with new nmethod return osr_nm;
}
}
} return NULL;
}
// Check if the method can be compiled, change level if necessary void CompilationPolicy::compile(const methodHandle& mh, int bci, CompLevel level, TRAPS) {
assert(verify_level(level), "Invalid compilation level requested: %d", level);
if (level == CompLevel_none) { if (mh->has_compiled_code()) { // Happens when we switch 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).
JavaThread* jt = THREAD;
RegisterMap map(jt,
RegisterMap::UpdateMap::skip,
RegisterMap::ProcessFrames::include,
RegisterMap::WalkContinuation::skip);
frame fr = jt->last_frame().sender(&map);
Deoptimization::deoptimize_frame(jt, fr.id());
} 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 CompilationPolicy::update_rate(jlong t, const methodHandle& method) { // Skip update if counters are absent. // Can't allocate them since we are holding compile queue lock. if (method->method_counters() == NULL) return;
if (is_old(method)) { // We don't remove old methods from the queue, // so we can just zero the rate.
method->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 - (method->prev_time() != 0 ? method->prev_time() : start_time()); // milliseconds since the last measurement // How many events were there since the last time? int event_count = method->invocation_count() + method->backedge_count(); int delta_e = event_count - method->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) {
method->set_prev_time(t);
method->set_prev_event_count(event_count);
method->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.
method->set_rate(0);
}
}
}
}
// Check if this method has been stale for a given number of milliseconds. // See select_task(). bool CompilationPolicy::is_stale(jlong t, jlong timeout, const methodHandle& method) {
jlong delta_s = t - SafepointTracing::end_of_last_safepoint_ms();
jlong delta_t = t - method->prev_time(); if (delta_t > timeout && delta_s > timeout) { int event_count = method->invocation_count() + method->backedge_count(); int delta_e = event_count - method->prev_event_count(); // Return true if there were no events. return delta_e == 0;
} returnfalse;
}
// We don't remove old methods from the compile queue even if they have // very low activity. See select_task(). bool CompilationPolicy::is_old(const methodHandle& method) { int i = method->invocation_count(); int b = method->backedge_count(); double k = TieredOldPercentage / 100.0;
return CallPredicate::apply_scaled(method, CompLevel_none, i, b, k) || LoopPredicate::apply_scaled(method, CompLevel_none, i, b, k);
}
// Apply heuristics and return true if x should be compiled before y bool CompilationPolicy::compare_methods(Method* x, Method* y) { if (x->highest_comp_level() > y->highest_comp_level()) { // recompilation after deopt returntrue;
} else if (x->highest_comp_level() == y->highest_comp_level()) { if (weight(x) > weight(y)) { returntrue;
}
} returnfalse;
}
// Is method profiled enough? bool CompilationPolicy::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 CallPredicate::apply_scaled(method, CompLevel_full_profile, i, b, 1);
} returnfalse;
}
// Determine is a method is mature. bool CompilationPolicy::is_mature(Method* method) { if (Arguments::is_compiler_only()) { // Always report profiles as immature with -Xcomp returnfalse;
}
methodHandle mh(Thread::current(), method);
MethodData* mdo = method->method_data(); if (mdo != NULL) { int i = mdo->invocation_count(); int b = mdo->backedge_count(); double k = ProfileMaturityPercentage / 100.0; return CallPredicate::apply_scaled(mh, CompLevel_full_profile, i, b, k) || LoopPredicate::apply_scaled(mh, CompLevel_full_profile, i, b, k);
} returnfalse;
}
// 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 CompilationPolicy::should_create_mdo(const methodHandle& method, CompLevel cur_level) { if (cur_level != CompLevel_none || force_comp_at_level_simple(method) || CompilationModeFlag::quick_only() || !ProfileInterpreter) { returnfalse;
} if (is_old(method)) { returntrue;
} 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) <= Tier0Delay * compiler_count(CompLevel_full_optimization)) { return CallPredicate::apply_scaled(method, CompLevel_none, i, b, k) || LoopPredicate::apply_scaled(method, CompLevel_none, i, b, k);
} returnfalse;
}
// 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 CompilationPolicy::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;
} returnfalse;
}
// Create MDO if necessary. void CompilationPolicy::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_profiling_method_data(mh, CHECK_AND_CLEAR);
} if (ProfileInterpreter) {
MethodData* mdo = mh->method_data(); if (mdo != NULL) {
frame last_frame = THREAD->last_frame(); if (last_frame.is_interpreted_frame() && mh == last_frame.interpreter_frame_method()) { int bci = last_frame.interpreter_frame_bci();
address dp = mdo->bci_to_dp(bci);
last_frame.interpreter_frame_set_mdp(dp);
}
}
}
}
/* * 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. template<typename Predicate>
CompLevel CompilationPolicy::common(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 (is_trivial(method)) {
next_level = CompilationModeFlag::disable_intermediate() ? CompLevel_full_optimization : CompLevel_simple;
} else { switch(cur_level) { default: break; case CompLevel_none: // If we were at full profile level, would we switch to full opt? if (common<Predicate>(method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) {
next_level = CompLevel_full_optimization;
} elseif (!CompilationModeFlag::disable_intermediate() && Predicate::apply(method, cur_level, i, b)) { // 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) &&
Predicate::apply(method, cur_level, i, b))) {
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) &&
Predicate::apply(method, cur_level, i, b))) {
next_level = CompLevel_full_profile;
}
}
} break; case CompLevel_full_profile:
{
MethodData* mdo = method->method_data(); if (mdo != NULL) { if (mdo->would_profile() || CompilationModeFlag::disable_intermediate()) { int mdo_i = mdo->invocation_count_delta(); int mdo_b = mdo->backedge_count_delta(); if (Predicate::apply(method, cur_level, mdo_i, mdo_b)) {
next_level = CompLevel_full_optimization;
}
} else {
next_level = CompLevel_full_optimization;
}
}
} break;
}
}
} return (next_level != cur_level) ? limit_level(next_level) : next_level;
}
// Determine if a method should be compiled with a normal entry point at a different level.
CompLevel CompilationPolicy::call_event(const methodHandle& method, CompLevel cur_level, Thread* thread) {
CompLevel osr_level = MIN2((CompLevel) method->highest_osr_comp_level(), common<LoopPredicate>(method, cur_level, true));
CompLevel next_level = common<CallPredicate>(method, cur_level, is_old(method));
// 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 CompilationPolicy::loop_event(const methodHandle& method, CompLevel cur_level, Thread* thread) {
CompLevel next_level = common<LoopPredicate>(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;
}
// Handle the back branch event. Notice that we can compile the method // with a regular entry from here. void CompilationPolicy::method_back_branch_event(const methodHandle& mh, const methodHandle& imh, int bci, CompLevel level, CompiledMethod* nm, TRAPS) { 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, CHECK);
}
// 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
{
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 (!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 (!CompileBroker::compilation_is_in_queue(mh)) {
compile(mh, InvocationEntryBci, next_level, THREAD);
}
}
}
}
}
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