JDK14/Java14源码在线阅读
/*
* Copyright (c) 2010, 2019, 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
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*/
#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 SPARC || defined AARCH64
if (FLAG_IS_DEFAULT(InlineSmallCode)) {
FLAG_SET_DEFAULT(InlineSmallCode, 2500);
}
#endif
set_increase_threshold_at_ratio();
set_start_time(os::javaTimeMillis());
}
#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));
}
void TieredThresholdPolicy::set_carry_if_necessary(InvocationCounter *counter) {
if (!counter->carry() && counter->count() > InvocationCounter::count_limit / 2) {
counter->set_carry_flag();
}
}
// Set carry flags on the counters if necessary
void TieredThresholdPolicy::handle_counter_overflow(Method* method) {
MethodCounters *mcs = method->method_counters();
if (mcs != NULL) {
set_carry_if_necessary(mcs->invocation_counter());
set_carry_if_necessary(mcs->backedge_counter());
}
MethodData* mdo = method->method_data();
if (mdo != NULL) {
set_carry_if_necessary(mdo->invocation_counter());
set_carry_if_necessary(mdo->backedge_counter());
}
}
// 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 = os::javaTimeMillis();
// 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(os::javaTimeMillis(), 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_epoch_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_epoch_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.
}
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