// 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 AdvancedThresholdPolicy::should_create_mdo(methodOop method, CompLevel cur_level) {
if (cur_level == CompLevel_none &&
CompileBroker::queue_size(CompLevel_full_optimization) <=
Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {
int i = method->invocation_count();
int b = method->backedge_count();
double k = Tier0ProfilingStartPercentage / 100.0;
return call_predicate_helper<CompLevel_none>(i, b, k) || loop_predicate_helper<CompLevel_none>(i, b, k);
}
return false;
}
double AdvancedThresholdPolicy::threshold_scale(CompLevel level, int feedback_k) {
double queue_size = CompileBroker::queue_size(level);
int comp_count = compiler_count(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 ((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;
}
// Common transition function. Given a predicate determines if a method should transition to another level.
CompLevel AdvancedThresholdPolicy::common(Predicate p, methodOop method, CompLevel cur_level) {
if (is_trivial(method)) return CompLevel_simple;
CompLevel next_level = cur_level;
int i = method->invocation_count();
int b = method->backedge_count();
switch(cur_level) {
case CompLevel_none:
// If we were at full profile level, would we switch to full opt?
if (common(p, method, CompLevel_full_profile) == CompLevel_full_optimization) {
next_level = CompLevel_full_optimization;
} else if ((this->*p)(i, b, cur_level)) {
// 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 (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 {
methodDataOop mdo = method->method_data();
if (mdo != NULL) {
if (mdo->would_profile()) {
if (CompileBroker::queue_size(CompLevel_full_optimization) <=
Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
(this->*p)(i, b, cur_level)) {
next_level = CompLevel_full_profile;
}
} else {
next_level = CompLevel_full_optimization;
}
}
}
break;
case CompLevel_full_profile:
{
methodDataOop 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)) {
next_level = CompLevel_full_optimization;
}
} else {
next_level = CompLevel_full_optimization;
}
}
}
break;
}
return next_level;
}
double AdvancedThresholdPolicy::threshold_scale(CompLevel level, int feedback_k) {
double queue_size = CompileBroker::queue_size(level);
int comp_count = compiler_count(level);
double k = queue_size / (feedback_k * comp_count) + 1;
return k;
}
// Common transition function. Given a predicate determines if a method should transition to another level.
CompLevel AdvancedThresholdPolicy::common(Predicate p, Method* method, CompLevel cur_level, bool disable_feedback) {
CompLevel next_level = cur_level;
int i = method->invocation_count();
int b = method->backedge_count();
if (is_trivial(method)) {
next_level = CompLevel_simple;
} else {
switch(cur_level) {
case CompLevel_none:
// 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 (UseJVMCICompiler) {
// Since JVMCI takes a while to warm up, its queue inevitably backs up during
// early VM execution.
next_level = CompLevel_full_profile;
break;
}
#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;
}
}
}
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 MIN2(next_level, (CompLevel)TieredStopAtLevel);
}