// Called with the queue locked and with at least one element
CompileTask* AdvancedThresholdPolicy::select_task(CompileQueue* compile_queue) {
#if INCLUDE_JVMCI
CompileTask *max_non_jvmci_task = NULL;
#endif
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();
update_rate(t, method);
if (max_task == NULL) {
max_task = task;
max_method = method;
} else {
// If a method has been stale for some time, remove it from the queue.
if (is_stale(t, TieredCompileTaskTimeout, method) && !is_old(method)) {
if (PrintTieredEvents) {
print_event(REMOVE_FROM_QUEUE, method, method, task->osr_bci(), (CompLevel)task->comp_level());
}
task->log_task_dequeued("stale");
compile_queue->remove_and_mark_stale(task);
method->clear_queued_for_compilation();
task = next_task;
continue;
}
// Select a method with a higher rate
if (compare_methods(method, max_method)) {
max_task = task;
max_method = method;
}
}
task = next_task;
}
#if INCLUDE_JVMCI
if (UseJVMCICompiler) {
if (max_non_jvmci_task != NULL) {
max_task = max_non_jvmci_task;
max_method = max_task->method();
}
}
#endif
if (max_task->comp_level() == CompLevel_full_profile && TieredStopAtLevel > CompLevel_full_profile
&& is_method_profiled(max_method)) {
max_task->set_comp_level(CompLevel_limited_profile);
if (PrintTieredEvents) {
print_event(UPDATE_IN_QUEUE, max_method, max_method, max_task->osr_bci(), (CompLevel)max_task->comp_level());
}
}
return max_task;
}
// Called with the queue locked and with at least one element
CompileTask* AdvancedThresholdPolicy::select_task(CompileQueue* compile_queue) {
CompileTask *max_task = NULL;
methodOop max_method;
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();
methodOop method = (methodOop)JNIHandles::resolve(task->method_handle());
methodDataOop mdo = method->method_data();
update_rate(t, method);
if (max_task == NULL) {
max_task = task;
max_method = method;
} else {
// If a method has been stale for some time, remove it from the queue.
if (is_stale(t, TieredCompileTaskTimeout, method) && !is_old(method)) {
if (PrintTieredEvents) {
print_event(KILL, method, method, task->osr_bci(), (CompLevel)task->comp_level());
}
CompileTaskWrapper ctw(task); // Frees the task
compile_queue->remove(task);
method->clear_queued_for_compilation();
task = next_task;
continue;
}
// Select a method with a higher rate
if (compare_methods(method, max_method)) {
max_task = task;
max_method = method;
}
}
task = next_task;
}
if (max_task->comp_level() == CompLevel_full_profile && is_method_profiled(max_method)) {
max_task->set_comp_level(CompLevel_limited_profile);
if (PrintTieredEvents) {
print_event(UPDATE, max_method, max_method, max_task->osr_bci(), (CompLevel)max_task->comp_level());
}
}
return max_task;
}
// 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;
}
// 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);
}
