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6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads

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Select number of GC threads dynamically based on heap usage and number of Java threads

Reviewed-by: johnc, ysr, jcoomes
This commit is contained in:
Jon Masamitsu 2011-08-09 10:16:01 -07:00
parent 098ed89645
commit 15070123fa
39 changed files with 1523 additions and 231 deletions
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44
hotspot/src/share/vm/utilities/workgroup.cpp
View file

@ -57,7 +57,6 @@ WorkGang::WorkGang(const char* name,
bool are_GC_task_threads,
bool are_ConcurrentGC_threads) :
AbstractWorkGang(name, are_GC_task_threads, are_ConcurrentGC_threads) {
// Save arguments.
_total_workers = workers;
}
@ -127,6 +126,12 @@ GangWorker* AbstractWorkGang::gang_worker(int i) const {
}
void WorkGang::run_task(AbstractGangTask* task) {
run_task(task, total_workers());
}
void WorkGang::run_task(AbstractGangTask* task, uint no_of_parallel_workers) {
task->set_for_termination(no_of_parallel_workers);
// This thread is executed by the VM thread which does not block
// on ordinary MutexLocker's.
MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
@ -143,22 +148,32 @@ void WorkGang::run_task(AbstractGangTask* task) {
// Tell the workers to get to work.
monitor()->notify_all();
// Wait for them to be finished
while (finished_workers() < total_workers()) {
while (finished_workers() < (int) no_of_parallel_workers) {
if (TraceWorkGang) {
tty->print_cr("Waiting in work gang %s: %d/%d finished sequence %d",
name(), finished_workers(), total_workers(),
name(), finished_workers(), no_of_parallel_workers,
_sequence_number);
}
monitor()->wait(/* no_safepoint_check */ true);
}
_task = NULL;
if (TraceWorkGang) {
tty->print_cr("/nFinished work gang %s: %d/%d sequence %d",
name(), finished_workers(), total_workers(),
tty->print_cr("\nFinished work gang %s: %d/%d sequence %d",
name(), finished_workers(), no_of_parallel_workers,
_sequence_number);
Thread* me = Thread::current();
tty->print_cr(" T: 0x%x VM_thread: %d", me, me->is_VM_thread());
}
}
void FlexibleWorkGang::run_task(AbstractGangTask* task) {
// If active_workers() is passed, _finished_workers
// must only be incremented for workers that find non_null
// work (as opposed to all those that just check that the
// task is not null).
WorkGang::run_task(task, (uint) active_workers());
}
void AbstractWorkGang::stop() {
// Tell all workers to terminate, then wait for them to become inactive.
MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
@ -168,10 +183,10 @@ void AbstractWorkGang::stop() {
_task = NULL;
_terminate = true;
monitor()->notify_all();
while (finished_workers() < total_workers()) {
while (finished_workers() < active_workers()) {
if (TraceWorkGang) {
tty->print_cr("Waiting in work gang %s: %d/%d finished",
name(), finished_workers(), total_workers());
name(), finished_workers(), active_workers());
}
monitor()->wait(/* no_safepoint_check */ true);
}
@ -275,10 +290,12 @@ void GangWorker::loop() {
// Check for new work.
if ((data.task() != NULL) &&
(data.sequence_number() != previous_sequence_number)) {
gang()->internal_note_start();
gang_monitor->notify_all();
part = gang()->started_workers() - 1;
break;
if (gang()->needs_more_workers()) {
gang()->internal_note_start();
gang_monitor->notify_all();
part = gang()->started_workers() - 1;
break;
}
}
// Nothing to do.
gang_monitor->wait(/* no_safepoint_check */ true);
@ -350,6 +367,9 @@ const char* AbstractGangTask::name() const {
#endif /* PRODUCT */
// FlexibleWorkGang
// *** WorkGangBarrierSync
WorkGangBarrierSync::WorkGangBarrierSync()
@ -411,10 +431,8 @@ bool SubTasksDone::valid() {
}
void SubTasksDone::set_n_threads(int t) {
#ifdef ASSERT
assert(_claimed == 0 || _threads_completed == _n_threads,
"should not be called while tasks are being processed!");
#endif
_n_threads = (t == 0 ? 1 : t);
}