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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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40
hotspot/src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp
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@ -181,28 +181,29 @@ class PSRefProcTaskExecutor: public AbstractRefProcTaskExecutor {
void PSRefProcTaskExecutor::execute(ProcessTask& task)
{
GCTaskQueue* q = GCTaskQueue::create();
for(uint i=0; i<ParallelGCThreads; i++) {
GCTaskManager* manager = ParallelScavengeHeap::gc_task_manager();
for(uint i=0; i < manager->active_workers(); i++) {
q->enqueue(new PSRefProcTaskProxy(task, i));
}
ParallelTaskTerminator terminator(
ParallelScavengeHeap::gc_task_manager()->workers(),
ParallelTaskTerminator terminator(manager->active_workers(),
(TaskQueueSetSuper*) PSPromotionManager::stack_array_depth());
if (task.marks_oops_alive() && ParallelGCThreads > 1) {
for (uint j=0; j<ParallelGCThreads; j++) {
if (task.marks_oops_alive() && manager->active_workers() > 1) {
for (uint j = 0; j < manager->active_workers(); j++) {
q->enqueue(new StealTask(&terminator));
}
}
ParallelScavengeHeap::gc_task_manager()->execute_and_wait(q);
manager->execute_and_wait(q);
}
void PSRefProcTaskExecutor::execute(EnqueueTask& task)
{
GCTaskQueue* q = GCTaskQueue::create();
for(uint i=0; i<ParallelGCThreads; i++) {
GCTaskManager* manager = ParallelScavengeHeap::gc_task_manager();
for(uint i=0; i < manager->active_workers(); i++) {
q->enqueue(new PSRefEnqueueTaskProxy(task, i));
}
ParallelScavengeHeap::gc_task_manager()->execute_and_wait(q);
manager->execute_and_wait(q);
}
// This method contains all heap specific policy for invoking scavenge.
@ -375,6 +376,14 @@ bool PSScavenge::invoke_no_policy() {
// Release all previously held resources
gc_task_manager()->release_all_resources();
// Set the number of GC threads to be used in this collection
gc_task_manager()->set_active_gang();
gc_task_manager()->task_idle_workers();
// Get the active number of workers here and use that value
// throughout the methods.
uint active_workers = gc_task_manager()->active_workers();
heap->set_par_threads(active_workers);
PSPromotionManager::pre_scavenge();
// We'll use the promotion manager again later.
@ -385,8 +394,9 @@ bool PSScavenge::invoke_no_policy() {
GCTaskQueue* q = GCTaskQueue::create();
for(uint i=0; i<ParallelGCThreads; i++) {
q->enqueue(new OldToYoungRootsTask(old_gen, old_top, i));
uint stripe_total = active_workers;
for(uint i=0; i < stripe_total; i++) {
q->enqueue(new OldToYoungRootsTask(old_gen, old_top, i, stripe_total));
}
q->enqueue(new SerialOldToYoungRootsTask(perm_gen, perm_top));
@ -403,10 +413,10 @@ bool PSScavenge::invoke_no_policy() {
q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::code_cache));
ParallelTaskTerminator terminator(
gc_task_manager()->workers(),
active_workers,
(TaskQueueSetSuper*) promotion_manager->stack_array_depth());
if (ParallelGCThreads>1) {
for (uint j=0; j<ParallelGCThreads; j++) {
if (active_workers > 1) {
for (uint j = 0; j < active_workers; j++) {
q->enqueue(new StealTask(&terminator));
}
}
@ -419,6 +429,7 @@ bool PSScavenge::invoke_no_policy() {
// Process reference objects discovered during scavenge
{
reference_processor()->setup_policy(false); // not always_clear
reference_processor()->set_active_mt_degree(active_workers);
PSKeepAliveClosure keep_alive(promotion_manager);
PSEvacuateFollowersClosure evac_followers(promotion_manager);
if (reference_processor()->processing_is_mt()) {
@ -622,6 +633,8 @@ bool PSScavenge::invoke_no_policy() {
// Track memory usage and detect low memory
MemoryService::track_memory_usage();
heap->update_counters();
gc_task_manager()->release_idle_workers();
}
if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
@ -804,6 +817,7 @@ void PSScavenge::initialize() {
// Initialize ref handling object for scavenging.
MemRegion mr = young_gen->reserved();
_ref_processor =
new ReferenceProcessor(mr, // span
ParallelRefProcEnabled && (ParallelGCThreads > 1), // mt processing