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Adjust heuristics for idle notifications after context disposal.

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Review URL: https://chromiumcodereview.appspot.com/9701093

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11095 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
ulan@chromium.org 2012-03-20 13:29:49 +00:00
parent 13498a1cd3
commit c7c3f8d5be
2 changed files with 64 additions and 55 deletions
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104
src/heap.cc
View File

@ -4814,11 +4814,54 @@ void Heap::EnsureHeapIsIterable() {
}
void Heap::AdvanceIdleIncrementalMarking(intptr_t step_size) {
// This flag prevents incremental marking from requesting GC via stack guard
idle_notification_will_schedule_next_gc_ = true;
incremental_marking()->Step(step_size);
idle_notification_will_schedule_next_gc_ = false;
if (incremental_marking()->IsComplete()) {
bool uncommit = false;
if (gc_count_at_last_idle_gc_ == gc_count_) {
// No GC since the last full GC, the mutator is probably not active.
isolate_->compilation_cache()->Clear();
uncommit = true;
}
CollectAllGarbage(kNoGCFlags, "idle notification: finalize incremental");
gc_count_at_last_idle_gc_ = gc_count_;
if (uncommit) {
new_space_.Shrink();
UncommitFromSpace();
}
}
}
bool Heap::IdleNotification(int hint) {
if (hint >= 1000) return IdleGlobalGC();
if (contexts_disposed_ > 0 || !FLAG_incremental_marking ||
intptr_t size_factor = Min(Max(hint, 30), 1000) / 10;
// The size factor is in range [3..100].
intptr_t step_size = size_factor * IncrementalMarking::kAllocatedThreshold;
if (contexts_disposed_ > 0) {
int mark_sweep_time = Min(TimeMarkSweepWouldTakeInMs(), 1000);
if (hint >= mark_sweep_time && !FLAG_expose_gc) {
HistogramTimerScope scope(isolate_->counters()->gc_context());
CollectAllGarbage(kReduceMemoryFootprintMask,
"idle notification: contexts disposed");
} else {
AdvanceIdleIncrementalMarking(step_size);
contexts_disposed_ = 0;
}
// Make sure that we have no pending context disposals.
// Take into account that we might have decided to delay full collection
// because incremental marking is in progress.
ASSERT((contexts_disposed_ == 0) || !incremental_marking()->IsStopped());
return false;
}
if (hint >= 1000 || !FLAG_incremental_marking ||
FLAG_expose_gc || Serializer::enabled()) {
return true;
return IdleGlobalGC();
}
// By doing small chunks of GC work in each IdleNotification,
@ -4830,9 +4873,6 @@ bool Heap::IdleNotification(int hint) {
// 3. many lazy sweep steps.
// Use mark-sweep-compact events to count incremental GCs in a round.
intptr_t size_factor = Min(Max(hint, 30), 1000) / 10;
// The size factor is in range [3..100].
intptr_t step_size = size_factor * IncrementalMarking::kAllocatedThreshold;
if (incremental_marking()->IsStopped()) {
if (!IsSweepingComplete() &&
@ -4859,32 +4899,14 @@ bool Heap::IdleNotification(int hint) {
}
if (incremental_marking()->IsStopped()) {
if (hint < 1000 && !WorthStartingGCWhenIdle()) {
if (!WorthStartingGCWhenIdle()) {
FinishIdleRound();
return true;
}
incremental_marking()->Start();
}
// This flag prevents incremental marking from requesting GC via stack guard
idle_notification_will_schedule_next_gc_ = true;
incremental_marking()->Step(step_size);
idle_notification_will_schedule_next_gc_ = false;
if (incremental_marking()->IsComplete()) {
bool uncommit = false;
if (gc_count_at_last_idle_gc_ == gc_count_) {
// No GC since the last full GC, the mutator is probably not active.
isolate_->compilation_cache()->Clear();
uncommit = true;
}
CollectAllGarbage(kNoGCFlags, "idle notification: finalize incremental");
gc_count_at_last_idle_gc_ = gc_count_;
if (uncommit) {
new_space_.Shrink();
UncommitFromSpace();
}
}
AdvanceIdleIncrementalMarking(step_size);
return false;
}
@ -4917,13 +4939,7 @@ bool Heap::IdleGlobalGC() {
}
if (number_idle_notifications_ == kIdlesBeforeScavenge) {
if (contexts_disposed_ > 0) {
HistogramTimerScope scope(isolate_->counters()->gc_context());
CollectAllGarbage(kReduceMemoryFootprintMask,
"idle notification: contexts disposed");
} else {
CollectGarbage(NEW_SPACE, "idle notification");
}
CollectGarbage(NEW_SPACE, "idle notification");
new_space_.Shrink();
last_idle_notification_gc_count_ = gc_count_;
} else if (number_idle_notifications_ == kIdlesBeforeMarkSweep) {
@ -4942,23 +4958,6 @@ bool Heap::IdleGlobalGC() {
last_idle_notification_gc_count_ = gc_count_;
number_idle_notifications_ = 0;
finished = true;
} else if (contexts_disposed_ > 0) {
if (FLAG_expose_gc) {
contexts_disposed_ = 0;
} else {
HistogramTimerScope scope(isolate_->counters()->gc_context());
CollectAllGarbage(kReduceMemoryFootprintMask,
"idle notification: contexts disposed");
last_idle_notification_gc_count_ = gc_count_;
}
// If this is the first idle notification, we reset the
// notification count to avoid letting idle notifications for
// context disposal garbage collections start a potentially too
// aggressive idle GC cycle.
if (number_idle_notifications_ <= 1) {
number_idle_notifications_ = 0;
uncommit = false;
}
} else if (number_idle_notifications_ > kIdlesBeforeMarkCompact) {
// If we have received more than kIdlesBeforeMarkCompact idle
// notifications we do not perform any cleanup because we don't
@ -4966,11 +4965,6 @@ bool Heap::IdleGlobalGC() {
finished = true;
}
// Make sure that we have no pending context disposals and
// conditionally uncommit from space.
// Take into account that we might have decided to delay full collection
// because incremental marking is in progress.
ASSERT((contexts_disposed_ == 0) || !incremental_marking()->IsStopped());
if (uncommit) UncommitFromSpace();
return finished;

15
src/heap.h
View File

@ -1966,9 +1966,24 @@ class Heap {
return incremental_marking()->WorthActivating();
}
// Estimates how many milliseconds a Mark-Sweep would take to complete.
// In idle notification handler we assume that this function will return:
// - a number less than 10 for small heaps, which are less than 8Mb.
// - a number greater than 10 for large heaps, which are greater than 32Mb.
int TimeMarkSweepWouldTakeInMs() {
// Rough estimate of how many megabytes of heap can be processed in 1 ms.
static const int kMbPerMs = 2;
int heap_size_mb = static_cast<int>(SizeOfObjects() / MB);
return heap_size_mb / kMbPerMs;
}
// Returns true if no more GC work is left.
bool IdleGlobalGC();
void AdvanceIdleIncrementalMarking(intptr_t step_size);
static const int kInitialSymbolTableSize = 2048;
static const int kInitialEvalCacheSize = 64;
static const int kInitialNumberStringCacheSize = 256;