GSS: Fix the bump pointer space only collection.
Fixes b/13912464 where the clear soft reference behavior accidentally
disabled the bump pointer space only collection.
Changed the collector name so that the GC logs would indicate the
generational mode and the collection mode.
Peformance enhancement: instead of triggering the whole heap
collection every 5 collections, count the bytes promoted since the
last whole heap collection and use it to decide when to trigger the
whole heap collection. This improves MemAllocTest by 5-10% (N4 and
host).
Bug: 13912464
Bug: 11650816
Bug: 9986565
Change-Id: I653a0dca62a8b54adf69abe2940a41eac70f809b
diff --git a/runtime/gc/collector/semi_space.cc b/runtime/gc/collector/semi_space.cc
index 1366858..e82d533 100644
--- a/runtime/gc/collector/semi_space.cc
+++ b/runtime/gc/collector/semi_space.cc
@@ -65,6 +65,8 @@
static constexpr bool kProtectFromSpace = true;
static constexpr bool kClearFromSpace = true;
static constexpr bool kStoreStackTraces = false;
+static constexpr bool kUseBytesPromoted = true;
+static constexpr size_t kBytesPromotedThreshold = 4 * MB;
void SemiSpace::BindBitmaps() {
timings_.StartSplit("BindBitmaps");
@@ -102,8 +104,10 @@
generational_(generational),
last_gc_to_space_end_(nullptr),
bytes_promoted_(0),
+ bytes_promoted_since_last_whole_heap_collection_(0),
whole_heap_collection_(true),
- whole_heap_collection_interval_counter_(0) {
+ whole_heap_collection_interval_counter_(0),
+ collector_name_(name_) {
}
void SemiSpace::InitializePhase() {
@@ -150,14 +154,31 @@
// collection, collect the whole heap (and reset the interval
// counter to be consistent.)
whole_heap_collection_ = true;
- whole_heap_collection_interval_counter_ = 0;
+ if (!kUseBytesPromoted) {
+ whole_heap_collection_interval_counter_ = 0;
+ }
}
if (whole_heap_collection_) {
VLOG(heap) << "Whole heap collection";
+ name_ = collector_name_ + " whole";
} else {
VLOG(heap) << "Bump pointer space only collection";
+ name_ = collector_name_ + " bps";
}
}
+
+ if (!clear_soft_references_) {
+ if (!generational_) {
+ // If non-generational, always clear soft references.
+ clear_soft_references_ = true;
+ } else {
+ // If generational, clear soft references if a whole heap collection.
+ if (whole_heap_collection_) {
+ clear_soft_references_ = true;
+ }
+ }
+ }
+
Locks::mutator_lock_->AssertExclusiveHeld(self_);
TimingLogger::ScopedSplit split("MarkingPhase", &timings_);
@@ -762,18 +783,34 @@
if (generational_) {
// Decide whether to do a whole heap collection or a bump pointer
// only space collection at the next collection by updating
- // whole_heap_collection. Enable whole_heap_collection once every
- // kDefaultWholeHeapCollectionInterval collections.
+ // whole_heap_collection.
if (!whole_heap_collection_) {
- --whole_heap_collection_interval_counter_;
- DCHECK_GE(whole_heap_collection_interval_counter_, 0);
- if (whole_heap_collection_interval_counter_ == 0) {
- whole_heap_collection_ = true;
+ if (!kUseBytesPromoted) {
+ // Enable whole_heap_collection once every
+ // kDefaultWholeHeapCollectionInterval collections.
+ --whole_heap_collection_interval_counter_;
+ DCHECK_GE(whole_heap_collection_interval_counter_, 0);
+ if (whole_heap_collection_interval_counter_ == 0) {
+ whole_heap_collection_ = true;
+ }
+ } else {
+ // Enable whole_heap_collection if the bytes promoted since
+ // the last whole heap collection exceeds a threshold.
+ bytes_promoted_since_last_whole_heap_collection_ += bytes_promoted_;
+ if (bytes_promoted_since_last_whole_heap_collection_ >= kBytesPromotedThreshold) {
+ whole_heap_collection_ = true;
+ }
}
} else {
- DCHECK_EQ(whole_heap_collection_interval_counter_, 0);
- whole_heap_collection_interval_counter_ = kDefaultWholeHeapCollectionInterval;
- whole_heap_collection_ = false;
+ if (!kUseBytesPromoted) {
+ DCHECK_EQ(whole_heap_collection_interval_counter_, 0);
+ whole_heap_collection_interval_counter_ = kDefaultWholeHeapCollectionInterval;
+ whole_heap_collection_ = false;
+ } else {
+ // Reset it.
+ bytes_promoted_since_last_whole_heap_collection_ = bytes_promoted_;
+ whole_heap_collection_ = false;
+ }
}
}
// Clear all of the spaces' mark bitmaps.