Add low memory mode option to ART.
Useful so that we match the option I added here:
https://googleplex-android-review.googlesource.com/#/c/328940/
In ART low memory mode reduces the maximum number of histogram
buckets. We also trim no matter the utilization.
Change-Id: I655ba63312c0a6574569cdd5171ca81ea338c2aa
diff --git a/runtime/base/timing_logger.cc b/runtime/base/timing_logger.cc
index e2d2d4c..b58b0ac 100644
--- a/runtime/base/timing_logger.cc
+++ b/runtime/base/timing_logger.cc
@@ -113,7 +113,8 @@
// Convert delta time to microseconds so that we don't overflow our counters.
delta_time /= kAdjust;
if (histograms_.size() <= index_) {
- histograms_.push_back(new Histogram<uint64_t>(label.c_str(), 50));
+ const size_t max_buckets = Runtime::Current()->GetHeap()->IsLowMemoryMode() ? 16 : 100;
+ histograms_.push_back(new Histogram<uint64_t>(label.c_str(), 50, max_buckets));
DCHECK_GT(histograms_.size(), index_);
}
histograms_[index_]->AddValue(delta_time);
diff --git a/runtime/gc/heap.cc b/runtime/gc/heap.cc
index 3cc60d9..47e9b75 100644
--- a/runtime/gc/heap.cc
+++ b/runtime/gc/heap.cc
@@ -68,12 +68,13 @@
const double Heap::kDefaultTargetUtilization = 0.5;
Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free,
- double target_utilization, size_t capacity,
- const std::string& original_image_file_name, bool concurrent_gc, size_t num_gc_threads)
+ double target_utilization, size_t capacity, const std::string& original_image_file_name,
+ bool concurrent_gc, size_t num_gc_threads, bool low_memory_mode)
: alloc_space_(NULL),
card_table_(NULL),
concurrent_gc_(concurrent_gc),
num_gc_threads_(num_gc_threads),
+ low_memory_mode_(low_memory_mode),
have_zygote_space_(false),
reference_queue_lock_(NULL),
is_gc_running_(false),
@@ -1855,9 +1856,9 @@
uint64_t ms_time = MilliTime();
float utilization =
static_cast<float>(alloc_space_->GetBytesAllocated()) / alloc_space_->Size();
- if ((utilization > 0.75f) || ((ms_time - last_trim_time_ms_) < 2 * 1000)) {
- // Don't bother trimming the alloc space if it's more than 75% utilized, or if a
- // heap trim occurred in the last two seconds.
+ if ((utilization > 0.75f && !IsLowMemoryMode()) || ((ms_time - last_trim_time_ms_) < 2 * 1000)) {
+ // Don't bother trimming the alloc space if it's more than 75% utilized and low memory mode is
+ // not enabled, or if a heap trim occurred in the last two seconds.
return;
}
diff --git a/runtime/gc/heap.h b/runtime/gc/heap.h
index 7615f98..3f91553 100644
--- a/runtime/gc/heap.h
+++ b/runtime/gc/heap.h
@@ -137,7 +137,7 @@
explicit Heap(size_t initial_size, size_t growth_limit, size_t min_free,
size_t max_free, double target_utilization, size_t capacity,
const std::string& original_image_file_name, bool concurrent_gc,
- size_t num_gc_threads);
+ size_t num_gc_threads, bool low_memory_mode);
~Heap();
@@ -276,6 +276,11 @@
verify_object_mode_ > kHeapVerificationNotPermitted;
}
+ // Returns true if low memory mode is enabled.
+ bool IsLowMemoryMode() const {
+ return low_memory_mode_;
+ }
+
void RecordFree(size_t freed_objects, size_t freed_bytes);
// Must be called if a field of an Object in the heap changes, and before any GC safe-point.
@@ -502,6 +507,9 @@
// How many GC threads we may use for garbage collection.
const bool num_gc_threads_;
+ // Boolean for if we are in low memory mode.
+ const bool low_memory_mode_;
+
// If we have a zygote space.
bool have_zygote_space_;
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index 485c636..5298181 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -341,6 +341,7 @@
// Default to number of processors minus one since the main GC thread also does work.
parsed->heap_gc_threads_ = sysconf(_SC_NPROCESSORS_CONF) - 1;
parsed->stack_size_ = 0; // 0 means default.
+ parsed->low_memory_mode_ = false;
parsed->is_compiler_ = false;
parsed->is_zygote_ = false;
@@ -488,6 +489,8 @@
return NULL;
}
parsed->stack_size_ = size;
+ } else if (option == "-XX:LowMemoryMode") {
+ parsed->low_memory_mode_ = true;
} else if (StartsWith(option, "-D")) {
parsed->properties_.push_back(option.substr(strlen("-D")));
} else if (StartsWith(option, "-Xjnitrace:")) {
@@ -835,7 +838,8 @@
options->heap_maximum_size_,
options->image_,
options->is_concurrent_gc_enabled_,
- options->heap_gc_threads_);
+ options->heap_gc_threads_,
+ options->low_memory_mode_);
BlockSignals();
InitPlatformSignalHandlers();
diff --git a/runtime/runtime.h b/runtime/runtime.h
index d480e36..47fff29 100644
--- a/runtime/runtime.h
+++ b/runtime/runtime.h
@@ -97,6 +97,7 @@
size_t heap_max_free_;
double heap_target_utilization_;
size_t stack_size_;
+ bool low_memory_mode_;
size_t lock_profiling_threshold_;
std::string stack_trace_file_;
bool method_trace_;
