Grow new gen (1M -> 4M -> 16M on 32-bit) when there is little garbage.

runtime/vm/dart.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/dart.h"
 
 #include "vm/code_observers.h"
 #include "vm/cpu.h"
 #include "vm/dart_api_state.h"
 #include "vm/dart_entry.h"
@@ skipping 12 matching lines @@
 #include "vm/snapshot.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 #include "vm/thread_interrupter.h"
 #include "vm/thread_pool.h"
 #include "vm/virtual_memory.h"
 #include "vm/zone.h"
 
 namespace dart {
 
-DEFINE_FLAG(int, new_gen_heap_size, 32, "new gen heap size in MB,"
-            "e.g: --new_gen_heap_size=64 allocates a 64MB new gen heap");
+DEFINE_FLAG(int, new_gen_semi_max_size, (kWordSize <= 4) ? 16 : 32,
+            "Max size of new gen semi space in MB");
 DEFINE_FLAG(int, old_gen_heap_size, Heap::kHeapSizeInMB,
-            "old gen heap size in MB,"
-            "e.g: --old_gen_heap_size=1024 allocates a 1024MB old gen heap");
+            "Max size of old gen heap size in MB,"
+            "e.g: --old_gen_heap_size=1024 allows up to 1024MB old gen heap");
 
 DECLARE_FLAG(bool, print_class_table);
 DECLARE_FLAG(bool, trace_isolates);
 
 Isolate* Dart::vm_isolate_ = NULL;
 ThreadPool* Dart::thread_pool_ = NULL;
 DebugInfo* Dart::pprof_symbol_generator_ = NULL;
 ReadOnlyHandles* Dart::predefined_handles_ = NULL;
 
 // An object visitor which will mark all visited objects. This is used to
@@ skipping 158 matching lines @@
 
 
 RawError* Dart::InitializeIsolate(const uint8_t* snapshot_buffer, void* data) {
   // Initialize the new isolate.
   Isolate* isolate = Isolate::Current();
   TIMERSCOPE(isolate, time_isolate_initialization);
   ASSERT(isolate != NULL);
   StackZone zone(isolate);
   HandleScope handle_scope(isolate);
   Heap::Init(isolate,
-             FLAG_new_gen_heap_size * MBInWords,
+             FLAG_new_gen_semi_max_size * MBInWords,
              FLAG_old_gen_heap_size * MBInWords);
   ObjectIdRing::Init(isolate);
   ObjectStore::Init(isolate);
 
   // Setup for profiling.
   Profiler::InitProfilingForIsolate(isolate);
 
   if (snapshot_buffer == NULL) {
     const Error& error = Error::Handle(Object::Init(isolate));
     if (!error.IsNull()) {
@@ skipping 73 matching lines @@
   return predefined_handles_->handles_.AllocateScopedHandle();
 }
 
 
 bool Dart::IsReadOnlyHandle(uword address) {
   ASSERT(predefined_handles_ != NULL);
   return predefined_handles_->handles_.IsValidScopedHandle(address);
 }
 
 }  // namespace dart