[vm] Reset vm isolate symbol table load factor

runtime/vm/symbols.cc

 // Copyright (c) 2012, 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/symbols.h"
 
 #include "vm/handles.h"
 #include "vm/hash_table.h"
 #include "vm/isolate.h"
 #include "vm/object.h"
@@ skipping 318 matching lines @@
 
   SymbolTable::Iterator iter(&table);
   while (iter.MoveNext()) {
     symbol ^= table.GetKey(iter.Current());
     ASSERT(!symbol.IsNull());
     bool present = unified_table.Insert(symbol);
     ASSERT(!present);
   }
   table.Release();
 
-  const double kMinLoad = 0.90;
-  const double kMaxLoad = 0.90;
-  HashTables::EnsureLoadFactor(kMinLoad, kMaxLoad, unified_table);
+  // TODO(30378): The default load factor of 0.75 / 2 burns ~100KB, but
+  // increasing the load factor regresses Flutter's hot restart time.
+  // const double kMinLoad = 0.90;
+  // const double kMaxLoad = 0.90;
+  // HashTables::EnsureLoadFactor(kMinLoad, kMaxLoad, unified_table);
 
   return unified_table.Release().raw();
 }
 
 void Symbols::Compact(Isolate* isolate) {
   ASSERT(isolate != Dart::vm_isolate());
   Zone* zone = Thread::Current()->zone();
 
   // 1. Drop the symbol table and do a full garbage collection.
   isolate->object_store()->set_symbol_table(Object::empty_array());
@@ skipping 345 matching lines @@
 RawObject* Symbols::GetPredefinedSymbol(intptr_t object_id) {
   ASSERT(IsPredefinedSymbolId(object_id));
   intptr_t i = (object_id - kMaxPredefinedObjectIds);
   if ((i > kIllegal) && (i < Symbols::kMaxPredefinedId)) {
     return symbol_handles_[i]->raw();
   }
   return Object::null();
 }
 
 }  // namespace dart