Don't track allocations in product mode.

runtime/vm/gc_marker.cc

 // Copyright (c) 2011, 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/gc_marker.h"
 
 #include "vm/allocation.h"
 #include "vm/dart_api_state.h"
 #include "vm/isolate.h"
 #include "vm/log.h"
@@ skipping 648 matching lines @@
   const intptr_t task_index_;
   const intptr_t num_tasks_;
   uintptr_t* num_busy_;
 
   DISALLOW_COPY_AND_ASSIGN(MarkTask);
 };
 
 
 template<class MarkingVisitorType>
 void GCMarker::FinalizeResultsFrom(MarkingVisitorType* visitor) {
+#ifndef PRODUCT
   {
     MutexLocker ml(&stats_mutex_);
     marked_bytes_ += visitor->marked_bytes();
     // Class heap stats are not themselves thread-safe yet, so we update the
     // stats while holding stats_mutex_.
     ClassTable* table = heap_->isolate()->class_table();
     for (intptr_t i = 0; i < table->NumCids(); ++i) {
       const intptr_t count = visitor->live_count(i);
       if (count > 0) {
         const intptr_t size = visitor->live_size(i);
         table->UpdateLiveOld(i, size, count);
       }
     }
   }
+#endif  // !PRODUCT
   visitor->Finalize();
 }
 
 
 void GCMarker::MarkObjects(Isolate* isolate,
                            PageSpace* page_space,
                            bool invoke_api_callbacks,
                            bool collect_code) {
   Prologue(isolate, invoke_api_callbacks);
   // The API prologue/epilogue may create/destroy zones, so we must not
@@ skipping 82 matching lines @@
       // Phase 3: Finalize results from all markers (detach code, etc.).
       barrier.Exit();
     }
     ProcessWeakTables(page_space);
     ProcessObjectIdTable(isolate);
   }
   Epilogue(isolate, invoke_api_callbacks);
 }
 
 }  // namespace dart