diff --git a/src/main/vm/memory/heap.cpp b/src/main/vm/memory/heap.cpp
index 53889b8c4f0b7a74cf8fd7e975e4785e07acd192..83b3f1b89576eea9e8b2d6858b98bfded3647918 100644
--- a/src/main/vm/memory/heap.cpp
+++ b/src/main/vm/memory/heap.cpp
@@ -117,6 +117,7 @@ void* Space::allocate(size_t size) {
     char* start = _top;
     _top       += size;
     _capacity  -= size;
+    _rate       = _capacity * 1.0 / _size;
     //printf("after allocate %lx, _top is %p\n", size, _top);
     return start;
 }
diff --git a/src/main/vm/memory/heap.hpp b/src/main/vm/memory/heap.hpp
index 2e9a32de4031ae12c546ff305a5dc3c304fb0f87..e408742170608a7d2f96220c3e1dba4313863d07 100644
--- a/src/main/vm/memory/heap.hpp
+++ b/src/main/vm/memory/heap.hpp
@@ -13,6 +13,7 @@ private:
     char*  _end;
     size_t _size;
     size_t _capacity;
+    double _rate;
 
     Space(size_t size);
     ~Space();
@@ -22,6 +23,7 @@ public:
     void clear();
     bool can_alloc(size_t size);
     bool has_obj(char* obj);
+    double rate()  { return _rate; }
 };
 
 class Heap {
@@ -46,6 +48,7 @@ public:
     void* allocate(size_t size);
     void* allocate_meta(size_t size);
     void copy_live_objects();
+    double rate() { return eden->rate(); }
 
     void gc();
 };
diff --git a/src/main/vm/runtime/interpreter.cpp b/src/main/vm/runtime/interpreter.cpp
index 70c38540613f70c237da0a2c26c1e780843a383b..722c6e438acdd6fb33cc469fd4d5b9ba0ef88ccb 100644
--- a/src/main/vm/runtime/interpreter.cpp
+++ b/src/main/vm/runtime/interpreter.cpp
@@ -238,6 +238,10 @@ void Interpreter::eval_frame() {
 
         //printf("%d %d\n", op_code, op_arg);
 
+        if (Universe::heap->rate() < 0.05) {
+            Universe::heap->gc();
+        }
+
         switch (op_code) {
             case ByteCode::POP_TOP:
                 POP();