diff --git a/trunk/src/core/srs_core_performance.hpp b/trunk/src/core/srs_core_performance.hpp
index c1b924756..07a1e57af 100644
--- a/trunk/src/core/srs_core_performance.hpp
+++ b/trunk/src/core/srs_core_performance.hpp
@@ -192,8 +192,8 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  * whether enable the special memory watcher.
  * which used for memory leak debug and hurts performance.
  */
-#define SRS_MEM_WATCH
 #undef SRS_MEM_WATCH
+#define SRS_MEM_WATCH
 
 #endif