diff --git a/synapse/util/logutils.py b/synapse/util/logutils.py
index c4dfb69c5..fd9ac4d4d 100644
--- a/synapse/util/logutils.py
+++ b/synapse/util/logutils.py
@@ -102,7 +102,7 @@ def time_function(f):
             _log_debug_as_f(
                 f,
                 "[FUNC START] {%s-%d}",
-                (func_name, _TIME_FUNC_ID),
+                (func_name, id),
             )
 
             r = f(*args, **kwargs)
@@ -111,7 +111,7 @@ def time_function(f):
             _log_debug_as_f(
                 f,
                 "[FUNC END] {%s-%d} %f",
-                (func_name, _TIME_FUNC_ID, end-start,),
+                (func_name, id, end-start,),
             )
 
         return r