diff --git a/tl-tester b/tl-tester
index 7fe877ea..1b12e210 100755
--- a/tl-tester
+++ b/tl-tester
@@ -117,7 +117,7 @@ $WRAP ./toplev.py -o /dev/null --no-desc -v -l5 --run-sample $LOAD
 for cpu in $ALLCPUS ; do
 EVENTMAP=${cpus[$cpu]} FORCECPU=$cpu $WRAP ./toplev.py -o /dev/null --no-desc -v --all --show-sample $LOAD >&log
 cat log
-grep "not found" log && exit 1
+grep -v UNC log | grep "not found" && exit 1
 done
 
 trap "" ERR 0
diff --git a/toplev.py b/toplev.py
index 923b3257..b18c2c5b 100755
--- a/toplev.py
+++ b/toplev.py
@@ -676,9 +676,15 @@ def separator(x):
         return ""
     return ":"
 
+def add_filter_event(e):
+    s = separator(e)
+    if not e.endswith(s + ring_filter):
+        return e + s + ring_filter
+    return e
+
 def add_filter(s):
     if ring_filter:
-        s = [x + separator(x) + ring_filter for x in s]
+        s = map(add_filter_event, s)
     return s
 
 def raw_event(i, name="", period=False):