diff --git a/contrib/revsetbenchmarks.txt b/contrib/revsetbenchmarks.txt
--- a/contrib/revsetbenchmarks.txt
+++ b/contrib/revsetbenchmarks.txt
@@ -20,3 +20,4 @@ public()
 :10000 and public()
 draft()
 :10000 and draft()
+max(::(tip~20) - obsolete())