--- a/contrib/perf.py	Fri Jan 04 19:20:51 2013 +0100
+++ b/contrib/perf.py	Fri Jan 04 19:22:15 2013 +0100
@@ -261,8 +261,10 @@
 
     timer(d)
 
-@command('perfrevset')
+@command('perfrevset',[],
+         "REVSET")
 def perfrevset(ui, repo, expr):
+    """benchmark the execution time of a revset"""
     def d():
         repo.revs(expr)
     timer(d)