diff --git a/contrib/revsetbenchmarks.py b/contrib/revsetbenchmarks.py
--- a/contrib/revsetbenchmarks.py
+++ b/contrib/revsetbenchmarks.py
@@ -94,7 +94,7 @@ revsetsfile = sys.stdin
 if options.file:
     revsetsfile = open(options.file)
 
-revsets = [l.strip() for l in revsetsfile]
+revsets = [l.strip() for l in revsetsfile if not l.startswith('#')]
 
 print "Revsets to benchmark"
 print "----------------------------"
diff --git a/contrib/revsetbenchmarks.txt b/contrib/revsetbenchmarks.txt
--- a/contrib/revsetbenchmarks.txt
+++ b/contrib/revsetbenchmarks.txt
@@ -14,7 +14,9 @@ max(tip:0)
 min(0:tip)
 0::
 min(0::)
+# those two `roots(...)` inputs are close to what phase movement use.
 roots((tip~100::) - (tip~100::tip))
+roots((0::) - (0::tip))
 ::p1(p1(tip))::
 public()
 :10000 and public()
@@ -23,7 +25,6 @@ draft()
 max(::(tip~20) - obsolete())
 roots((0:tip)::)
 (not public() - obsolete())
-roots((0::) - (0::tip))
 (_intlist('20000\x0020001')) and merge()
 parents(20000)
 (20000::) - (20000)