diff -r b3e24a9c5f9b -r 64cb281d23a5 contrib/perf.py
--- a/contrib/perf.py	Tue Nov 24 22:01:11 2015 +0000
+++ b/contrib/perf.py	Tue Nov 24 21:44:16 2015 +0000
@@ -239,8 +239,8 @@
     def d():
         # acceptremote is True because we don't want prompts in the middle of
         # our benchmark
-        merge.calculateupdates(repo, wctx, rctx, ancestor, False, False, False,
-                               acceptremote=True)
+        merge.calculateupdates(repo, wctx, rctx, [ancestor], False, False,
+                               False, acceptremote=True, followcopies=True)
     timer(d)
     fm.end()