--- a/contrib/perf.py	Sun Nov 25 22:39:54 2018 +0900
+++ b/contrib/perf.py	Fri Nov 23 02:11:11 2018 +0100
@@ -2251,6 +2251,9 @@
         repo = repoview.repoview(repo, filter)
     else:
         repo = repo.unfiltered()
+
+    repo.branchmap() # make sure we have a relevant, up to date branchmap
+
     # try once without timer, the filter may not be cached
     if branchmap.read(repo) is None:
         raise error.Abort(b'No branchmap cached for %s repo'