diff -r c093cc6e6c99 -r 313e3a279828 contrib/perf.py
--- a/contrib/perf.py	Thu Nov 07 03:59:22 2019 -0800
+++ b/contrib/perf.py	Thu Nov 07 13:18:19 2019 -0500
@@ -1658,7 +1658,7 @@
             )
         else:
             os.environ[r'HGRCPATH'] = r' '
-            os.system(r"%s version -q > NUL" % sys.argv[0])
+            os.system("%s version -q > NUL" % sys.argv[0])
 
     timer(d)
     fm.end()