diff -r bf728e72a219 -r 954489932c4f mercurial/worker.py
--- a/mercurial/worker.py	Thu May 11 13:59:48 2017 -0700
+++ b/mercurial/worker.py	Wed May 31 23:42:58 2017 +0530
@@ -26,7 +26,7 @@
 
     # posix
     try:
-        n = int(os.sysconf('SC_NPROCESSORS_ONLN'))
+        n = int(os.sysconf(r'SC_NPROCESSORS_ONLN'))
         if n > 0:
             return n
     except (AttributeError, ValueError):