--- a/contrib/perf.py	Sat Jul 18 14:16:07 2015 -0500
+++ b/contrib/perf.py	Sat Jul 18 14:16:36 2015 -0500
@@ -18,6 +18,7 @@
     place instead of duplicating it in all performance command."""
 
     # enforce an idle period before execution to counteract power management
+    # experimental config: perf.presleep
     time.sleep(ui.configint("perf", "presleep", 1))
 
     if opts is None: