--- a/contrib/perf.py	Tue Aug 23 23:47:59 2016 +0200
+++ b/contrib/perf.py	Thu Aug 11 14:51:19 2016 +0200
@@ -575,8 +575,8 @@
         s.fncache._dirty = True
         s.fncache.write(tr)
     timer(d)
+    tr.close()
     lock.release()
-    tr.close()
     fm.end()
 
 @command('perffncacheencode', formatteropts)