--- a/contrib/perf.py	Sun Dec 27 23:55:54 2015 +0900
+++ b/contrib/perf.py	Sun Dec 27 23:55:54 2015 +0900
@@ -441,6 +441,7 @@
         s.fncache.write(tr)
     timer(d)
     lock.release()
+    tr.close()
     fm.end()
 
 @command('perffncacheencode', formatteropts)