--- a/bench.py	Sun Aug 07 12:59:40 2016 +0800
+++ b/bench.py	Sun Aug 07 13:03:34 2016 +0800
@@ -1,4 +1,5 @@
 #!/usr/bin/env python
+import atexit
 import errno
 import logging
 import os
@@ -295,17 +296,17 @@
     else:
         names = args.marks.split(',')
         marks = OrderedDict((k, v) for k, v in MARKS.items() if k in names)
+
     lockfd = lock(LOCKFILE)
-    try:
-        dbinit()
-        if args.auto:
-            if args.retry:
-                args.revsets = guessspikes(args.auto, marks)
-            else:
-                args.revsets = guessnew(args.auto, marks)
-        dbupdate(args.revsets, marks, args.mintime, args.mintries, args.retry)
-    finally:
-        unlock(lockfd, LOCKFILE)
+    atexit.register(unlock, lockfd, LOCKFILE)
+
+    dbinit()
+    if args.auto:
+        if args.retry:
+            args.revsets = guessspikes(args.auto, marks)
+        else:
+            args.revsets = guessnew(args.auto, marks)
+    dbupdate(args.revsets, marks, args.mintime, args.mintries, args.retry)
 
 
 if __name__ == '__main__':