--- a/mercurial/dispatch.py	Tue Mar 15 00:14:53 2016 +0900
+++ b/mercurial/dispatch.py	Mon Mar 14 11:06:34 2016 +0000
@@ -129,6 +129,7 @@
         ret = -1
     finally:
         duration = time.time() - starttime
+        req.ui.flush()
         req.ui.log("commandfinish", "%s exited %s after %0.2f seconds\n",
                    msg, ret or 0, duration)
     return ret