From a78184f90c21e3b2d288891e243c111f8091c3d4 Mon Sep 17 00:00:00 2001
From: WEI Zhicheng <zhicheng@opensourceforge.net>
Date: Wed, 6 Aug 2014 18:35:24 +0800
Subject: [PATCH] Fix `PeriodicCallback' when callback function return `Future'
 and has `Exception' will silence ignore

---
 tornado/ioloop.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tornado/ioloop.py b/tornado/ioloop.py
index 738cc964..e15252d3 100644
--- a/tornado/ioloop.py
+++ b/tornado/ioloop.py
@@ -969,10 +969,11 @@ class PeriodicCallback(object):
         if not self._running:
             return
         try:
-            self.callback()
+            return self.callback()
         except Exception:
             self.io_loop.handle_callback_exception(self.callback)
-        self._schedule_next()
+        finally:
+            self._schedule_next()
 
     def _schedule_next(self):
         if self._running: