一个简单的样例:
http://osedu.net/article/python/2014-03-18/501.html
ioloop的官方doc:
http://www.tornadoweb.org/en/stable/ioloop.html#tornado.ioloop.IOLoop
Tornado源码分析1:
http://amyangfei.me/2013/01/27/tornado-source-analysis-1/
Understanding the code inside Tornado, the asynchronous web server:
tornado实现异步计划任务及python常见计划任务方法:
http://www.tuicool.com/articles/QNvUf2
Tornado 之 IOLoop类分析: