转载：
https://www.cnblogs.com/fnng/archive/2012/06/09/2543274.html
https://blog.csdn.net/jiulanhao/article/details/88573506
https://blog.csdn.net/qq_40140519/article/details/88188290
性能常见分类
原文：https://www.cnblogs.com/shengyin/p/12826348.html
