ps_background.md

## [分布式训练概述](https://www.paddlepaddle.org.cn/tutorials/projectdetail/459124)


## [多机多卡训练](https://www.paddlepaddle.org.cn/tutorials/projectdetail/459127)


## [参数服务器训练](https://www.paddlepaddle.org.cn/tutorials/projectdetail/464839)