readthedocs fix

Author: yinhaofeng

doc/benchmark.md

@@ -2,12 +2,8 @@
 
 `PaddleRec`中各模型在各种模式下的效果及性能数据将随版本迭代不断更新，欢迎持续关注并监督，如有任何问题，欢迎在[Github Issue](https://github.com/PaddlePaddle/PaddleRec/issues)提出。
 
-## [召回模型介绍及Benchmark](../models/recall/readme.md)
+## [Benchmark CtrDnn](https://github.com/PaddlePaddle/Perf/tree/master/CtrDnn)
 
-## [排序模型介绍及Benchmark](../models/rank/readme.md)
+## [Benchmark Wide&Deep](https://github.com/PaddlePaddle/Perf/tree/master/WideDeep)
 
-## [内容理解模型介绍及Benchmark](../models/contentunderstanding/readme.md)
-
-## [多任务模型介绍及Benchmark](../models/multitask/readme.md)
-
-## [树模型介绍及Benchamrk](../models/treebased/README.md)
+## [Benchmark Word2Vec](https://github.com/PaddlePaddle/Perf/tree/master/Word2Vec)