* elastic unitest

* rename demo

* del py2 code2

* fix test timeout

* elastic etcd ready

* add pplayer

* add sharedlayerdesc

* update, test=develop

* add parallel_cross_entropy

* add grad for crossentropy

* fix cross entropy

* modify API nn.Bilinear's doc, test=develop

* fix c_split bug

* fix utest

* add c_embedding for tensorparallel

* Dygraph Recompute support AMP

* dygraph recompute: update unitest

* support ssd in PsCore

* remove log

* remove bz2

* defalut value

* code style

* parse table class

* code style

* add define

* add async save for sparse table
* add load profiler for sparse table
* add load info for sparse table

* fix pipeline

* fix mp pp dp

* fix utest of hybrid parallel

* add utest for tuple

* fix precision of mp

* fix bug of seed

* fix dp

* print group

* fix cpp lint
* fix save/load with unexpected value
* fix save and user interface

* fix find_unused_parameters default value

* add trainprofiler for heterps in oneps; test=develop

* add set_use_ps_gpu; test=develop

* add raw program, test=develop

* update, test=develop

avoid polluting logging's root logger

* Revert "Revert "[PsCore] optimize performance of large kv (#32535)" (#32599)"

This reverts commit 809ac036.

* brpc dep

* fixed docs.

* Fixed docs. test=document_fix

code bak.

fixed docs. test=document_fix

* Revert to previous version of python/paddle/fluid/backward.py

* fixed bugs.

* test=document_fix. Fixed examples.