* delete empty line of pybing.cc, test=develop

* use nvtx push pop in timeline, test=develop

* change year, test=develop

* add #ifdef PADDLE_WITH_CUDA, test=develop

* add #ifndef WIN32, test=develop

* is_pushed to is_pushed_, test=develop

* rename sendrecv.proto to namespace paddle.distributed

* split ps with distributed

* oneps (3/4)
Co-authored-by: NMrChengmo <cmchengmo@163.com>
Co-authored-by: Nmalin10 <malin10@baidu.com>
Co-authored-by: Nchengmo <chengmo@baidu.com>

* 　add heter box

* add trainer, worker, wrapper...

* format

* for ci

* format

* remove boost get

* boost & copyright

* rename

* 　rename

* format

* format

* format
Co-authored-by: Nyaoxuefeng6 <yaoxuefeng@baidu.com>

* enhance array_to_lod_tensor_op lod_tensor_to_array_op errors information. test=develop

* fix format. test=develop

* format fix. test=develop

* add lod_rank_table. test=develop

* fix format. test=develop

* fix doc info. test=develop

* fix np error

* add unbind dygraph api. test=develop

* fix unbind doc.test=develop

* basic impl of type promote

* add comment & another testcase

* fix complex bugs & support python op promote type

* fix failed unittests & polish code

* add unittest for coverage

* change to only promote complex type

* polish code details

* polish several comments

* add broadcast_shape api

* add ut

* follow comments

* add example code, test=dodument_fix

* update example code, test=document_fix

* add fuse_bn_add_act pass

* support setting xpu place

* add ut, test=kunlun

* add sumary feature

* refine printting tensor

* add sci_mode

* add sample code

* fix indent error

* fix _format_item

* polish code

* support item indent

* add ut

* set place for ut

* fix py2 issue

* fix ut

* Add avx instructions check

* Small fix

* Change function name

* Change uint to unsigned int

* polish BuildStrategy api doc & example

* polish ExecutionStrategy api doc & example

* polish details

* add paddle.fluid._cuda_synchronize, test=develop

* fix bug about core_avx core_noavx, test=develop

* delete CPUPlace and XPUPlace, test=develop

* support use add instead of sum to do gradient accumulation

* add inplace addto pass

* add grad_add op and inplace addto pass

* remove debug code

* code refine

* fix bug when sereral sum ops inserts at same op_idx

* fix Flags type

* add addto attribute for conv3d

* fix ut

* code clean

* fix type

add collective op for cpu using gloo and paddle.distributed.* apis

* support Baidu AI Accelerator
  * test=kunlun

* minor
 * test=kunlun

* support xpu op in separate file
 * test=kunlun

* update XPU error message and remove duplicated code

 * test=kunlun

* minor
 * test=kunlun

* minor
 * test=kunlun

* expose and unify the Tensor concepts to the user

* expose tensor to user

* add copy place for Tensor

* add copy place for Tensor

* add note

* add macro PADDLE_WITH_CUDA

* remove RUN_TYPE=DIST

* fix some error

* fix loaded var suffix repeat error

* use new dygraph name for loaded param

* add heter ps mode

* code style
test=develop

* add with_pslib
test=develop

* unitest
test=develop

* code style
test=develop

* code style
test=develop

* code style
test=develop

* code style
test=develop

* code style
test=develop

* code style
test=develop

* code style
test=develop

* code style
test=develop

* test monitor
test=develop

* prepare trainer
test=develop

* code style
test=develop

Integrated Trainer of Parameter Server (API add `fluid.contrib.layers.sparse_embedding` only) (#22957)

* Integrated Trainer of Parameter Server

* Add a StatValue class in the backend to represent a stat.
* Add a singleton StatRegistry to maintain the collection of stats.
* For the sake of code neatness, we only support type of int and float, which can cover most of the scenarios.

* refine err_msg of pybind.cc, test=develop

* refine err_msg in tensor_py.h, test=develop

* refine error msg, test=develop

* fix test_exception, test=develop

* follow comments, test=develop