* fuse all_reduce
test=develop

* add fuse_parameter_groups_size
test=develop

* Polish code
test=develop

* Fix travis-ci
test=develop

* Add SetGroupAccordingToLayers and SetGroupAccordingToGroupSize
test=develop

* Add SetGroupAccordingToMemorySize
test=develop

* fix multi_devices_graph
test=develop

* reset params_grads
test=develop

* Polish code
test=develop

test=develop

* remove concast_cast and refactor code test=develop

* reduce flag use test=develop

* add ir memory optimize test case for IfElse op, test=develop

* fix some unitttest failure by force using the python memory_optimize, test=develop

* tweak comments, test=develop

* fix unittest, test=develop

* fix unittest, test=develop

* add ir memory optimize test case for IfElse op, test=develop

* fix some unitttest failure by force using the python memory_optimize, test=develop

* tweak comments, test=develop

* fix unittest, test=develop

* fix unittest, test=develop

test=develop

test=develop

* refine profiler && add runtime tracer

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* test=develop

* fix bug && test=develop

* add thread id map && test=develop

* test=develop

* testing

* bug fix

* remove cuda event && refine code && test=develop

* test=develop

* test=develop

* test=develop

* fix windows temp file && test=develop

* test=develop

* fix windows bug && test=develop

* fix start up issue && test=develop

* code polish &&  test=develop

* remove unused code && test=develop

* add some cupti cbid && test=develop

* add FLAGS_multiple_of_cupti_buffer_size && test=develop

* fix compile error && test=develop

* add keyword && test=develop

* fix && test=develop

* code polish && test=develop

* add launch mp distributed mode module test=develop

* delete unused file test=develop

* refine usage test=develop

* refine usage test=develop

* move distributed package test=develop

* add to whl package test=develop

test=develop

test=develop

test=develop
This reverts commit 358e657f.

test=develop
This reverts commit 064512aa.

* remove workspace_handle in conv2d_cudnn
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* remove workspace_handle
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* fix bug
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* make test_conv2d_op SERIAL
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* save memory in conv_cudnn
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* enhance thread safety
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* enhance temporary allocator
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* Add excess fraction
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* follow comments
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* fix bug and code refine
test=develop

* fix memory size check
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* rename reuse_tmp_allocation_excess_fraction
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test=develop

Since conv_fusion_op is not exposed into Python, remote the env flag in __init__.py
test=develop

test=develop

* Inception fusion operator.
* Support horizontal layer fusion in conv_fusion_op.
* Search conv algo strategy for variable-length input.
   search N times and cache the searched algos. For other input, choose the algo of input whose area is closest to this input.

add module cleanup
test=develop

test=develop

test=develop

* follow comments. test=develop

* Fix typo

* fix compile error. test=develop

* merge develop branch. test=develop

* Remove set_equal

* Polish code

* Delete unused functions

test=develop

* polish code. test=develop

* follow comment

* polish code.

* fix windows compile error. test=develop

* fix op handle.

* rerun ci. test=develop

* rerun ci. test=develop

* rerun macci. test=develop

* polish code. test=develop

* rewrite sort code. test=develop

* remove unused code. test=develop

* fix tests. test=develop

* fix conflict. test=develop

* follow comment. test=develop

* merge develop branch. test=develop

* fix tests. test=develop

* remove ToTypeIndex. test=develop

* rerun ci. test=develop

test=develop

Revert "Merge pull request #14798 from PaddlePaddle/revert-14786-revert-14782-revert-14398-imperative"

This reverts commit b1d3a1c8, reversing
changes made to f1fb64b1.