* add fix op run order pass

* add ut for fix_op_run_order

* fix ci error

* improve coverage

* improve coverge again and fix cpu test case

* follow some comments

* Refine Constructor logic of ParallelExecutor

* Replace executor into ParallelExecutor in run_program_op

* refine error msg in var_handle.h, test=develop

* refine all_reduce_op_handle

* fix some error msg

* refine variable_visitor

* refine threaded_ssa_graph_executor

* refine inplace related files

* refine executor related files

* refine fetch_op_handle.cc

* fix bug

* follow comments

* optimized transformation form tensor to numpy, test=develop

* Modify fetch op handle, from memcpy Sync to memcpy Async, test=develop

* modify CUDAPinnedPlace to CPUPlace, test=develop

* modify CPUPlace to CUDAPinnedPlace, and set default inplace to false, test=develop

* revert fetch_op_handle, add fetch_async_op_handle, test=develop

* revert fetch_op_handle, add fetch_async_op_handle, test=develop

* fix error msg report, test=develop

* fix bug in cpuplace, test=develop

* fix bug in unmerge and tensorarray modle, test=develop

* fix bug, double copy gpu memory, test=develop

* fix chenweihang¡¯s review advice, test=develop

* polish pe exception process logic, test=develop

* fix unittest, test=develop

* add unittests, test=develop

* Support LoDTEnsorArray in fetch op

test=develop

* Support LoDTensorArray in fetch

test=develop

* Support LoDTensorArray in fetch

test=develop

* Support LoDTensorArray in fetch

test=develop

* Support LoDTensorArray in fetch

test=develop

* Support LoDTensorArray in fetch

test=develop

* Support LoDTensorArray in fetch

test=develop

* Support LoDTensorArray in fetch

test=develop

* Support LoDTensorArray in fetch

test=develop

* Support LoDTensorArray in fetch

test=develop

* solve the conflict of ops with the same name. test=develop

This reverts commit abe3e690.
test=develop

* solve the conflict of ops with the same name. test=develop

* update ScopeBufferedSSAGraphExecutor&AsyncSSAGraphExecutor&ThreadedSSAGraphExecutor&FastThreadedSSAGraphExecutor&ParallelSSAGraphExecutor&ParallelExecutor for fetching unmerged results.

* add the unit test for fetch_unmerged.

* update ut for multi-card and multi-cpu.

* add the error message and the user suggestion in FetchOpHandle. test=develop

* polish error message of parallel executor, test=develop

* change PADDLE_ENFORCE, test=develop

Add examples for error message writing specification - PreconditionNotMet, Unimplemented, Unavailable (#21137)

* add examples for error spec, test=develop

* change ENFORCE to ENFORCE_**, test=develop

test=develop

* feature/buffer_shared_inplace, test=develop

* refine code, test=develop

* fix elementwise_add op cpu inplace and sum inplace bug, test=develop

* add unittest and debug log, test=develop

* fix parallel_executor scope bug, polish code, test=develop

* fix sum op, activation op, single_in_place_inference bug, test=develop

* remove kLocalExecScopeName, test=develop

* fix unittest,test=develop

* fix out_var first version bug, test=develop

* follow comments,test=develop

* add event for fast executor and add threads for scopebuffer executor
test=develop

Refine the Executor when the num_thread=1

* speedup gc and inplace softmax_with_cross_entropy_grad
test=develop

* refine models gpu mem
Merge skip vars and warning messages of mem opt
remove relu mem opt
test=develop

* follow comments
test=develop

* Fix the bug of the fast threaded executor. I

* fix threaded executor bug
test=develop

* change the order of class member
test=develop

* Fix Travis CI
test=develop

* Unified ParallelExecutor and Compiler

* Unified ParallelExecutor and Compiler

test=develop

test=develop

Dry run tests will skip `Op.Run` and just perform job scheduling. It helps to analysis dead lock in PE.

test=develop

test=develop

test=develop

test=develop

It seems that the blocking queue might be destroyed early than Run
method complete. It might because the Run method throw some unhandled
exception. However, it should be shared_ptr when multthread access an
resource. So change BlockingQueue as a shared_ptr.

test=develop

    Node should be created by Graph::CreateXXX so that
    they are managed by graph.