* fix flake8 CodeStyle E266

* fix comments

* [CodeStyle][py2][U004] unecessary explicit `object` inheritance in class definition

* fix an increment

* [CodeStyle][py2] remove `six` package (part2)

* six.ensure_str

* remove unused `import six`

* remove six from BUILTIN_LIKELY_MODULES

* remove six in example code

* remove some decode

* try to fix example code

* fix MockEtcdClient get/get_prefix returns data type

* fix MockEtcdClient get_prefix returns data

* fix MockEtcdClient get returns data

* remove `six` in pypi and conda requirements

* fix MockEtcdClient add_watch_callback/add_watch_prefix_callback returns data type

* refine MockEtcdClient

* update config

* re-blacken python code

* temporarily disable date and diff_py_file

* skip a format

* add rpc module in cpp side

* add rpc module in python side

* support win32 and mac for rpc

* 代码优化

* 优化代码

* update rpc

* update rpc launch

* rpc remove rank and world_size api

* fix logger import bug

* remove support for win and mac

* remove support for xpu, npu, cinn and rocm

* remove support for xpu, npu, cinn and rocm

* fix shutdown barrier timeout bug

* update:python_rpc_handler to shared ptr

* fix master shutodwn first bug

* tests support for cpu

* update log to vlog

* update get service info api

* add single process test case

* remove process group

* remove some useless dependencies

* update rpc api comments

* update rpc comments: Example to Examples

* update rpc api comments

* update rpc api comments

* update launch api comments

* update init_rpc comments

* update rpc sync and async comments

* fix bug: init_rpc cant be called repeatly in a process

* update rpc api comment: make master endpoint unique

* update rpc api:service to worker, timeout_ms to timeout

* rename ServiceInfo to WorkerInfo

* refactor: rename server to worker, log to vlog

* add launch test

* remove unused codes

* refine

* [CodeStyle][F401] remove unused import in python/paddle/distributed

* remove pass

* empty commit

* Fix ValueError: list.remove(x): x not in list for meta_optimizer_names.

Fix ValueError: list.remove(x): x not in list for meta_optimizer_names.

* Fix split import.

Fix split import.

* add noqa after meta_optimizers in factory

* restort collective ops

* expand `import *`

* add noqa after required imports

* try to fix APIs without core.ops

* Revert "try to fix APIs without core.ops"

This reverts commit 6172beaf601e84bf61f2490c12c4739f0edaa5eb.

* fix an increment

* empty commit

* add noqa after required imports

* expand `import *`, fix ci error
Co-authored-by: NShuangchi He <34329208+Yulv-git@users.noreply.github.com>

* make launch compatible

* fix ut

* fix log offset

* [CustomDevice] add custom ccl 2/2

* update

* update

* update launch

* add launch test

* launch test for cpu

* bs 1

* update paddle.distributed.launch

* add sample code

* update shell

* fix typo

* fix typo

* update docs

* rm code

* fix doc 2

* fix doc 3

* fix doc 4
Co-authored-by: Nroot <root@sgjur-pod004-1.ipu.graphcore.cn>

* use yapf to format all python file

* yapf exclude two unittests file for they rely on writing and reading file, and format will break them

* disable diff_py_file because too many diff files cause command following failed

This reverts commit e680d581.

* [IPU] support paddle.distributed.launch with IPUs

* add device_num to env_args_mapping

* add nvsmi

* collect gpu info to log

* fix unitest

* rm ret_type