[Auto Parallel] Add general gradient merge pass to support auto parallel #38259
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| # Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved. | |||
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Please rename gradient_merge.py to auto_parallel_gradient_merge.py since this pass may not work for other codes.
| return optimize_ops_desc | ||
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| def _remove_op_role_var(param, grad): |
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What is the purpose of _remove_op_role_var?
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非自动并行的情况下，多卡训练时，是通过“op_role_var”这一变量来记录通信的Var（标记哪些是需要通信的梯度），增加grad merge后，原op中记录的op_role_var是错误的，需要删除，同时相应的optimizer op需要增加相应op_role_var，便于后续对grad进行allreduce merge
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给op_role_var 添加allreduce 是PE的逻辑，自动并行不走PE， 是通过每个dist op 自己判断是否需要梯度同步 和同步的dp world （可能存在多个dp world 的情况）。op_role_var 在自动并行是不生效的（因为无法区分多个 dp world 的情况）。所以都不需要添加
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已将program中的op_role_var参数删除
| _add_gm_op_role_var(new_grad_op, param, gradient_merge_var, | ||
| cond_var_name) | ||
| new_params_grads.append([param, gradient_merge_var]) | ||
| return new_params_grads, param_to_gradient_merge |
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It is better to rename new_params_grads to new_params_to_grads as param_to_gradient_merge to explicitly indicate a dict.
xymyeah changed the title xymyeah changed the title 
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[Auto Parallel] add gradient merge pass
Refer to for the results of precision alignment : https://github.com/xymyeah/gradient_merge_precision_alignment