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[feature] Add clip_grad_norm for hybrid_parallel_plugin (#4837)
* Add clip_grad_norm for hibrid_parallel_plugin * polish code * add unittests * Move tp to a higher-level optimizer interface. * bug fix * polish code
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@@ -3,9 +3,7 @@ from typing import Optional
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import torch
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import torch.distributed as dist
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from torch import Tensor, inf
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from torch._utils import _flatten_dense_tensors, _unflatten_dense_tensors
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from torch.distributed import ProcessGroup
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def flatten(input_):
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@@ -192,53 +190,6 @@ def calculate_global_norm_from_list(norm_list):
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total_norm += norm**2.0
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return math.sqrt(total_norm)
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def compute_norm(gradients: Tensor, dp_group: ProcessGroup, tp_group: ProcessGroup, norm_type: int = 2) -> int:
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"""Clips gradient norm of an iterable of parameters.
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This is adapted from torch.nn.utils.clip_grad.clip_grad_norm_ and
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added functionality to handle model parallel parameters.
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Args:
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gradients (Tensor): The gradients to compute norm
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dp_group (ProcessGroup): The process group of ZeRO Data Parallelism
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tp_group (ProcessGroup): The process group of Tensor Parallelism
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norm_type (int, optional): type of the used p-norm, Can be ``'inf'`` for infinity norm. Defaults to 2.
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Returns:
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int: The total norm of given gradients
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"""
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norm_type = float(norm_type)
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if norm_type == inf:
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total_norm = max(g.data.abs().max() for g in gradients)
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total_norm_cuda = torch.cuda.FloatTensor([float(total_norm)])
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dist.all_reduce(total_norm_cuda, op=torch.distributed.ReduceOp.MAX, group=dp_group)
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# Take max across all GPUs.
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if tp_group is not None:
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dist.all_reduce(tensor=total_norm_cuda, op=torch.distributed.ReduceOp.MAX)
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total_norm = total_norm_cuda[0].item()
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else:
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total_norm = 0.0
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for g in gradients:
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param_norm = g.data.double().norm(norm_type)
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total_norm += param_norm.item() ** norm_type
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# Sum across all model parallel GPUs.
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total_norm_cuda = torch.cuda.FloatTensor([float(total_norm)])
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torch.distributed.all_reduce(total_norm_cuda, op=torch.distributed.ReduceOp.SUM, group=dp_group)
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if tp_group is not None:
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dist.all_reduce(tensor=total_norm_cuda, op=torch.distributed.ReduceOp.SUM, group=tp_group)
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total_norm = total_norm_cuda[0].item() ** (1.0 / norm_type)
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if total_norm == float("inf") or total_norm == -float("inf") or total_norm != total_norm:
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total_norm = -1
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return total_norm
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def sync_tensor(flat_tensor, tensor_list):
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"""
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Synchronize the flattened tensor and unflattened tensor list. When
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