Zhuohan Li
7076fa1c9f
Refactor the tensor parallelism, quantization, and weight-loading codes. Summary of the new features enabled by this PR: - **All models** are able to be quantized with AWQ and SqueezeLLM, and [soon GPTQ](https://github.com/vllm-project/vllm/pull/1580). - Model loading code became much simpler. - Support model parallelism for all MQA/GQA models when the number of key/value heads is smaller than the tensor parallel size.
49 lines
1.6 KiB
Python
49 lines
1.6 KiB
Python
# Copyright 2023 The vLLM team.
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# Adapted from
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# https://github.com/NVIDIA/Megatron-LM/blob/main/megatron/core/tensor_parallel/utils.py
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# Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
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from typing import Sequence
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import torch
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def ensure_divisibility(numerator, denominator):
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"""Ensure that numerator is divisible by the denominator."""
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assert numerator % denominator == 0, "{} is not divisible by {}".format(
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numerator, denominator)
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def divide(numerator, denominator):
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"""Ensure that numerator is divisible by the denominator and return
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the division value."""
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ensure_divisibility(numerator, denominator)
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return numerator // denominator
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def split_tensor_along_last_dim(
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tensor: torch.Tensor,
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num_partitions: int,
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contiguous_split_chunks: bool = False,
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) -> Sequence[torch.Tensor]:
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""" Split a tensor along its last dimension.
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Arguments:
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tensor: input tensor.
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num_partitions: number of partitions to split the tensor
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contiguous_split_chunks: If True, make each chunk contiguous
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in memory.
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Returns:
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A list of Tensors
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"""
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# Get the size and dimension.
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last_dim = tensor.dim() - 1
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last_dim_size = divide(tensor.size()[last_dim], num_partitions)
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# Split.
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tensor_list = torch.split(tensor, last_dim_size, dim=last_dim)
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# NOTE: torch.split does not create contiguous tensors by default.
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if contiguous_split_chunks:
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return tuple(chunk.contiguous() for chunk in tensor_list)
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return tensor_list
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