vllm/vllm/lora/layers/column_parallel_linear.py
Jee Jee Li bb3eb80d92
[Core] Split LoRA layers (#24574)
Signed-off-by: Jee Jee Li <pandaleefree@gmail.com>
2025-09-10 07:47:51 -07:00

623 lines
23 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
from typing import Optional, Union, cast
import torch
import torch.nn as nn
from transformers import PretrainedConfig
from vllm.config import LoRAConfig
from vllm.distributed import (get_tensor_model_parallel_rank,
get_tensor_model_parallel_world_size,
tensor_model_parallel_all_gather)
from vllm.distributed.utils import divide
from vllm.model_executor.layers.linear import (ColumnParallelLinear,
MergedColumnParallelLinear,
QKVParallelLinear)
from vllm.platforms import current_platform
from .base_linear import BaseLinearLayerWithLoRA
from .utils import _fully_sharded_can_replace, _not_fully_sharded_can_replace
def _mcp_apply(x, bias, layer: "ColumnParallelLinearWithLoRA"):
"""
For `ColumnParallelLinearWithLoRA` or classes that inherit from
`ColumnParallelLinearWithLoRA`, they share the same `apply` logic.
"""
assert (layer.n_slices == len(layer.lora_a_stacked) == len(
layer.lora_b_stacked) == len(layer.output_slices))
if layer.lora_bias_stacked is not None:
assert layer.n_slices == len(layer.lora_bias_stacked)
output = layer.base_layer.quant_method.apply(layer.base_layer, x, bias)
x = x.view(-1, x.shape[-1])
output, out_orig_shape = output.view(-1, output.shape[-1]), output.shape
# Since communication is needed, the buffer is directly initialized as a
# tensor rather than a tuple of tensor.
buffers = torch.zeros(
(layer.n_slices, x.shape[0], layer.lora_a_stacked[0].shape[2]),
dtype=torch.float32,
device=x.device,
)
shrunk_buffers: Optional[torch.Tensor] = layer.punica_wrapper.add_shrink(
buffers, x, layer.lora_a_stacked, 1.0)
if not current_platform.can_update_inplace():
buffers = shrunk_buffers
buffers = tensor_model_parallel_all_gather(buffers)
lora_output: Optional[torch.Tensor] = layer.punica_wrapper.add_expand(
output,
buffers,
layer.lora_b_stacked,
layer.lora_bias_stacked,
layer.output_slices,
offset_start=0,
add_input=True)
if not current_platform.can_update_inplace():
output = lora_output
output = output.view(*out_orig_shape)
# now have column partitioned and packed output
return output
class ColumnParallelLinearWithLoRA(BaseLinearLayerWithLoRA):
"""
LoRA on top of ColumnParallelLinear layer.
LoRA B is sliced for tensor parallelism.
There are two types for the `base_layer`:
1. ColumnParallelLinear, e.g.`dense_h_to_4h` in `FalconForCausalLM`.
2. MergedColumnParallelLinear, e.g.`gate_up_proj` in `Phi3ForCausalLM`.
"""
def __init__(self, base_layer: ColumnParallelLinear) -> None:
super().__init__(base_layer)
# The base_layer type is ColumnParallelLinear or
# MergedColumnParallelLinear, their weight sharding logic is
# inconsistent when TP is greater than 1.
self.is_merged_col_linear = type(
base_layer) is MergedColumnParallelLinear
self.tp_size = get_tensor_model_parallel_world_size()
self.output_size = self.base_layer.output_size_per_partition
# There is only one LoRA layer
self.n_slices = 1
def slice_lora_a(self, lora_a: torch.Tensor) -> torch.Tensor:
return lora_a
def slice_lora_b(self, lora_b: torch.Tensor) -> torch.Tensor:
# Applicable to cases where the base_layer is
# MergedColumnParallelLinear.
if self.is_merged_col_linear:
tp_rank = get_tensor_model_parallel_rank()
shard_size = self.output_size // 2
offset = lora_b.shape[-1] // 2
left_weight = lora_b[:, tp_rank * shard_size:(tp_rank + 1) *
shard_size]
right_weight = lora_b[:, offset + tp_rank * shard_size:offset +
(tp_rank + 1) * shard_size]
lora_b = torch.cat([left_weight, right_weight], dim=1)
# Applicable to cases where the base_layer is
# ColumnParallelLinear.
else:
tensor_model_parallel_rank = get_tensor_model_parallel_rank()
shard_size = self.output_size
start_idx = tensor_model_parallel_rank * shard_size
end_idx = (tensor_model_parallel_rank + 1) * shard_size
lora_b = lora_b[:, start_idx:end_idx]
return lora_b
def slice_bias(self, bias: torch.Tensor) -> torch.Tensor:
# TODO: Fix the slicing logic of bias.
if bias is None:
return bias
tensor_model_parallel_rank = get_tensor_model_parallel_rank()
shard_size = self.output_size
start_idx = tensor_model_parallel_rank * shard_size
end_idx = (tensor_model_parallel_rank + 1) * shard_size
bias = bias[start_idx:end_idx]
return bias
def forward(
self, input_: torch.Tensor
) -> Union[torch.Tensor, tuple[torch.Tensor, Optional[torch.Tensor]]]:
"""Forward of ColumnParallelLinear
Args:
input_: Tensor whose last dimension is `input_size`.
Returns:
- output
- bias
"""
bias = (self.base_layer.bias
if not self.base_layer.skip_bias_add else None)
# Matrix multiply.
output_parallel = self.apply(input_, bias)
if self.base_layer.gather_output:
# All-gather across the partitions.
output = tensor_model_parallel_all_gather(output_parallel)
else:
output = output_parallel
if not self.base_layer.return_bias:
return output
output_bias = (self.base_layer.bias
if self.base_layer.skip_bias_add else None)
return output, output_bias
@classmethod
@_not_fully_sharded_can_replace
def can_replace_layer(
cls,
source_layer: nn.Module,
lora_config: LoRAConfig,
packed_modules_list: list,
model_config: Optional[PretrainedConfig],
) -> bool:
return type(source_layer) is ColumnParallelLinear or (
type(source_layer) is MergedColumnParallelLinear
and len(packed_modules_list) == 1)
class MergedColumnParallelLinearWithLoRA(ColumnParallelLinearWithLoRA):
"""ColumnParallelLinear layer that is composed of 2 sublayers (slices)
packed together (e.g. gate_proj + up_proj -> gate_up_proj).
This means we have 2 LoRAs, each applied to one half of the layer.
Both slices must have the same size.
"""
def __init__(
self, base_layer: Union[MergedColumnParallelLinear,
QKVParallelLinear]) -> None:
super().__init__(base_layer)
# There are two LoRA layers
self.tp_size = get_tensor_model_parallel_world_size()
self.tp_rank = get_tensor_model_parallel_rank()
# the output_sizes in MergedColumnParallelLinear is not sharded by tp
# we need to divide it by the tp_size to get correct slices size
output_sizes = self.base_layer.output_sizes
self.output_slices = tuple(
divide(output_size, self.tp_size) for output_size in output_sizes)
self.n_slices = len(self.output_slices)
self.output_ids = (self.tp_rank, ) * self.n_slices
def create_lora_weights(
self,
max_loras: int,
lora_config: LoRAConfig,
model_config: Optional[PretrainedConfig] = None,
) -> None:
"""
The main reason for overriding this function is to enhance code
maintainability.
"""
self.lora_config = lora_config
lora_a_output_size_per_partition = (
lora_config.max_lora_rank if not lora_config.fully_sharded_loras
else divide(lora_config.max_lora_rank, self.tp_size))
self.lora_a_stacked = tuple(
torch.zeros(
max_loras,
1,
lora_a_output_size_per_partition,
self.input_size,
dtype=lora_config.lora_dtype,
device=self.device,
) for _ in range(self.n_slices))
self.lora_b_stacked = tuple(
torch.zeros(
max_loras,
1,
output_size,
lora_config.max_lora_rank,
dtype=lora_config.lora_dtype,
device=self.device,
) for output_size in self.output_slices)
if lora_config.bias_enabled:
self.lora_bias_stacked = tuple(
torch.zeros(
max_loras,
1,
output_size,
dtype=lora_config.lora_dtype,
device=self.device,
) for output_size in self.output_slices)
def slice_lora_a(
self, lora_a: list[Union[torch.Tensor, None]]
) -> list[Union[torch.Tensor, None]]:
return lora_a
def slice_lora_b(
self, lora_b: list[Union[torch.Tensor, None]]
) -> list[Union[torch.Tensor, None]]:
sliced_lora_b = [None] * self.n_slices
for i, (shard_id, shard_size) in enumerate(
zip(self.output_ids, self.output_slices)):
if (lora_b_i := lora_b[i]) is not None:
sliced_lora_b[i] = lora_b_i[:,
shard_size * shard_id:shard_size *
(shard_id + 1)]
return sliced_lora_b
def slice_bias(
self, bias: list[Union[torch.Tensor,
None]]) -> list[Union[torch.Tensor, None]]:
for i, (shard_id, shard_size) in enumerate(
zip(self.output_ids, self.output_slices)):
if (bias_i := bias[i]) is not None:
bias[i] = bias_i[shard_size * shard_id:shard_size *
(shard_id + 1)]
return bias
def set_lora(
self,
index: int,
lora_a: torch.Tensor,
lora_b: torch.Tensor,
embeddings_tensor: Optional[torch.Tensor],
lora_bias: Optional[torch.Tensor] = None,
):
self.reset_lora(index)
if self.tp_size > 1:
lora_a = self.slice_lora_a(lora_a)
lora_b = self.slice_lora_b(lora_b)
if lora_bias is not None:
lora_bias = self.slice_bias(lora_bias)
for i in range(self.n_slices):
if (lora_a_i := lora_a[i]) is not None:
self.lora_a_stacked[i][
index, 0, :lora_a_i.shape[1], :lora_a_i.shape[0]].copy_(
lora_a_i.T, non_blocking=True)
if (lora_b_i := lora_b[i]) is not None:
self.lora_b_stacked[i][
index, 0, :lora_b_i.shape[1], :lora_b_i.shape[0]].copy_(
lora_b_i.T, non_blocking=True)
if lora_bias is not None:
self.lora_bias_stacked = cast(tuple[torch.Tensor, ...],
self.lora_bias_stacked)
for i in range(self.n_slices):
if (lora_bias_i := lora_bias[i]) is not None:
self.lora_bias_stacked[i][index,
0, :lora_bias_i.shape[0]].copy_(
lora_bias_i.T,
non_blocking=True)
@classmethod
@_not_fully_sharded_can_replace
def can_replace_layer(
cls,
source_layer: nn.Module,
lora_config: LoRAConfig,
packed_modules_list: list,
model_config: Optional[PretrainedConfig],
) -> bool:
return (type(source_layer) is MergedColumnParallelLinear
and len(packed_modules_list) == 2)
class QKVParallelLinearWithLoRA(ColumnParallelLinearWithLoRA):
"""
ColumnParallelLinear layer that is specifically designed for
qkv_proj. Certain models, such as chatglm3 and baichuan-7b,
only contains a single LoRA within their qkv_proj layer.
During inference with Tensor Parallel, the weights of lora_b
must be accurately partitioned according to the respective ranks.
Q slice may have different shape than K and V slices (which both have
the same shape).
"""
def __init__(self, base_layer: QKVParallelLinear) -> None:
super().__init__(base_layer)
self.q_proj_total_size = (self.base_layer.total_num_heads *
self.base_layer.head_size)
self.q_proj_shard_size = (self.base_layer.num_heads *
self.base_layer.head_size)
self.kv_proj_shard_size = (self.base_layer.num_kv_heads *
self.base_layer.head_size)
self.kv_proj_total_size = (self.base_layer.total_num_kv_heads *
self.base_layer.head_size)
# There is only one LoRA layer
self.n_slices = 1
def slice_lora_b(self, lora_b: torch.Tensor) -> torch.Tensor:
tp_rank = get_tensor_model_parallel_rank()
self.q_shard_id = tp_rank
self.kv_shard_id = tp_rank // self.base_layer.num_kv_head_replicas
lora_b_q = lora_b[:, self.q_proj_shard_size *
self.q_shard_id:self.q_proj_shard_size *
(self.q_shard_id + 1)]
k_offset = self.q_proj_total_size
lora_b_k = lora_b[:, k_offset +
self.kv_proj_shard_size * self.kv_shard_id:k_offset +
self.kv_proj_shard_size * (self.kv_shard_id + 1)]
v_offset = k_offset + self.kv_proj_total_size
lora_b_v = lora_b[:, v_offset +
self.kv_proj_shard_size * self.kv_shard_id:v_offset +
self.kv_proj_shard_size * (self.kv_shard_id + 1)]
lora_b = torch.cat([lora_b_q, lora_b_k, lora_b_v], dim=1)
return lora_b
def slice_bias(self, bias: torch.Tensor) -> torch.Tensor:
bias_q = bias[self.q_proj_shard_size *
self.q_shard_id:self.q_proj_shard_size *
(self.q_shard_id + 1)]
k_offset = self.q_proj_total_size
bias_k = bias[k_offset +
self.kv_proj_shard_size * self.kv_shard_id:k_offset +
self.kv_proj_shard_size * (self.kv_shard_id + 1)]
v_offset = k_offset + self.kv_proj_total_size
bias_v = bias[v_offset +
self.kv_proj_shard_size * self.kv_shard_id:v_offset +
self.kv_proj_shard_size * (self.kv_shard_id + 1)]
bias = torch.cat([bias_q, bias_k, bias_v], dim=1)
return bias
@classmethod
@_not_fully_sharded_can_replace
def can_replace_layer(cls, source_layer: nn.Module,
lora_config: LoRAConfig, packed_modules_list: list,
model_config: Optional[PretrainedConfig]) -> bool:
return type(source_layer) is QKVParallelLinear and len(
packed_modules_list) == 1
class MergedQKVParallelLinearWithLoRA(MergedColumnParallelLinearWithLoRA):
"""MergedColumnParallelLinear layer that is composed of 3 sublayers (slices)
packed together in qkv proj fashion
(q_proj + k_proj + v_proj -> qkv_proj).
This means we have 3 LoRAs, each applied to one slice of the layer.
Q slice may have different shape than K and V slices (which both have
the same shape).
"""
def __init__(self, base_layer: QKVParallelLinear) -> None:
super().__init__(base_layer)
# There are three LoRA layer.
self.n_slices = len(self.base_layer.output_sizes)
self.tp_size = get_tensor_model_parallel_world_size()
self.tp_rank = get_tensor_model_parallel_rank()
self.q_proj_shard_size = (self.base_layer.num_heads *
self.base_layer.head_size)
self.kv_proj_shard_size = (self.base_layer.num_kv_heads *
self.base_layer.head_size)
self.q_shard_id = self.tp_rank
self.kv_shard_id = self.tp_rank // self.base_layer.num_kv_head_replicas
self.output_slices = (
self.q_proj_shard_size,
self.kv_proj_shard_size,
self.kv_proj_shard_size,
)
self.output_ids = (
self.q_shard_id,
self.kv_shard_id,
self.kv_shard_id,
)
def create_lora_weights(
self,
max_loras: int,
lora_config: LoRAConfig,
model_config: Optional[PretrainedConfig] = None,
) -> None:
"""
The main reason for overloading this function is to handle inconsistent
weight dimensions in qkv lora.
"""
super().create_lora_weights(max_loras, lora_config, model_config)
@classmethod
@_not_fully_sharded_can_replace
def can_replace_layer(
cls,
source_layer: nn.Module,
lora_config: LoRAConfig,
packed_modules_list: list,
model_config: Optional[PretrainedConfig],
) -> bool:
return (type(source_layer) is QKVParallelLinear
and len(packed_modules_list) == 3)
# These following layers are based on the tensor parallelism strategy given in
# Y. Sheng et al., S-LoRA: Serving Thousands of Concurrent LoRA Adapters. 2023,
# https://arxiv.org/abs/2311.03285.
class ColumnParallelLinearWithShardedLoRA(ColumnParallelLinearWithLoRA):
"""
Differs from ColumnParallelLinearWithLoRA by slicing LoRA A also.
Based on S-LoRA, slicing happens along the rank dim.
"""
# For all LoRA layers where the `base_layer` is `ColumnParallelLinear`,
# their `lora_a` and `lora_b` have different sharding patterns. After
# completing the `lora_a` GEMM , a gather operation is performed.
# Therefore, the sharding of `lora_a` only needs to correspond with the
# gather operation.
def slice_lora_a(self, lora_a: torch.Tensor) -> torch.Tensor:
tp_rank = get_tensor_model_parallel_rank()
shard_size = self.lora_a_stacked[0].shape[2]
start_idx = tp_rank * shard_size
lora_a = lora_a[:, start_idx:start_idx + shard_size]
return lora_a
def apply(self,
x: torch.Tensor,
bias: Optional[torch.Tensor] = None) -> torch.Tensor:
return _mcp_apply(x, bias, self)
@classmethod
@_fully_sharded_can_replace
def can_replace_layer(
cls,
source_layer: nn.Module,
lora_config: LoRAConfig,
packed_modules_list: list,
model_config: Optional[PretrainedConfig],
) -> bool:
# specifying kwargs so they can be easily accessed in decorator
return super().can_replace_layer(
source_layer=source_layer,
lora_config=lora_config,
packed_modules_list=packed_modules_list,
model_config=model_config,
decorate=False,
)
class MergedColumnParallelLinearWithShardedLoRA(
MergedColumnParallelLinearWithLoRA):
"""
Differs from MergedColumnParallelLinearWithLoRA by slicing the
LoRA A's also.
Based on S-LoRA, slicing happens along the rank dim.
"""
def slice_lora_a(
self, lora_a: list[Union[torch.Tensor, None]]
) -> list[Union[torch.Tensor, None]]:
#NOTE: lora_a contains 2 subloras, and each sublora could be None.
output_shard_size = self.lora_a_stacked[0].shape[2]
output_start_idx = self.tp_rank * output_shard_size
lora_a = [
lora_a[0][:, output_start_idx:output_start_idx +
output_shard_size] if lora_a[0] is not None else None,
lora_a[1][:, output_start_idx:output_start_idx +
output_shard_size] if lora_a[1] is not None else None,
]
return lora_a
def apply(self,
x: torch.Tensor,
bias: Optional[torch.Tensor] = None) -> torch.Tensor:
return _mcp_apply(x, bias, self)
@classmethod
@_fully_sharded_can_replace
def can_replace_layer(
cls,
source_layer: nn.Module,
lora_config: LoRAConfig,
packed_modules_list: list,
model_config: Optional[PretrainedConfig],
) -> bool:
# specifying kwargs so they can be easily accessed in decorator
return super().can_replace_layer(
source_layer=source_layer,
lora_config=lora_config,
packed_modules_list=packed_modules_list,
model_config=model_config,
decorate=False,
)
class QKVParallelLinearWithShardedLoRA(QKVParallelLinearWithLoRA):
"""
Differs from QKVParallelLinearWithLoRA by slicing the
LoRA A's also.
Based on S-LoRA, slicing happens along the rank dim.
"""
def slice_lora_a(self, lora_a: torch.Tensor) -> torch.Tensor:
tp_rank = get_tensor_model_parallel_rank()
shard_size = self.lora_a_stacked[0].shape[2]
start_idx = tp_rank * shard_size
lora_a = lora_a[:, start_idx:start_idx + shard_size]
return lora_a
def apply(self,
x: torch.Tensor,
bias: Optional[torch.Tensor] = None) -> torch.Tensor:
return _mcp_apply(x, bias, self)
@classmethod
@_fully_sharded_can_replace
def can_replace_layer(cls, source_layer: nn.Module,
lora_config: LoRAConfig, packed_modules_list: list,
model_config: Optional[PretrainedConfig]) -> bool:
# specifying kwargs so they can be easily accessed in decorator
return super().can_replace_layer(
source_layer=source_layer,
lora_config=lora_config,
packed_modules_list=packed_modules_list,
model_config=model_config,
decorate=False,
)
class MergedQKVParallelLinearWithShardedLoRA(MergedQKVParallelLinearWithLoRA):
"""
Differs from MergedQKVParallelLinearWithLoRA by slicing the
LoRA A's also.
Based on S-LoRA, slicing happens along the rank dim.
"""
def slice_lora_a(
self, lora_a: list[Union[torch.Tensor, None]]
) -> list[Union[torch.Tensor, None]]:
# NOTE: lora_a contains 3 subloras, and each sublora could be None.
shard_size = [self.lora_a_stacked[i].shape[2] for i in range(3)]
start_idx = [self.tp_rank * shard_size[i] for i in range(3)]
lora_a = [
lora_a[0][:, start_idx[0]:start_idx[0] +
shard_size[0]] if lora_a[0] is not None else None,
lora_a[1][:, start_idx[1]:start_idx[1] +
shard_size[1]] if lora_a[1] is not None else None,
lora_a[2][:, start_idx[2]:start_idx[2] +
shard_size[2]] if lora_a[2] is not None else None,
]
return lora_a
def apply(self,
x: torch.Tensor,
bias: Optional[torch.Tensor] = None) -> torch.Tensor:
return _mcp_apply(x, bias, self)
@classmethod
@_fully_sharded_can_replace
def can_replace_layer(
cls,
source_layer: nn.Module,
lora_config: LoRAConfig,
packed_modules_list: list,
model_config: Optional[PretrainedConfig],
) -> bool:
# specifying kwargs so they can be easily accessed in decorator
return super().can_replace_layer(
source_layer=source_layer,
lora_config=lora_config,
packed_modules_list=packed_modules_list,
model_config=model_config,
decorate=False,
)