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vllm/vllm/model_executor/layers/fused_moe/layer.py
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from abc import abstractmethod
from typing import List, Optional, Tuple
import torch
from vllm.distributed import (get_tensor_model_parallel_rank,
get_tensor_model_parallel_world_size,
tensor_model_parallel_all_reduce)
from vllm.logger import init_logger
from vllm.model_executor.custom_op import CustomOp
from vllm.model_executor.layers.quantization.base_config import (
QuantizationConfig, QuantizeMethodBase)
from vllm.model_executor.utils import set_weight_attrs
logger = init_logger(__name__)
class FusedMoEMethodBase(QuantizeMethodBase):
@abstractmethod
def create_weights(self, layer: torch.nn.Module, num_experts: int,
hidden_size: int, intermediate_size: int,
params_dtype: torch.dtype, **extra_weight_attrs):
raise NotImplementedError
@abstractmethod
def apply(self,
layer: torch.nn.Module,
x: torch.Tensor,
router_logits: torch.Tensor,
top_k: int,
renormalize: bool = True,
use_grouped_topk: bool = False,
num_expert_group: Optional[int] = None,
topk_group: Optional[int] = None) -> torch.Tensor:
raise NotImplementedError
class UnquantizedFusedMoEMethod(FusedMoEMethodBase, CustomOp):
"""MoE method without quantization."""
def create_weights(self, layer: torch.nn.Module, num_experts: int,
hidden_size: int, intermediate_size: int,
params_dtype: torch.dtype, **extra_weight_attrs):
# Fused gate_up_proj (column parallel)
w13_weight = torch.nn.Parameter(torch.empty(num_experts,
2 * intermediate_size,
hidden_size,
dtype=params_dtype),
requires_grad=False)
layer.register_parameter("w13_weight", w13_weight)
set_weight_attrs(w13_weight, extra_weight_attrs)
# down_proj (row parallel)
w2_weight = torch.nn.Parameter(torch.empty(num_experts,
hidden_size,
intermediate_size,
dtype=params_dtype),
requires_grad=False)
layer.register_parameter("w2_weight", w2_weight)
set_weight_attrs(w2_weight, extra_weight_attrs)
def apply(
self,
layer: torch.nn.Module,
x: torch.Tensor,
router_logits: torch.Tensor,
top_k: int,
renormalize: bool = True,
use_grouped_topk: bool = False,
num_expert_group: Optional[int] = None,
topk_group: Optional[int] = None,
) -> torch.Tensor:
return self.forward(x, layer.w13_weight, layer.w2_weight,
router_logits, top_k, renormalize,
use_grouped_topk, num_expert_group, topk_group)
def forward_cuda(
self,
x: torch.Tensor,
w1: torch.Tensor,
w2: torch.Tensor,
router_logits: torch.Tensor,
top_k: int,
renormalize: bool,
use_grouped_topk: bool,
num_expert_group: Optional[int],
topk_group: Optional[int],
) -> torch.Tensor:
from vllm.model_executor.layers.fused_moe.fused_moe import fused_moe
return fused_moe(x,
w1,
w2,
router_logits,
top_k,
renormalize=renormalize,
inplace=True,
use_grouped_topk=use_grouped_topk,
num_expert_group=num_expert_group,
topk_group=topk_group)
def forward_cpu(self, *args, **kwargs):
raise NotImplementedError(
"The CPU backend currently does not support MoE.")
def forward_tpu(
self,
x: torch.Tensor,
w1: torch.Tensor,
w2: torch.Tensor,
router_logits: torch.Tensor,
top_k: int,
renormalize: bool,
use_grouped_topk: bool,
num_expert_group: Optional[int],
topk_group: Optional[int],
) -> torch.Tensor:
from vllm.model_executor.layers.fused_moe.moe_pallas import fused_moe
assert not use_grouped_topk
assert num_expert_group is None
assert topk_group is None
return fused_moe(x, w1, w2, router_logits, top_k, renormalize)
class FusedMoE(torch.nn.Module):
"""FusedMoE layer for MoE models.
This layer contains both MergedColumnParallel weights (gate_up_proj /
w13) and RowParallelLinear weights (down_proj/ w2).
Note: Mixtral uses w1, w2, and w3 for gate, up, and down_proj. We
copy that naming convention here and handle any remapping in the
load_weights function in each model implementation.
Args:
num_experts: Number of experts in the model
top_k: Number of experts selected for each token
hidden_size: Input hidden state size of the transformer
intermediate_size: Intermediate size of the experts
params_dtype: Data type for the parameters.
reduce_results: Whether to all all_reduce on the output of the layer
renomalize: Whether to renormalize the logits in the fused_moe kernel
quant_config: Quantization configure.
"""
def __init__(
self,
num_experts: int,
top_k: int,
hidden_size: int,
intermediate_size: int,
params_dtype: Optional[torch.dtype] = None,
reduce_results: bool = False,
renormalize: bool = True,
use_grouped_topk: bool = False,
num_expert_group: Optional[int] = None,
topk_group: Optional[int] = None,
quant_config: Optional[QuantizationConfig] = None,
tp_size: Optional[int] = None,
prefix: str = "",
):
super().__init__()
if params_dtype is None:
params_dtype = torch.get_default_dtype()
self.tp_size = (tp_size if tp_size is not None else
get_tensor_model_parallel_world_size())
self.top_k = top_k
self.num_experts = num_experts
self.intermediate_size_per_partition = intermediate_size // self.tp_size
self.reduce_results = reduce_results
self.renormalize = renormalize
self.use_grouped_topk = use_grouped_topk
if self.use_grouped_topk:
assert num_expert_group is not None and topk_group is not None
self.num_expert_group = num_expert_group
self.topk_group = topk_group
if quant_config is None:
self.quant_method: Optional[QuantizeMethodBase] = (
UnquantizedFusedMoEMethod())
else:
self.quant_method = quant_config.get_quant_method(self)
assert self.quant_method is not None
self.quant_method.create_weights(
layer=self,
num_experts=num_experts,
hidden_size=hidden_size,
intermediate_size=self.intermediate_size_per_partition,
params_dtype=params_dtype,
weight_loader=self.weight_loader)
def weight_loader(self, param: torch.nn.Parameter,
loaded_weight: torch.Tensor, weight_name: str,
shard_id: int, expert_id: int):
param_data = param.data
# Input scales can be loaded directly and should be equal.
if "input_scale" in weight_name:
if param_data[expert_id] != 1 and (param_data[expert_id] -
loaded_weight).abs() > 1e-5:
raise ValueError(
"input_scales of w1 and w3 of a layer "
f"must be equal. But got {param_data[expert_id]} "
f"vs. {loaded_weight}")
param_data[expert_id] = loaded_weight
# Weight scales
elif "weight_scale" in weight_name:
# If we are in merged column case (gate_up_proj)
# shard_id 0 == gate_proj / w1
# shard_id 2 == up_proj / w3
if shard_id == 0 or shard_id == 2:
# We have to keep the weight scales of w1 and w3 because
# we need to re-quantize w1/w3 weights after weight loading.
idx = 0 if shard_id == 0 else 1
param_data[expert_id][idx] = loaded_weight
# If we are in the row parallel case (down_proj)
# shard_id 1 == down_proj / w2
else:
param_data[expert_id] = loaded_weight
# Weights
else:
tp_rank = get_tensor_model_parallel_rank()
shard_size = self.intermediate_size_per_partition
shard = slice(tp_rank * shard_size, (tp_rank + 1) * shard_size)
# w1, gate_proj case: Load into first shard of w13.
if shard_id == 0:
param_data[expert_id,
0:shard_size, :] = loaded_weight[shard, :]
# w3, up_proj case: Load into second shard of w13.
elif shard_id == 2:
param_data[expert_id, shard_size:2 *
shard_size, :] = loaded_weight[shard, :]
# w2, down_proj case: Load into only shard of w2.
elif shard_id == 1:
param_data[expert_id, :, :] = loaded_weight[:, shard]
else:
raise ValueError(
f"Shard id must be in [0,1,2] but got {shard_id}")
def forward(self, hidden_states: torch.Tensor,
router_logits: torch.Tensor):
assert self.quant_method is not None
# Matrix multiply.
final_hidden_states = self.quant_method.apply(
self,
x=hidden_states,
router_logits=router_logits,
top_k=self.top_k,
renormalize=self.renormalize,
use_grouped_topk=self.use_grouped_topk,
num_expert_group=self.num_expert_group,
topk_group=self.topk_group)
if self.reduce_results and self.tp_size > 1:
final_hidden_states = tensor_model_parallel_all_reduce(
final_hidden_states)
return final_hidden_states
@classmethod
def make_expert_params_mapping(
cls, ckpt_gate_proj_name: str, ckpt_down_proj_name: str,
ckpt_up_proj_name: str,
num_experts: int) -> List[Tuple[str, str, int, int]]:
gate_up = [ckpt_gate_proj_name, ckpt_up_proj_name]
gate_down_up = [
ckpt_gate_proj_name, ckpt_down_proj_name, ckpt_up_proj_name
]
return [
# These are the weight scales for the experts
# (param_name, weight_name, expert_id, shard_id)
("experts.w13_scale"
if weight_name in gate_up else "experts.w2_scale",
f"experts.{expert_id}.{weight_name}.weight_scale", expert_id,
shard_id) for expert_id in range(num_experts)
for shard_id, weight_name in enumerate(gate_down_up)
] + [
# These are the weights for the experts
# (param_name, weight_name, expert_id, shard_id)
("experts.w13_weight"
if weight_name in gate_up else "experts.w2_weight",
f"experts.{expert_id}.{weight_name}.weight", expert_id, shard_id)
for expert_id in range(num_experts)
for shard_id, weight_name in enumerate(gate_down_up)
] + [
# These are the weight scales for the experts
# (param_name, weight_name, expert_id, shard_id)
("experts.a13_scale"
if weight_name in gate_up else "experts.a2_scale",
f"experts.{expert_id}.{weight_name}.input_scale", expert_id,
shard_id) for expert_id in range(num_experts)
for shard_id, weight_name in enumerate(gate_down_up)
]