vllm/vllm/model_executor/models/mixtral.py
Philipp Moritz 12628d3c78
[Kernel] Optimize FP8 support for MoE kernel / Mixtral via static scales (#4343)
Co-authored-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>
2024-04-27 04:49:59 +00:00

519 lines
20 KiB
Python

# coding=utf-8
# Adapted from
# https://github.com/huggingface/transformers/blob/v4.28.0/src/transformers/models/llama/modeling_llama.py
# Copyright 2023 The vLLM team.
# Copyright 2022 EleutherAI and the HuggingFace Inc. team. All rights reserved.
#
# This code is based on EleutherAI's GPT-NeoX library and the GPT-NeoX
# and OPT implementations in this library. It has been modified from its
# original forms to accommodate minor architectural differences compared
# to GPT-NeoX and OPT used by the Meta AI team that trained the model.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Inference-only Mixtral model."""
from typing import Iterable, List, Optional, Tuple
import torch
from torch import nn
from transformers import MixtralConfig
from vllm import _custom_ops as ops
from vllm.attention import Attention, AttentionMetadata
from vllm.config import LoRAConfig
from vllm.distributed import (get_tensor_model_parallel_rank,
get_tensor_model_parallel_world_size,
tensor_model_parallel_all_reduce)
from vllm.model_executor.layers.fused_moe import fused_moe
from vllm.model_executor.layers.layernorm import RMSNorm
from vllm.model_executor.layers.linear import (QKVParallelLinear,
ReplicatedLinear,
RowParallelLinear)
from vllm.model_executor.layers.logits_processor import LogitsProcessor
from vllm.model_executor.layers.quantization.base_config import (
QuantizationConfig)
from vllm.model_executor.layers.quantization.fp8 import Fp8Config
from vllm.model_executor.layers.rotary_embedding import get_rope
from vllm.model_executor.layers.sampler import Sampler
from vllm.model_executor.layers.vocab_parallel_embedding import (
DEFAULT_VOCAB_PADDING_SIZE, ParallelLMHead, VocabParallelEmbedding)
from vllm.model_executor.model_loader.weight_utils import default_weight_loader
from vllm.model_executor.sampling_metadata import SamplingMetadata
from vllm.model_executor.utils import set_weight_attrs
from vllm.sequence import SamplerOutput
from vllm.utils import print_warning_once
class MixtralMoE(nn.Module):
"""A tensor-parallel MoE implementation for Mixtral that shards each expert
across all ranks.
Each expert's weights are sharded across all ranks and a fused MoE
kernel is used for the forward pass, and finally we reduce the outputs
across ranks.
"""
def __init__(
self,
num_experts: int,
top_k: int,
hidden_size: int,
intermediate_size: int,
params_dtype: Optional[torch.dtype] = None,
tp_size: Optional[int] = None,
quant_config: Optional[QuantizationConfig] = None,
):
super().__init__()
self.tp_size = tp_size or get_tensor_model_parallel_world_size()
self.num_total_experts = num_experts
self.top_k = top_k
self.hidden_size = hidden_size
self.intermediate_size = intermediate_size // self.tp_size
# FIXME(pcmoritz): Make this more general to support different
# quantization schemes
self.use_fp8 = isinstance(quant_config, Fp8Config)
if params_dtype is None:
params_dtype = torch.get_default_dtype()
self.params_dtype = params_dtype
self.gate = ReplicatedLinear(self.hidden_size,
self.num_total_experts,
bias=False,
params_dtype=self.params_dtype,
quant_config=None)
self.ws = nn.Parameter(
torch.empty(self.num_total_experts,
2 * self.intermediate_size,
self.hidden_size,
device="cuda",
dtype=self.params_dtype))
self.w2s = nn.Parameter(
torch.empty(self.num_total_experts,
self.hidden_size,
self.intermediate_size,
device="cuda",
dtype=self.params_dtype))
set_weight_attrs(self.ws, {
"weight_loader": self.weight_loader,
})
set_weight_attrs(self.w2s, {
"weight_loader": self.weight_loader,
})
# Scaling factors for FP8 weights
self.ws_scale = nn.Parameter(
torch.ones(
self.num_total_experts, device="cuda", dtype=torch.float32),
requires_grad=False) if self.use_fp8 else None
self.w2s_scale = nn.Parameter(
torch.ones(
self.num_total_experts, device="cuda", dtype=torch.float32),
requires_grad=False) if self.use_fp8 else None
# Scaling factors for FP8 activations
need_act_scales = (self.use_fp8
and quant_config.activation_scheme == "static")
self.as_scale = nn.Parameter(
torch.zeros(1, device="cuda", dtype=torch.float32),
requires_grad=False) if need_act_scales else None
self.a2s_scale = nn.Parameter(
torch.zeros(1, device="cuda", dtype=torch.float32),
requires_grad=False) if need_act_scales else None
if need_act_scales:
set_weight_attrs(self.as_scale, {
"weight_loader": self.weight_loader,
})
set_weight_attrs(self.a2s_scale, {
"weight_loader": self.weight_loader,
})
def weight_loader(self, param: nn.Parameter, loaded_weight: torch.Tensor,
weight_name: str, expert_id: int):
tp_rank = get_tensor_model_parallel_rank()
param_data = param.data
shard_size = self.intermediate_size
shard = slice(tp_rank * shard_size, (tp_rank + 1) * shard_size)
if weight_name.endswith("w1.weight"):
param_data[expert_id, 0:shard_size, :] = loaded_weight[shard, :]
if weight_name.endswith("w3.weight"):
param_data[expert_id,
shard_size:2 * shard_size, :] = loaded_weight[shard, :]
if weight_name.endswith("w2.weight"):
param_data[expert_id, :, :] = loaded_weight[:, shard]
if "act_scale" in weight_name:
param_data[:] = param_data[:].max(loaded_weight)
def process_weights_after_loading(self):
if self.use_fp8:
ws = torch.empty_like(self.ws.data, dtype=torch.float8_e4m3fn)
w2s = torch.empty_like(self.w2s.data, dtype=torch.float8_e4m3fn)
for expert in range(self.num_total_experts):
ws[expert, :, :], self.ws_scale[expert] = ops.scaled_fp8_quant(
self.ws.data[expert, :, :])
w2s[expert, :, :], self.w2s_scale[
expert] = ops.scaled_fp8_quant(self.w2s.data[expert, :, :])
self.ws = nn.Parameter(ws, requires_grad=False)
self.w2s = nn.Parameter(w2s, requires_grad=False)
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
num_tokens, hidden_size = hidden_states.shape
hidden_states = hidden_states.view(-1, self.hidden_size)
# router_logits: (num_tokens, n_experts)
router_logits, _ = self.gate(hidden_states)
final_hidden_states = fused_moe(hidden_states,
self.ws,
self.w2s,
router_logits,
self.top_k,
renormalize=True,
inplace=True,
use_fp8=self.use_fp8,
w1_scale=self.ws_scale,
w2_scale=self.w2s_scale,
a1_scale=self.as_scale,
a2_scale=self.a2s_scale)
if self.tp_size > 1:
final_hidden_states = tensor_model_parallel_all_reduce(
final_hidden_states)
return final_hidden_states.view(num_tokens, hidden_size)
class MixtralAttention(nn.Module):
def __init__(self,
hidden_size: int,
num_heads: int,
num_kv_heads: int,
max_position: int = 4096 * 32,
rope_theta: float = 10000,
quant_config: Optional[QuantizationConfig] = None,
sliding_window: Optional[int] = None) -> None:
super().__init__()
self.hidden_size = hidden_size
tp_size = get_tensor_model_parallel_world_size()
self.total_num_heads = num_heads
assert self.total_num_heads % tp_size == 0
self.num_heads = self.total_num_heads // tp_size
self.total_num_kv_heads = num_kv_heads
if self.total_num_kv_heads >= tp_size:
# Number of KV heads is greater than TP size, so we partition
# the KV heads across multiple tensor parallel GPUs.
assert self.total_num_kv_heads % tp_size == 0
else:
# Number of KV heads is less than TP size, so we replicate
# the KV heads across multiple tensor parallel GPUs.
assert tp_size % self.total_num_kv_heads == 0
self.num_kv_heads = max(1, self.total_num_kv_heads // tp_size)
self.head_dim = hidden_size // self.total_num_heads
self.q_size = self.num_heads * self.head_dim
self.kv_size = self.num_kv_heads * self.head_dim
self.scaling = self.head_dim**-0.5
self.rope_theta = rope_theta
self.sliding_window = sliding_window
if isinstance(quant_config, Fp8Config):
print_warning_once(
"For Mixtral FP8 quantization, we currently do not quantize "
"the attention layers until their FP8 performance is improved."
)
quant_config = None
self.qkv_proj = QKVParallelLinear(
hidden_size,
self.head_dim,
self.total_num_heads,
self.total_num_kv_heads,
bias=False,
quant_config=quant_config,
)
self.o_proj = RowParallelLinear(
self.total_num_heads * self.head_dim,
hidden_size,
bias=False,
quant_config=quant_config,
)
self.rotary_emb = get_rope(
self.head_dim,
rotary_dim=self.head_dim,
max_position=max_position,
base=int(self.rope_theta),
is_neox_style=True,
)
self.attn = Attention(
self.num_heads,
self.head_dim,
self.scaling,
num_kv_heads=self.num_kv_heads,
sliding_window=self.sliding_window,
)
def forward(
self,
positions: torch.Tensor,
hidden_states: torch.Tensor,
kv_cache: torch.Tensor,
attn_metadata: AttentionMetadata,
) -> torch.Tensor:
qkv, _ = self.qkv_proj(hidden_states)
q, k, v = qkv.split([self.q_size, self.kv_size, self.kv_size], dim=-1)
q, k = self.rotary_emb(positions, q, k)
attn_output = self.attn(q, k, v, kv_cache, attn_metadata)
output, _ = self.o_proj(attn_output)
return output
class MixtralDecoderLayer(nn.Module):
def __init__(
self,
config: MixtralConfig,
quant_config: Optional[QuantizationConfig] = None,
) -> None:
super().__init__()
self.hidden_size = config.hidden_size
# Requires transformers > 4.32.0
rope_theta = getattr(config, "rope_theta", 10000)
self.self_attn = MixtralAttention(
hidden_size=self.hidden_size,
num_heads=config.num_attention_heads,
max_position=config.max_position_embeddings,
num_kv_heads=config.num_key_value_heads,
rope_theta=rope_theta,
sliding_window=config.sliding_window,
quant_config=quant_config)
self.block_sparse_moe = MixtralMoE(
num_experts=config.num_local_experts,
top_k=config.num_experts_per_tok,
hidden_size=config.hidden_size,
intermediate_size=config.intermediate_size,
quant_config=quant_config)
self.input_layernorm = RMSNorm(config.hidden_size,
eps=config.rms_norm_eps)
self.post_attention_layernorm = RMSNorm(config.hidden_size,
eps=config.rms_norm_eps)
def forward(
self,
positions: torch.Tensor,
hidden_states: torch.Tensor,
kv_cache: torch.Tensor,
attn_metadata: AttentionMetadata,
residual: Optional[torch.Tensor],
) -> torch.Tensor:
# Self Attention
if residual is None:
residual = hidden_states
hidden_states = self.input_layernorm(hidden_states)
else:
hidden_states, residual = self.input_layernorm(
hidden_states, residual)
hidden_states = self.self_attn(
positions=positions,
hidden_states=hidden_states,
kv_cache=kv_cache,
attn_metadata=attn_metadata,
)
# Fully Connected
hidden_states, residual = self.post_attention_layernorm(
hidden_states, residual)
hidden_states = self.block_sparse_moe(hidden_states)
return hidden_states, residual
class MixtralModel(nn.Module):
def __init__(
self,
config: MixtralConfig,
quant_config: Optional[QuantizationConfig] = None,
lora_config: Optional[LoRAConfig] = None,
) -> None:
super().__init__()
self.padding_idx = config.pad_token_id
lora_vocab = (lora_config.lora_extra_vocab_size *
(lora_config.max_loras or 1)) if lora_config else 0
self.vocab_size = config.vocab_size + lora_vocab
self.org_vocab_size = config.vocab_size
self.embed_tokens = VocabParallelEmbedding(
self.vocab_size,
config.hidden_size,
org_num_embeddings=config.vocab_size,
)
self.layers = nn.ModuleList([
MixtralDecoderLayer(config, quant_config=quant_config)
for _ in range(config.num_hidden_layers)
])
self.norm = RMSNorm(config.hidden_size, eps=config.rms_norm_eps)
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
kv_caches: List[torch.Tensor],
attn_metadata: AttentionMetadata,
) -> torch.Tensor:
hidden_states = self.embed_tokens(input_ids)
residual = None
for i in range(len(self.layers)):
layer = self.layers[i]
hidden_states, residual = layer(positions, hidden_states,
kv_caches[i], attn_metadata,
residual)
hidden_states, _ = self.norm(hidden_states, residual)
return hidden_states
class MixtralForCausalLM(nn.Module):
fall_back_to_pt_during_load = False
packed_modules_mapping = {
"qkv_proj": [
"q_proj",
"k_proj",
"v_proj",
],
}
# LoRA specific attributes
supported_lora_modules = [
"qkv_proj",
"o_proj",
"embed_tokens",
"lm_head",
]
embedding_modules = {
"embed_tokens": "input_embeddings",
"lm_head": "output_embeddings",
}
embedding_padding_modules = ["lm_head"]
def __init__(
self,
config: MixtralConfig,
quant_config: Optional[QuantizationConfig] = None,
lora_config: Optional[LoRAConfig] = None,
) -> None:
super().__init__()
self.config = config
self.model = MixtralModel(config,
quant_config,
lora_config=lora_config)
self.unpadded_vocab_size = config.vocab_size
if lora_config:
self.unpadded_vocab_size += lora_config.lora_extra_vocab_size
self.lm_head = ParallelLMHead(
self.unpadded_vocab_size,
config.hidden_size,
org_num_embeddings=config.vocab_size,
padding_size=DEFAULT_VOCAB_PADDING_SIZE
# We need bigger padding if using lora for kernel
# compatibility
if not lora_config else lora_config.lora_vocab_padding_size,
)
self.logits_processor = LogitsProcessor(self.unpadded_vocab_size,
config.vocab_size)
self.sampler = Sampler()
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
kv_caches: List[torch.Tensor],
attn_metadata: AttentionMetadata,
) -> torch.Tensor:
hidden_states = self.model(input_ids, positions, kv_caches,
attn_metadata)
return hidden_states
def compute_logits(self, hidden_states: torch.Tensor,
sampling_metadata: SamplingMetadata) -> torch.Tensor:
logits = self.logits_processor(self.lm_head.weight, hidden_states,
sampling_metadata)
return logits
def sample(
self,
logits: Optional[torch.Tensor],
sampling_metadata: SamplingMetadata,
) -> Optional[SamplerOutput]:
next_tokens = self.sampler(logits, sampling_metadata)
return next_tokens
def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
stacked_params_mapping = [
# (param_name, shard_name, shard_id)
("qkv_proj", "q_proj", "q"),
("qkv_proj", "k_proj", "k"),
("qkv_proj", "v_proj", "v"),
]
expert_params_mapping = [
# These are the weights for the experts
# (param_name, weight_name, expert_id)
("ws" if weight_name in ["w1", "w3"] else "w2s",
f"experts.{expert_id}.{weight_name}.weight", expert_id)
for expert_id in range(self.config.num_local_experts)
for weight_name in ["w1", "w2", "w3"]
] + [
# These are the activation scales for the experts
# (param_name, weight_name, expert_id)
("as_scale" if weight_name in ["w1", "w3"] else "a2s_scale",
f"experts.{expert_id}.{weight_name}.act_scale", expert_id)
for expert_id in range(self.config.num_local_experts)
for weight_name in ["w1", "w2", "w3"]
]
params_dict = dict(self.named_parameters())
for name, loaded_weight in weights:
if "rotary_emb.inv_freq" in name:
continue
for (param_name, weight_name, shard_id) in stacked_params_mapping:
if weight_name not in name:
continue
name = name.replace(weight_name, param_name)
# Skip loading extra bias for GPTQ models.
if name.endswith(".bias") and name not in params_dict:
continue
param = params_dict[name]
weight_loader = param.weight_loader
weight_loader(param, loaded_weight, shard_id)
break
else:
for param_name, weight_name, expert_id in expert_params_mapping:
if weight_name not in name:
continue
name = name.replace(weight_name, param_name)
param = params_dict[name]
weight_loader = param.weight_loader
weight_loader(param,
loaded_weight,
weight_name,
expert_id=expert_id)
break
else:
# Skip loading extra bias for GPTQ models.
if name.endswith(".bias") and name not in params_dict:
continue
param = params_dict[name]
weight_loader = getattr(param, "weight_loader",
default_weight_loader)
weight_loader(param, loaded_weight)