TensorRT-LLMs/tensorrt_llm/_torch/modules/attention.py
Kaiyu Xie 2631f21089
Update (#2978)
Signed-off-by: Kaiyu Xie <26294424+kaiyux@users.noreply.github.com>
2025-03-23 16:39:35 +08:00

645 lines
25 KiB
Python

from typing import Optional
import torch
from torch import nn
from ..attention_backend import (AttentionInputType, AttentionMetadata,
TrtllmAttention)
from ..attention_backend.interface import (PositionalEmbeddingParams,
PredefinedAttentionMask)
from ..attention_backend.utils import create_attention
from ..distributed import AllReduceParams, ParallelConfig, TensorParallelMode
from ..model_config import ModelConfig
from .linear import Linear, WeightMode, WeightsLoadingConfig
from .rms_norm import RMSNorm
from .rotary_embedding import RotaryEmbedding
class Attention(nn.Module):
def __init__(
self,
*,
hidden_size: int,
num_attention_heads: int,
num_key_value_heads: int,
max_position_embeddings: int,
bias: bool,
pos_embd_params: Optional[PositionalEmbeddingParams] = None,
rotary_emb: Optional[RotaryEmbedding] = None,
layer_idx: Optional[int] = None,
dtype: torch.dtype = None,
dense_bias: Optional[bool] = None,
config: Optional[ModelConfig] = None,
):
super().__init__()
self.layer_idx = layer_idx
self.hidden_size = hidden_size
self.num_heads = num_attention_heads
self.head_dim = self.hidden_size // self.num_heads
self.num_key_value_heads = num_key_value_heads
self.num_key_value_groups = self.num_heads // self.num_key_value_heads
self.max_position_embeddings = max_position_embeddings
self.pos_embd_params = pos_embd_params
self.dense_bias = dense_bias
if dense_bias is None:
self.dense_bias = bias
if (self.head_dim * self.num_heads) != self.hidden_size:
raise ValueError(
f"hidden_size must be divisible by num_heads (got `hidden_size`: {self.hidden_size}"
f" and `num_heads`: {self.num_heads}).")
# tensor parallel
config = config or ModelConfig()
tp_size = config.mapping.tp_size
tp_rank = config.mapping.tp_rank
gpus_per_node = config.mapping.gpus_per_node
if config.mapping.enable_attention_dp:
tp_size = 1
tp_rank = 0
assert self.num_heads % tp_size == 0
self.num_heads = self.num_heads // tp_size
self.num_key_value_heads = (self.num_key_value_heads + tp_size -
1) // tp_size
self.q_size = self.num_heads * self.head_dim
self.kv_size = self.num_key_value_heads * self.head_dim
self.qkv_proj = Linear(
self.hidden_size,
tp_size * self.q_size + 2 * tp_size * self.kv_size,
bias=bias,
dtype=dtype,
parallel_config=ParallelConfig(
tensor_parallel_size=tp_size,
tensor_parallel_rank=tp_rank,
tensor_parallel_mode=TensorParallelMode.COLUMN,
gpus_per_node=gpus_per_node,
pipeline_parallel_size=config.mapping.pp_size,
parallel_rank=config.mapping.rank),
weights_loading_config=WeightsLoadingConfig(
weight_mode=WeightMode.FUSED_QKV_LINEAR),
quant_config=config.get_quant_config(),
skip_create_weights=config.skip_create_weights,
)
self.o_proj = Linear(
self.hidden_size,
self.hidden_size,
bias=self.dense_bias,
dtype=dtype,
parallel_config=ParallelConfig(
tensor_parallel_size=tp_size,
tensor_parallel_rank=tp_rank,
tensor_parallel_mode=TensorParallelMode.ROW,
gpus_per_node=gpus_per_node,
pipeline_parallel_size=config.mapping.pp_size,
parallel_rank=config.mapping.rank),
quant_config=config.get_quant_config(),
skip_create_weights=config.skip_create_weights,
)
self.quant_config = config.get_quant_config()
self.attn_backend = config.attn_backend
self.pos_embd_params = pos_embd_params
self.rotary_emb = rotary_emb
if not config.skip_create_weights:
self.create_weights()
def create_weights(self):
self.attn = create_attention(
self.attn_backend,
self.layer_idx,
self.num_heads,
self.head_dim,
self.num_key_value_heads,
pos_embd_params=self.pos_embd_params,
quant_config=self.quant_config,
)
def forward(
self,
position_ids: Optional[torch.LongTensor],
hidden_states: torch.Tensor,
attn_metadata: AttentionMetadata,
attention_mask: PredefinedAttentionMask = PredefinedAttentionMask.
CAUSAL,
mrope_config: Optional[dict] = None,
**kwargs,
) -> torch.Tensor:
qkv = self.qkv_proj(hidden_states)
is_fused_qkv = False
if isinstance(self.attn, TrtllmAttention):
is_fused_qkv = True
if is_fused_qkv:
if self.pos_embd_params is None and position_ids is not None:
q, k, v = qkv.split([self.q_size, self.kv_size, self.kv_size],
dim=-1)
q, k = self.rotary_emb(
position_ids,
[q.contiguous(), k.contiguous()], attn_metadata)
qkv = torch.concat(
[q.contiguous(),
k.contiguous(),
v.contiguous()], dim=-1)
out_scale = None
if self.o_proj.has_fp8_qdq or self.o_proj.has_nv_fp4 or self.o_proj.has_fp8_block_scales:
out_scale = self.o_proj.inv_input_scale
attn_output = self.attn.forward(qkv,
None,
None,
attn_metadata,
out_scale=out_scale,
attention_mask=attention_mask,
mrope_config=mrope_config)
else:
q, k, v = qkv.split([self.q_size, self.kv_size, self.kv_size],
dim=-1)
if self.pos_embd_params is None and position_ids is not None:
q, k = self.rotary_emb(
position_ids,
[q.contiguous(), k.contiguous()], attn_metadata)
attn_output = self.attn.forward(q.contiguous(),
k.contiguous(),
v.contiguous(),
attn_metadata,
attention_mask=attention_mask,
mrope_config=mrope_config)
attn_output = self.o_proj(attn_output)
return attn_output
class MLA(nn.Module):
def __init__(
self,
*,
hidden_size: int,
num_attention_heads: int,
num_key_value_heads: int,
qk_nope_head_dim: int,
qk_rope_head_dim: int,
v_head_dim: int,
q_lora_rank: int,
kv_lora_rank: int,
predicted_tokens_per_seq: int,
max_position_embeddings: int,
bias: bool,
aux_stream: Optional[torch.cuda.Stream] = None,
pos_embd_params: Optional[PositionalEmbeddingParams] = None,
rotary_emb: Optional[RotaryEmbedding] = None,
layer_idx: Optional[int] = None,
dtype: torch.dtype = None,
dense_bias: Optional[bool] = None,
config: Optional[ModelConfig] = None,
):
super().__init__()
self.layer_idx = layer_idx
self.hidden_size = hidden_size
self.num_heads = num_attention_heads
self.head_dim = self.hidden_size // self.num_heads
self.num_key_value_heads = num_key_value_heads
self.num_key_value_groups = self.num_heads // self.num_key_value_heads
self.qk_nope_head_dim = qk_nope_head_dim
self.qk_rope_head_dim = qk_rope_head_dim
self.v_head_dim = v_head_dim
self.q_lora_rank = q_lora_rank
self.kv_lora_rank = kv_lora_rank
self.predicted_tokens_per_seq = predicted_tokens_per_seq
self.max_position_embeddings = max_position_embeddings
self.pos_embd_params = pos_embd_params
self.dense_bias = dense_bias
if dense_bias is None:
self.dense_bias = bias
if self.q_lora_rank is None:
self.q_lora_rank = hidden_size
self.is_lite = True
else:
self.is_lite = False
if (self.head_dim * self.num_heads) != self.hidden_size:
raise ValueError(
f"hidden_size must be divisible by num_heads (got `hidden_size`: {self.hidden_size}"
f" and `num_heads`: {self.num_heads}).")
# tensor parallel
config = config or ModelConfig()
tp_size = config.mapping.tp_size
tp_rank = config.mapping.tp_rank
gpus_per_node = config.mapping.gpus_per_node
if config.mapping.enable_attention_dp:
tp_size = 1
tp_rank = 0
row_parallel_config = ParallelConfig(
tensor_parallel_rank=tp_rank,
tensor_parallel_size=tp_size,
tensor_parallel_mode=TensorParallelMode.ROW,
gpus_per_node=gpus_per_node,
pipeline_parallel_size=config.mapping.pp_size,
parallel_rank=config.mapping.rank,
)
col_parallel_config = ParallelConfig(
tensor_parallel_rank=tp_rank,
tensor_parallel_size=tp_size,
tensor_parallel_mode=TensorParallelMode.COLUMN,
gpus_per_node=gpus_per_node,
pipeline_parallel_size=config.mapping.pp_size,
parallel_rank=config.mapping.rank,
)
assert self.num_heads % tp_size == 0
self.num_heads = self.num_heads // tp_size
self.num_key_value_heads = (self.num_key_value_heads + tp_size -
1) // tp_size
rms_norm_eps = config.pretrained_config.rms_norm_eps
quant_config = config.get_quant_config()
quant_mode = quant_config.quant_mode
if not self.is_lite:
self.fused_a = Linear(
hidden_size,
self.q_lora_rank + self.kv_lora_rank + self.qk_rope_head_dim,
bias=bias,
dtype=dtype,
quant_config=quant_config,
skip_create_weights=config.skip_create_weights,
use_custom_cublas_mm=True)
self.q_a_layernorm = RMSNorm(hidden_size=self.q_lora_rank,
eps=rms_norm_eps,
dtype=dtype)
self.q_b_proj = Linear(
self.q_lora_rank,
tp_size * self.num_heads *
(self.qk_nope_head_dim + self.qk_rope_head_dim),
bias=bias,
dtype=dtype,
parallel_config=col_parallel_config,
quant_config=quant_config,
skip_create_weights=config.skip_create_weights)
else:
self.fused_a = Linear(
hidden_size,
self.kv_lora_rank + self.qk_rope_head_dim,
bias=bias,
dtype=dtype,
quant_config=quant_config,
skip_create_weights=config.skip_create_weights,
use_custom_cublas_mm=True)
self.q_proj = Linear(
self.q_lora_rank,
tp_size * self.num_heads *
(self.qk_nope_head_dim + self.qk_rope_head_dim),
bias=bias,
dtype=dtype,
parallel_config=col_parallel_config,
quant_config=quant_config,
skip_create_weights=config.skip_create_weights)
self.q_b_proj = self.q_proj
self.kv_a_layernorm = RMSNorm(hidden_size=kv_lora_rank,
dtype=dtype,
eps=rms_norm_eps)
if quant_mode.has_fp8_block_scales():
mla_weight_dtype = torch.float8_e4m3fn
else:
mla_weight_dtype = dtype
self.kv_b_proj = Linear(self.kv_lora_rank,
tp_size * self.num_heads *
(self.qk_nope_head_dim + self.v_head_dim),
bias=bias,
dtype=dtype,
parallel_config=col_parallel_config,
quant_config=quant_config,
skip_create_weights=config.skip_create_weights)
# This parameter will view into self.kv_b_proj.weight after loading weights.
# For dummy weight initialization, this parameter is initialized with empty tensor.
self.v_b_proj = nn.Parameter(
torch.empty(
(self.num_heads, self.v_head_dim, self.kv_lora_rank),
dtype=dtype,
),
requires_grad=False,
)
self.k_b_proj_trans = nn.Parameter(
torch.empty(
(self.num_heads, self.kv_lora_rank, self.qk_nope_head_dim),
dtype=mla_weight_dtype,
),
requires_grad=False,
)
if quant_mode.has_fp8_block_scales():
self.k_b_proj_trans_scale = nn.Parameter(
torch.empty(
(
self.num_heads,
self.kv_lora_rank // 128,
self.qk_nope_head_dim // 128,
),
dtype=torch.float32,
),
requires_grad=False,
)
# This parameter will view into self.kv_b_proj.weight_scale after loading weights.
# For dummy weight initialization, this parameter is initialized with empty tensor.
self.v_b_proj_scale = nn.Parameter(
torch.empty(
(
self.num_heads,
self.v_head_dim // 128,
self.kv_lora_rank // 128,
),
dtype=torch.float32,
),
requires_grad=False,
)
else:
self.k_b_proj_trans_scale = None
self.v_b_proj_scale = None
self.o_proj = Linear(
self.num_key_value_heads * self.v_head_dim * tp_size,
self.hidden_size,
bias=self.dense_bias,
dtype=dtype,
parallel_config=row_parallel_config,
quant_config=quant_config,
skip_create_weights=config.skip_create_weights,
)
self.mha = create_attention(
config.attn_backend,
self.layer_idx,
self.num_heads,
self.qk_nope_head_dim + self.qk_rope_head_dim,
self.num_key_value_heads,
pos_embd_params=pos_embd_params,
quant_config=quant_config,
is_mla_enable=True,
q_lora_rank=self.q_lora_rank,
kv_lora_rank=self.kv_lora_rank,
qk_nope_head_dim=self.qk_nope_head_dim,
qk_rope_head_dim=self.qk_rope_head_dim,
v_head_dim=self.v_head_dim,
predicted_tokens_per_seq=self.predicted_tokens_per_seq,
)
self.mqa = create_attention(
config.attn_backend,
self.layer_idx,
self.num_heads,
self.kv_lora_rank + self.qk_rope_head_dim,
1, # num_kv_heads
pos_embd_params=pos_embd_params,
quant_config=quant_config,
is_mla_enable=True,
q_lora_rank=self.q_lora_rank,
kv_lora_rank=self.kv_lora_rank,
qk_nope_head_dim=self.qk_nope_head_dim,
qk_rope_head_dim=self.qk_rope_head_dim,
v_head_dim=self.kv_lora_rank,
predicted_tokens_per_seq=self.predicted_tokens_per_seq,
)
self.rotary_emb = rotary_emb
self.aux_stream = aux_stream
self.ln_events = [torch.cuda.Event(), torch.cuda.Event()]
def forward(
self,
position_ids: Optional[torch.LongTensor],
hidden_states: torch.Tensor,
attn_metadata: AttentionMetadata,
all_reduce_params: Optional[AllReduceParams] = None,
) -> torch.Tensor:
if self.is_lite:
compressed_kv, k_pe = self.fused_a(hidden_states).split(
[self.kv_lora_rank, self.qk_rope_head_dim], -1)
compressed_kv = self.kv_a_layernorm(compressed_kv)
compressed_q = hidden_states
else:
compressed_q, compressed_kv, k_pe = self.fused_a(
hidden_states).split([
self.q_lora_rank, self.kv_lora_rank, self.qk_rope_head_dim
], -1)
do_multi_stream = torch.cuda.is_current_stream_capturing(
) and self.aux_stream is not None
if do_multi_stream:
self.ln_events[0].record()
compressed_kv = self.kv_a_layernorm(compressed_kv)
with torch.cuda.stream(self.aux_stream):
self.ln_events[0].wait()
compressed_q = self.q_a_layernorm(compressed_q)
self.ln_events[1].record()
self.ln_events[1].wait()
else:
compressed_q = self.q_a_layernorm(compressed_q)
compressed_kv = self.kv_a_layernorm(compressed_kv)
q = self.q_b_proj(compressed_q)
# split q, k, v into context and gen batches
num_contexts = attn_metadata.num_contexts
num_generations = attn_metadata.num_generations
num_ctx_tokens = attn_metadata.num_ctx_tokens
num_tokens = attn_metadata.num_tokens
assert q.shape[
0] == num_tokens, f"Expect q.shape[0] to be {num_tokens}, but got {q.shape[0]}"
if num_contexts > 0:
q_ctx = q[:num_ctx_tokens, ...]
compressed_kv_ctx = compressed_kv[:num_ctx_tokens, ...]
k_pe_ctx = k_pe[:num_ctx_tokens, ...]
attn_output_context = self.forward_context(q_ctx, compressed_kv_ctx,
k_pe_ctx, attn_metadata)
else:
attn_output_context = None
if num_generations > 0:
q_gen = q[num_ctx_tokens:, ...]
compressed_kv_gen = compressed_kv[num_ctx_tokens:, ...]
k_pe_gen = k_pe[num_ctx_tokens:, ...]
attn_output_gen = self.forward_generation(q_gen, compressed_kv_gen,
k_pe_gen, attn_metadata)
else:
attn_output_gen = None
# merge context and gen batches
if attn_output_context is not None and attn_output_gen is not None:
assert (
len(attn_output_context.shape) == 2
), f"attn_output_context must be rank 2, not {len(attn_output_context.shape)}"
assert (
len(attn_output_gen.shape) == 2
), f"attn_output_gen must be rank 2, not {len(attn_output_gen.shape)}"
attn_output = torch.cat([attn_output_context, attn_output_gen],
dim=0)
elif attn_output_gen is None:
attn_output = attn_output_context
else:
attn_output = attn_output_gen
attn_output = self.o_proj(attn_output,
all_reduce_params=all_reduce_params)
return attn_output
def forward_context(
self,
q: torch.Tensor,
compressed_kv: torch.Tensor,
k_pe: torch.Tensor,
attn_metadata: AttentionMetadata,
) -> torch.Tensor:
latent_cache = torch.cat([compressed_kv, k_pe], dim=-1)
kv = self.kv_b_proj(compressed_kv)
k_nope, v = kv.split(
[
self.num_heads * self.qk_nope_head_dim,
self.num_heads * self.v_head_dim
],
-1,
)
k = torch.empty_like(q).view(
-1, self.num_heads, (self.qk_nope_head_dim + self.qk_rope_head_dim))
k[..., :self.qk_nope_head_dim] = k_nope.view(-1, self.num_heads,
self.qk_nope_head_dim)
k = k.view(
-1,
self.num_heads * (self.qk_nope_head_dim + self.qk_rope_head_dim))
# Concat q(including q_pe), k + k_pe, v together as input_qkv
input_qkv = torch.cat([q, k, v], dim=-1)
out_scale = getattr(self.o_proj, "inv_input_scale", None)
attn_output = self.mha.forward(
input_qkv,
None,
None,
attn_metadata,
attention_input_type=AttentionInputType.context_only,
latent_cache=latent_cache,
out_scale=out_scale,
)
return attn_output
def forward_generation(
self,
q: torch.Tensor,
compressed_kv: torch.Tensor,
k_pe: torch.Tensor,
attn_metadata: AttentionMetadata,
) -> torch.Tensor:
num_tokens = q.shape[0]
latent_cache = torch.concat([compressed_kv, k_pe], dim=-1)
q_nope, q_pe = q.view([
-1, self.num_heads, self.qk_nope_head_dim + self.qk_rope_head_dim
]).split([self.qk_nope_head_dim, self.qk_rope_head_dim], dim=-1)
# fused_q contains 1) the result of the following bmm with shape [num_tokens, num_heads, kv_lora_rank]
# 2) rope(q_pe) with shape [num_tokens, num_heads, qk_rope_head_dim]. rope is applied inside AttentionOp
fused_q = torch.empty(
[
num_tokens, self.num_heads,
(self.kv_lora_rank + self.qk_rope_head_dim)
],
dtype=q.dtype,
device=q.device,
)
if self.k_b_proj_trans.dtype == torch.bfloat16:
# [num_heads, num_tokens, self.qk_nope_head_dim]
q_nope = q_nope.transpose(0, 1)
# [num_heads, num_tokens, self.kv_lora_rank]
q_nope_out = fused_q[..., :self.kv_lora_rank].transpose(0, 1)
# [num_heads, num_tokens, self.qk_nope_head_dim] x [num_heads, kv_lora_rank, qk_nope_head_dim]
# -> [num_heads, num_tokens, kv_lora_rank] -> [num_tokens, num_heads, kv_lora_rank]
# The output of bmm is written directly into fused_q
torch.ops.trtllm.bmm_out(q_nope,
self.k_b_proj_trans.transpose(1, 2),
q_nope_out)
elif self.k_b_proj_trans.dtype == torch.float8_e4m3fn:
q_nope, q_nope_scales = torch.ops.trtllm.fp8_batched_quantize_1x128_permute102(
q_nope)
# [num_heads, num_tokens, self.kv_lora_rank]
q_nope_out = fused_q[..., :self.kv_lora_rank].transpose(0, 1)
torch.ops.trtllm.fp8_block_scaling_bmm_out(
q_nope, self.k_b_proj_trans, q_nope_scales,
self.k_b_proj_trans_scale, q_nope_out)
else:
raise NotImplementedError(
f"Missing bmm impl for dtype: {self.k_b_proj_trans.dtype}.")
fused_q = fused_q.view([
num_tokens,
self.num_heads * (self.kv_lora_rank + self.qk_rope_head_dim)
])
out_scale = getattr(self.o_proj, "inv_input_scale", None)
attn_out_latent = self.mqa.forward(
fused_q,
None,
None,
attn_metadata,
attention_input_type=AttentionInputType.generation_only,
out_scale=out_scale,
latent_cache=latent_cache, # kvcache and k_pe
q_pe=q_pe, # used by `invokeMLARopeGeneration`
)
assert (attn_out_latent.shape[0] == q.shape[0] and
attn_out_latent.shape[1] == self.num_heads * self.kv_lora_rank)
# [seq, num_heads, kv_lora_rank]
attn_out_latent = attn_out_latent.view(
[-1, self.num_heads, self.kv_lora_rank])
attn_output = torch.empty([num_tokens, self.num_heads, self.v_head_dim],
dtype=attn_out_latent.dtype,
device=attn_out_latent.device)
if self.v_b_proj.dtype == torch.bfloat16:
# [num_heads, seq, kv_lora_rank] x [num_heads, kv_lora_rank, v_head_dim]
# -> [num_heads, seq, v_head_dim]
torch.ops.trtllm.bmm_out(attn_out_latent.transpose(0, 1),
self.v_b_proj.transpose(1, 2),
attn_output.transpose(0, 1))
elif self.v_b_proj.dtype == torch.float8_e4m3fn:
attn_out_latent, attn_out_latent_scales = torch.ops.trtllm.fp8_batched_quantize_1x128_permute102(
attn_out_latent)
torch.ops.trtllm.fp8_block_scaling_bmm_out(
attn_out_latent, self.v_b_proj, attn_out_latent_scales,
self.v_b_proj_scale, attn_output.transpose(0, 1))
else:
raise NotImplementedError(
f"Missing bmm impl for dtype: {self.v_b_proj.dtype}.")
# [seq, num_heads * v_head_dim]
attn_output_flatten = attn_output.flatten(1, 2)
return attn_output_flatten