Wan2.1/wan/modules/attention.py
2025-03-25 00:14:14 +01:00

390 lines
12 KiB
Python

# Copyright 2024-2025 The Alibaba Wan Team Authors. All rights reserved.
import torch
from importlib.metadata import version
from mmgp import offload
import torch.nn.functional as F
try:
import flash_attn_interface
FLASH_ATTN_3_AVAILABLE = True
except ModuleNotFoundError:
FLASH_ATTN_3_AVAILABLE = False
try:
import flash_attn
FLASH_ATTN_2_AVAILABLE = True
except ModuleNotFoundError:
FLASH_ATTN_2_AVAILABLE = False
flash_attn = None
try:
from sageattention import sageattn_varlen
def sageattn_varlen_wrapper(
q,
k,
v,
cu_seqlens_q,
cu_seqlens_kv,
max_seqlen_q,
max_seqlen_kv,
):
return sageattn_varlen(q, k, v, cu_seqlens_q, cu_seqlens_kv, max_seqlen_q, max_seqlen_kv)
except ImportError:
sageattn_varlen_wrapper = None
import warnings
try:
from sageattention import sageattn
from .sage2_core import sageattn as alt_sageattn, is_sage_supported
sage_supported = is_sage_supported()
except ImportError:
sageattn = None
alt_sageattn = None
sage_supported = False
# @torch.compiler.disable()
def sageattn_wrapper(
qkv_list,
attention_length
):
q,k, v = qkv_list
padding_length = q.shape[0] -attention_length
q = q[:attention_length, :, : ].unsqueeze(0)
k = k[:attention_length, :, : ].unsqueeze(0)
v = v[:attention_length, :, : ].unsqueeze(0)
if True:
qkv_list = [q,k,v]
del q, k ,v
o = alt_sageattn(qkv_list, tensor_layout="NHD").squeeze(0)
else:
o = sageattn(q, k, v, tensor_layout="NHD").squeeze(0)
del q, k ,v
qkv_list.clear()
if padding_length > 0:
o = torch.cat([o, torch.empty( (padding_length, *o.shape[-2:]), dtype= o.dtype, device=o.device ) ], 0)
return o
# # try:
# if True:
# from sageattention import sageattn_qk_int8_pv_fp8_window_cuda
# @torch.compiler.disable()
# def sageattn_window_wrapper(
# qkv_list,
# attention_length,
# window
# ):
# q,k, v = qkv_list
# padding_length = q.shape[0] -attention_length
# q = q[:attention_length, :, : ].unsqueeze(0)
# k = k[:attention_length, :, : ].unsqueeze(0)
# v = v[:attention_length, :, : ].unsqueeze(0)
# o = sageattn_qk_int8_pv_fp8_window_cuda(q, k, v, tensor_layout="NHD", window = window).squeeze(0)
# del q, k ,v
# qkv_list.clear()
# if padding_length > 0:
# o = torch.cat([o, torch.empty( (padding_length, *o.shape[-2:]), dtype= o.dtype, device=o.device ) ], 0)
# return o
# # except ImportError:
# # sageattn = sageattn_qk_int8_pv_fp8_window_cuda
@torch.compiler.disable()
def sdpa_wrapper(
qkv_list,
attention_length
):
q,k, v = qkv_list
padding_length = q.shape[0] -attention_length
q = q[:attention_length, :].transpose(0,1).unsqueeze(0)
k = k[:attention_length, :].transpose(0,1).unsqueeze(0)
v = v[:attention_length, :].transpose(0,1).unsqueeze(0)
o = F.scaled_dot_product_attention(
q, k, v, attn_mask=None, is_causal=False
).squeeze(0).transpose(0,1)
del q, k ,v
qkv_list.clear()
if padding_length > 0:
o = torch.cat([o, torch.empty( (padding_length, *o.shape[-2:]), dtype= o.dtype, device=o.device ) ], 0)
return o
def get_attention_modes():
ret = ["sdpa", "auto"]
if flash_attn != None:
ret.append("flash")
# if memory_efficient_attention != None:
# ret.append("xformers")
if sageattn_varlen_wrapper != None:
ret.append("sage")
if sageattn != None and version("sageattention").startswith("2") :
ret.append("sage2")
return ret
def get_supported_attention_modes():
ret = get_attention_modes()
if not sage_supported:
if "sage" in ret:
del ret["sage"]
if "sage2" in ret:
del ret["sage2"]
return ret
__all__ = [
'pay_attention',
'attention',
]
def pay_attention(
qkv_list,
# q,
# k,
# v,
q_lens=None,
k_lens=None,
dropout_p=0.,
softmax_scale=None,
q_scale=None,
causal=False,
window_size=(-1, -1),
deterministic=False,
dtype=torch.bfloat16,
version=None,
force_attention= None,
cross_attn= False
):
"""
q: [B, Lq, Nq, C1].
k: [B, Lk, Nk, C1].
v: [B, Lk, Nk, C2]. Nq must be divisible by Nk.
q_lens: [B].
k_lens: [B].
dropout_p: float. Dropout probability.
softmax_scale: float. The scaling of QK^T before applying softmax.
causal: bool. Whether to apply causal attention mask.
window_size: (left right). If not (-1, -1), apply sliding window local attention.
deterministic: bool. If True, slightly slower and uses more memory.
dtype: torch.dtype. Apply when dtype of q/k/v is not float16/bfloat16.
"""
attn = offload.shared_state["_attention"] if force_attention== None else force_attention
q,k,v = qkv_list
qkv_list.clear()
half_dtypes = (torch.float16, torch.bfloat16)
assert dtype in half_dtypes
assert q.device.type == 'cuda' and q.size(-1) <= 256
# params
b, lq, lk, out_dtype = q.size(0), q.size(1), k.size(1), q.dtype
def half(x):
return x if x.dtype in half_dtypes else x.to(dtype)
# preprocess query
if q_lens is None:
q = half(q.flatten(0, 1))
q_lens = torch.tensor(
[lq] * b, dtype=torch.int32).to(
device=q.device, non_blocking=True)
else:
q = half(torch.cat([u[:v] for u, v in zip(q, q_lens)]))
# preprocess key, value
if k_lens is None:
k = half(k.flatten(0, 1))
v = half(v.flatten(0, 1))
k_lens = torch.tensor(
[lk] * b, dtype=torch.int32).to(
device=k.device, non_blocking=True)
else:
k = half(torch.cat([u[:v] for u, v in zip(k, k_lens)]))
v = half(torch.cat([u[:v] for u, v in zip(v, k_lens)]))
q = q.to(v.dtype)
k = k.to(v.dtype)
if q_scale is not None:
q = q * q_scale
if version is not None and version == 3 and not FLASH_ATTN_3_AVAILABLE:
warnings.warn(
'Flash attention 3 is not available, use flash attention 2 instead.'
)
# apply attention
if attn=="sage":
x = sageattn_varlen_wrapper(
q=q,
k=k,
v=v,
cu_seqlens_q=torch.cat([q_lens.new_zeros([1]), q_lens]).cumsum(
0, dtype=torch.int32).to(q.device, non_blocking=True),
cu_seqlens_kv=torch.cat([k_lens.new_zeros([1]), k_lens]).cumsum(
0, dtype=torch.int32).to(q.device, non_blocking=True),
max_seqlen_q=lq,
max_seqlen_kv=lk,
).unflatten(0, (b, lq))
elif attn=="sage2":
import math
if cross_attn or True:
qkv_list = [q,k,v]
del q,k,v
x = sageattn_wrapper(qkv_list, lq).unsqueeze(0)
# else:
# layer = offload.shared_state["layer"]
# embed_sizes = offload.shared_state["embed_sizes"]
# current_step = offload.shared_state["step_no"]
# max_steps = offload.shared_state["max_steps"]
# nb_latents = embed_sizes[0] * embed_sizes[1]* embed_sizes[2]
# window = 0
# start_window_step = int(max_steps * 0.4)
# start_layer = 10
# if (layer < start_layer ) or current_step <start_window_step:
# window = 0
# else:
# coef = min((max_steps - current_step)/(max_steps-start_window_step),1)*max(min((25 - layer)/(25-start_layer),1),0) * 0.7 + 0.3
# print(f"step: {current_step}, layer: {layer}, coef:{coef:0.1f}]")
# window = math.ceil(coef* nb_latents)
# invert_spaces = (layer + current_step) % 2 == 0 and window > 0
# def flip(q):
# q = q.reshape(*embed_sizes, *q.shape[-2:])
# q = q.transpose(0,2)
# q = q.contiguous()
# q = q.transpose(0,2)
# q = q.reshape( -1, *q.shape[-2:])
# return q
# def flop(q):
# q = q.reshape(embed_sizes[2], embed_sizes[1], embed_sizes[0] , *q.shape[-2:])
# q = q.transpose(0,2)
# q = q.contiguous()
# q = q.transpose(0,2)
# q = q.reshape( -1, *q.shape[-2:])
# return q
# if invert_spaces:
# q = flip(q)
# k = flip(k)
# v = flip(v)
# qkv_list = [q,k,v]
# del q,k,v
# x = sageattn_window_wrapper(qkv_list, lq, window= window) #.unsqueeze(0)
# if invert_spaces:
# x = flop(x)
# x = x.unsqueeze(0)
elif attn=="sdpa":
qkv_list = [q, k, v]
del q, k , v
x = sdpa_wrapper( qkv_list, lq).unsqueeze(0)
elif attn=="flash" and version == 3:
# Note: dropout_p, window_size are not supported in FA3 now.
x = flash_attn_interface.flash_attn_varlen_func(
q=q,
k=k,
v=v,
cu_seqlens_q=torch.cat([q_lens.new_zeros([1]), q_lens]).cumsum(
0, dtype=torch.int32).to(q.device, non_blocking=True),
cu_seqlens_k=torch.cat([k_lens.new_zeros([1]), k_lens]).cumsum(
0, dtype=torch.int32).to(q.device, non_blocking=True),
seqused_q=None,
seqused_k=None,
max_seqlen_q=lq,
max_seqlen_k=lk,
softmax_scale=softmax_scale,
causal=causal,
deterministic=deterministic)[0].unflatten(0, (b, lq))
elif attn=="flash":
x = flash_attn.flash_attn_varlen_func(
q=q,
k=k,
v=v,
cu_seqlens_q=torch.cat([q_lens.new_zeros([1]), q_lens]).cumsum(
0, dtype=torch.int32).to(q.device, non_blocking=True),
cu_seqlens_k=torch.cat([k_lens.new_zeros([1]), k_lens]).cumsum(
0, dtype=torch.int32).to(q.device, non_blocking=True),
max_seqlen_q=lq,
max_seqlen_k=lk,
dropout_p=dropout_p,
softmax_scale=softmax_scale,
causal=causal,
window_size=window_size,
deterministic=deterministic).unflatten(0, (b, lq))
# output
return x.type(out_dtype)
def attention(
q,
k,
v,
q_lens=None,
k_lens=None,
dropout_p=0.,
softmax_scale=None,
q_scale=None,
causal=False,
window_size=(-1, -1),
deterministic=False,
dtype=torch.bfloat16,
fa_version=None,
):
if FLASH_ATTN_2_AVAILABLE or FLASH_ATTN_3_AVAILABLE:
return pay_attention(
q=q,
k=k,
v=v,
q_lens=q_lens,
k_lens=k_lens,
dropout_p=dropout_p,
softmax_scale=softmax_scale,
q_scale=q_scale,
causal=causal,
window_size=window_size,
deterministic=deterministic,
dtype=dtype,
version=fa_version,
)
else:
if q_lens is not None or k_lens is not None:
warnings.warn(
'Padding mask is disabled when using scaled_dot_product_attention. It can have a significant impact on performance.'
)
attn_mask = None
q = q.transpose(1, 2).to(dtype)
k = k.transpose(1, 2).to(dtype)
v = v.transpose(1, 2).to(dtype)
out = torch.nn.functional.scaled_dot_product_attention(
q, k, v, attn_mask=attn_mask, is_causal=causal, dropout_p=dropout_p)
out = out.transpose(1, 2).contiguous()
return out