refactor single card attention to no pad

This commit is contained in:
Peiyuan Zhang
2024-12-11 19:00:10 +00:00
parent 0d4ae825c9
commit f5074a5c31
4 changed files with 51 additions and 205 deletions
+24 -143
View File
@@ -11,142 +11,24 @@ from fastvideo.utils.communications import all_gather, all_to_all_4D
from fastvideo.utils.logging import ForkedPdb
from fastvideo.models.flash_attn_no_pad import flash_attn_no_pad
MEMORY_LAYOUT = {
"flash": (
lambda x: x.view(x.shape[0] * x.shape[1], *x.shape[2:]),
lambda x: x,
),
"torch": (
lambda x: x.transpose(1, 2),
lambda x: x.transpose(1, 2),
),
"vanilla": (
lambda x: x.transpose(1, 2),
lambda x: x.transpose(1, 2),
),
}
def get_cu_seqlens(text_mask, img_len):
"""Calculate cu_seqlens_q, cu_seqlens_kv using text_mask and img_len
Args:
text_mask (torch.Tensor): the mask of text
img_len (int): the length of image
Returns:
torch.Tensor: the calculated cu_seqlens for flash attention
"""
batch_size = text_mask.shape[0]
text_len = text_mask.sum(dim=1)
max_len = text_mask.shape[1] + img_len
cu_seqlens = torch.zeros([2 * batch_size + 1], dtype=torch.int32, device="cuda")
for i in range(batch_size):
s = text_len[i] + img_len
s1 = i * max_len + s
s2 = (i + 1) * max_len
cu_seqlens[2 * i + 1] = s1
cu_seqlens[2 * i + 2] = s2
return cu_seqlens
def attention(
q,
k,
v,
mode="flash",
drop_rate=0,
attn_mask=None,
causal=False,
cu_seqlens_q=None,
cu_seqlens_kv=None,
max_seqlen_q=None,
max_seqlen_kv=None,
batch_size=1,
):
"""
Perform QKV self attention.
Args:
q (torch.Tensor): Query tensor with shape [b, s, a, d], where a is the number of heads.
k (torch.Tensor): Key tensor with shape [b, s1, a, d]
v (torch.Tensor): Value tensor with shape [b, s1, a, d]
mode (str): Attention mode. Choose from 'self_flash', 'cross_flash', 'torch', and 'vanilla'.
drop_rate (float): Dropout rate in attention map. (default: 0)
attn_mask (torch.Tensor): Attention mask with shape [b, s1] (cross_attn), or [b, a, s, s1] (torch or vanilla).
(default: None)
causal (bool): Whether to use causal attention. (default: False)
cu_seqlens_q (torch.Tensor): dtype torch.int32. The cumulative sequence lengths of the sequences in the batch,
used to index into q.
cu_seqlens_kv (torch.Tensor): dtype torch.int32. The cumulative sequence lengths of the sequences in the batch,
used to index into kv.
max_seqlen_q (int): The maximum sequence length in the batch of q.
max_seqlen_kv (int): The maximum sequence length in the batch of k and v.
qkv = torch.stack([q, k, v], dim=2)
Returns:
torch.Tensor: Output tensor after self attention with shape [b, s, ad]
"""
pre_attn_layout, post_attn_layout = MEMORY_LAYOUT[mode]
q = pre_attn_layout(q)
k = pre_attn_layout(k)
v = pre_attn_layout(v)
if attn_mask is not None and attn_mask.dtype != torch.bool:
attn_mask = attn_mask.bool()
x = flash_attn_no_pad(qkv, attn_mask, causal=causal, dropout_p=drop_rate, softmax_scale=None)
if mode == "torch":
if attn_mask is not None and attn_mask.dtype != torch.bool:
attn_mask = attn_mask.to(q.dtype)
x = F.scaled_dot_product_attention(
q, k, v, attn_mask=attn_mask, dropout_p=drop_rate, is_causal=causal
)
elif mode == "flash":
x = flash_attn_varlen_func(
q,
k,
v,
cu_seqlens_q,
cu_seqlens_kv,
max_seqlen_q,
max_seqlen_kv,
)
# x with shape [(bxs), a, d]
x = x.view(
batch_size, max_seqlen_q, x.shape[-2], x.shape[-1]
) # reshape x to [b, s, a, d]
elif mode == "vanilla":
scale_factor = 1 / math.sqrt(q.size(-1))
b, a, s, _ = q.shape
s1 = k.size(2)
attn_bias = torch.zeros(b, a, s, s1, dtype=q.dtype, device=q.device)
if causal:
# Only applied to self attention
assert (
attn_mask is None
), "Causal mask and attn_mask cannot be used together"
temp_mask = torch.ones(b, a, s, s, dtype=torch.bool, device=q.device).tril(
diagonal=0
)
attn_bias.masked_fill_(temp_mask.logical_not(), float("-inf"))
attn_bias.to(q.dtype)
if attn_mask is not None:
if attn_mask.dtype == torch.bool:
attn_bias.masked_fill_(attn_mask.logical_not(), float("-inf"))
else:
attn_bias += attn_mask
# TODO: Maybe force q and k to be float32 to avoid numerical overflow
attn = (q @ k.transpose(-2, -1)) * scale_factor
attn += attn_bias
attn = attn.softmax(dim=-1)
attn = torch.dropout(attn, p=drop_rate, train=True)
x = attn @ v
else:
raise NotImplementedError(f"Unsupported attention mode: {mode}")
x = post_attn_layout(x)
b, s, a, d = x.shape
out = x.reshape(b, s, -1)
return out
@@ -165,8 +47,7 @@ def parallel_attention(
query, encoder_query = q[:, :img_q_len, :, :], q[:,img_q_len:]
key, encoder_key = k[:, :img_kv_len, :, :], k[:,img_kv_len:]
value, encoder_value = v[:, :img_kv_len, :, :], v[:,img_kv_len:]
if True:
if get_sequence_parallel_state():
# batch_size, seq_len, attn_heads, head_dim
query = all_to_all_4D(query, scatter_dim=2, gather_dim=1)
key = all_to_all_4D(key, scatter_dim=2, gather_dim=1)
@@ -180,27 +61,27 @@ def parallel_attention(
encoder_value = shrink_head(encoder_value, dim=2)
# [b, s, h, d]
sequence_length = query.size(1)
encoder_sequence_length = encoder_query.size(1)
sequence_length = query.size(1)
encoder_sequence_length = encoder_query.size(1)
# Hint: please check encoder_query.shape
query = torch.cat([query, encoder_query], dim=1)
key = torch.cat([key, encoder_key], dim=1)
value = torch.cat([value, encoder_value], dim=1)
# B, S, 3, H, D
qkv = torch.stack([query, key, value], dim=2)
attn_mask = F.pad(text_mask, (sequence_length, 0), value=True)
hidden_states = flash_attn_no_pad(qkv, attn_mask, causal=False, dropout_p=0.0, softmax_scale=None)
hidden_states, encoder_hidden_states = hidden_states.split_with_sizes(
(sequence_length, encoder_sequence_length), dim=1
)
# B, H, S, D
# Hint: please check encoder_query.shape
query = torch.cat([query, encoder_query], dim=1)
key = torch.cat([key, encoder_key], dim=1)
value = torch.cat([value, encoder_value], dim=1)
# B, S, 3, H, D
qkv = torch.stack([query, key, value], dim=2)
attn_mask = F.pad(text_mask, (sequence_length, 0), value=True)
hidden_states = flash_attn_no_pad(qkv, attn_mask, causal=False, dropout_p=0.0, softmax_scale=None)
hidden_states, encoder_hidden_states = hidden_states.split_with_sizes(
(sequence_length, encoder_sequence_length), dim=1
)
if get_sequence_parallel_state():
hidden_states = all_to_all_4D(hidden_states, scatter_dim=1, gather_dim=2)
encoder_hidden_states = all_gather(encoder_hidden_states, dim=2).contiguous()
hidden_states = hidden_states.to(query.dtype)
encoder_hidden_states = encoder_hidden_states.to(query.dtype)
hidden_states = hidden_states.to(query.dtype)
encoder_hidden_states = encoder_hidden_states.to(query.dtype)
attn = torch.cat([hidden_states, encoder_hidden_states], dim=1)
+21 -43
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@@ -11,7 +11,7 @@ from diffusers.configuration_utils import ConfigMixin, register_to_config
from .activation_layers import get_activation_layer
from .norm_layers import get_norm_layer
from .embed_layers import TimestepEmbedder, PatchEmbed, TextProjection
from .attenion import attention, parallel_attention, get_cu_seqlens
from .attenion import parallel_attention
from .posemb_layers import apply_rotary_emb
from .mlp_layers import MLP, MLPEmbedder, FinalLayer
from .modulate_layers import ModulateDiT, modulate, apply_gate
@@ -207,27 +207,16 @@ class MMDoubleStreamBlock(nn.Module):
k = torch.cat((img_k, txt_k), dim=1)
v = torch.cat((img_v, txt_v), dim=1)
# attention computation start
if nccl_info.sp_size > 1:
attn = parallel_attention(
q,
k,
v,
img_q_len=img_q.shape[1],
img_kv_len=img_k.shape[1],
text_mask=text_mask
)
else:
attn = attention(
q,
k,
v,
cu_seqlens_q=cu_seqlens_q,
cu_seqlens_kv=cu_seqlens_kv,
max_seqlen_q=max_seqlen_q,
max_seqlen_kv=max_seqlen_kv,
batch_size=img_k.shape[0],
)
attn = parallel_attention(
q,
k,
v,
img_q_len=img_q.shape[1],
img_kv_len=img_k.shape[1],
text_mask=text_mask
)
# attention computation end
@@ -371,27 +360,16 @@ class MMSingleStreamBlock(nn.Module):
# attention computation start
if nccl_info.sp_size > 1:
attn = parallel_attention(
q,
k,
v,
img_q_len=img_q.shape[1],
img_kv_len=img_k.shape[1],
text_mask=text_mask
)
else:
attn = attention(
q,
k,
v,
cu_seqlens_q=cu_seqlens_q,
cu_seqlens_kv=cu_seqlens_kv,
max_seqlen_q=max_seqlen_q,
max_seqlen_kv=max_seqlen_kv,
batch_size=x.shape[0],
)
attn = parallel_attention(
q,
k,
v,
img_q_len=img_q.shape[1],
img_kv_len=img_k.shape[1],
text_mask=text_mask
)
# attention computation end
@@ -90,7 +90,7 @@ class IndividualTokenRefinerBlock(nn.Module):
k = self.self_attn_k_norm(k).to(v)
# Self-Attention
attn = attention(q, k, v, mode="torch", attn_mask=attn_mask)
attn = attention(q, k, v, attn_mask=attn_mask)
x = x + apply_gate(self.self_attn_proj(attn), gate_msa)
@@ -140,24 +140,11 @@ class IndividualTokenRefiner(nn.Module):
c: torch.LongTensor,
mask: Optional[torch.Tensor] = None,
):
self_attn_mask = None
if mask is not None:
batch_size = mask.shape[0]
seq_len = mask.shape[1]
mask = mask.to(x.device)
# batch_size x 1 x seq_len x seq_len
self_attn_mask_1 = mask.view(batch_size, 1, 1, seq_len).repeat(
1, 1, seq_len, 1
)
# batch_size x 1 x seq_len x seq_len
self_attn_mask_2 = self_attn_mask_1.transpose(2, 3)
# batch_size x 1 x seq_len x seq_len, 1 for broadcasting of heads_num
self_attn_mask = (self_attn_mask_1 & self_attn_mask_2).bool()
# avoids self-attention weight being NaN for padding tokens
self_attn_mask[:, :, :, 0] = True
mask = mask.clone().bool()
# avoid attention weight become NaN
mask[:, 0] = True
for block in self.blocks:
x = block(x, c, self_attn_mask)
x = block(x, c, mask)
return x
+1 -1
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@@ -1,4 +1,4 @@
num_gpus=4
num_gpus=1
torchrun --nnodes=1 --nproc_per_node=$num_gpus --master_port 29503 \
fastvideo/sample/sample_t2v_hunyuan.py \