wangbo/ComfyUI
1
0
Fork 0
mirror of https://github.com/comfyanonymous/ComfyUI.git synced 2026-03-16 22:58:19 +08:00
Code Issues Actions 11 Packages Projects Releases Wiki Activity
385221234c
ComfyUI/comfy/ldm/wan/vae2_2.py
ReinerBforartists 385221234c Fixes mutable default arguments in the wan vae. 
In Python, mutable default arguments are evaluated **once at function definition time** and shared across all subsequent calls. This is a well-known Python pitfall:

```python
# BAD: this list is shared across ALL calls to forward()
def forward(self, x, feat_cache=None, feat_idx=[0]):
    feat_idx[0] += 1  # modifies the shared default list!
```

In `comfy/ldm/wan/vae.py` and `comfy/ldm/wan/vae2_2.py`, the `forward` methods of `Resample`, `ResidualBlock`, `Down_ResidualBlock`, `Up_ResidualBlock`, `Encoder3d` and `Decoder3d` all use `feat_idx=[0]` as a default argument. Since `feat_idx[0]` is incremented inside these methods, the default value accumulates between inference runs. On the second run, `feat_idx[0]` no longer starts at `0` but at whatever value it reached at the end of the first run, causing incorrect cache indexing throughout the entire encoder and decoder.

**Fix:**

```python
# GOOD: a new list is created for every call that doesn't pass feat_idx
def forward(self, x, feat_cache=None, feat_idx=None):
    # Fix: mutable default argument feat_idx=[0] would persist between calls
    if feat_idx is None:
        feat_idx = [0]
```

**Observed impact:** On AMD/ROCm hardware this bug caused 4-5x slower inference on all runs after the first with WAN VAE. After this fix, only Run 2 remains slightly slower (due to a separate MIOpen kernel cache issue), while Run 3 and beyond are now as fast as Run 1. The bug likely affects all hardware to some degree as incorrect cache indexing causes unnecessary recomputation.

Related issues exists in the ROCm tracker and in the ComfyUI tracker.

https://github.com/ROCm/ROCm/issues/6008
https://github.com/Comfy-Org/ComfyUI/issues/12672#issuecomment-4059981039
2026-03-14 09:57:05 +01:00

735 lines
23 KiB
Python
Raw Blame History

# original version: https://github.com/Wan-Video/Wan2.2/blob/main/wan/modules/vae2_2.py
# Copyright 2024-2025 The Alibaba Wan Team Authors. All rights reserved.
import torch
import torch.nn as nn
import torch.nn.functional as F
from einops import rearrange
from .vae import AttentionBlock, CausalConv3d, RMS_norm
import comfy.ops
ops = comfy.ops.disable_weight_init
CACHE_T = 2
class Resample(nn.Module):
def __init__(self, dim, mode):
assert mode in (
"none",
"upsample2d",
"upsample3d",
"downsample2d",
"downsample3d",
)
super().__init__()
self.dim = dim
self.mode = mode
# layers
if mode == "upsample2d":
self.resample = nn.Sequential(
nn.Upsample(scale_factor=(2.0, 2.0), mode="nearest-exact"),
ops.Conv2d(dim, dim, 3, padding=1),
)
elif mode == "upsample3d":
self.resample = nn.Sequential(
nn.Upsample(scale_factor=(2.0, 2.0), mode="nearest-exact"),
ops.Conv2d(dim, dim, 3, padding=1),
# ops.Conv2d(dim, dim//2, 3, padding=1)
)
self.time_conv = CausalConv3d(
dim, dim * 2, (3, 1, 1), padding=(1, 0, 0))
elif mode == "downsample2d":
self.resample = nn.Sequential(
nn.ZeroPad2d((0, 1, 0, 1)),
ops.Conv2d(dim, dim, 3, stride=(2, 2)))
elif mode == "downsample3d":
self.resample = nn.Sequential(
nn.ZeroPad2d((0, 1, 0, 1)),
ops.Conv2d(dim, dim, 3, stride=(2, 2)))
self.time_conv = CausalConv3d(
dim, dim, (3, 1, 1), stride=(2, 1, 1), padding=(0, 0, 0))
else:
self.resample = nn.Identity()
# Fix: mutable default argument feat_idx=[0] would persist between calls
def forward(self, x, feat_cache=None, feat_idx=None):
if feat_idx is None:
feat_idx = [0]
b, c, t, h, w = x.size()
if self.mode == "upsample3d":
if feat_cache is not None:
idx = feat_idx[0]
if feat_cache[idx] is None:
feat_cache[idx] = "Rep"
feat_idx[0] += 1
else:
cache_x = x[:, :, -CACHE_T:, :, :].clone()
if (cache_x.shape[2] < 2 and feat_cache[idx] is not None and
feat_cache[idx] != "Rep"):
# cache last frame of last two chunk
cache_x = torch.cat(
[
feat_cache[idx][:, :, -1, :, :].unsqueeze(2).to(
cache_x.device),
cache_x,
],
dim=2,
)
if (cache_x.shape[2] < 2 and feat_cache[idx] is not None and
feat_cache[idx] == "Rep"):
cache_x = torch.cat(
[
torch.zeros_like(cache_x).to(cache_x.device),
cache_x
],
dim=2,
)
if feat_cache[idx] == "Rep":
x = self.time_conv(x)
else:
x = self.time_conv(x, feat_cache[idx])
feat_cache[idx] = cache_x
feat_idx[0] += 1
x = x.reshape(b, 2, c, t, h, w)
x = torch.stack((x[:, 0, :, :, :, :], x[:, 1, :, :, :, :]),
3)
x = x.reshape(b, c, t * 2, h, w)
t = x.shape[2]
x = rearrange(x, "b c t h w -> (b t) c h w")
x = self.resample(x)
x = rearrange(x, "(b t) c h w -> b c t h w", t=t)
if self.mode == "downsample3d":
if feat_cache is not None:
idx = feat_idx[0]
if feat_cache[idx] is None:
feat_cache[idx] = x.clone()
feat_idx[0] += 1
else:
cache_x = x[:, :, -1:, :, :].clone()
x = self.time_conv(
torch.cat([feat_cache[idx][:, :, -1:, :, :], x], 2))
feat_cache[idx] = cache_x
feat_idx[0] += 1
return x
class ResidualBlock(nn.Module):
def __init__(self, in_dim, out_dim, dropout=0.0):
super().__init__()
self.in_dim = in_dim
self.out_dim = out_dim
# layers
self.residual = nn.Sequential(
RMS_norm(in_dim, images=False),
nn.SiLU(),
CausalConv3d(in_dim, out_dim, 3, padding=1),
RMS_norm(out_dim, images=False),
nn.SiLU(),
nn.Dropout(dropout),
CausalConv3d(out_dim, out_dim, 3, padding=1),
)
self.shortcut = (
CausalConv3d(in_dim, out_dim, 1)
if in_dim != out_dim else nn.Identity())
# Fix: mutable default argument feat_idx=[0] would persist between calls
def forward(self, x, feat_cache=None, feat_idx=None):
if feat_idx is None:
feat_idx = [0]
old_x = x
for layer in self.residual:
if isinstance(layer, CausalConv3d) and feat_cache is not None:
idx = feat_idx[0]
cache_x = x[:, :, -CACHE_T:, :, :].clone()
if cache_x.shape[2] < 2 and feat_cache[idx] is not None:
# cache last frame of last two chunk
cache_x = torch.cat(
[
feat_cache[idx][:, :, -1, :, :].unsqueeze(2).to(
cache_x.device),
cache_x,
],
dim=2,
)
x = layer(x, cache_list=feat_cache, cache_idx=idx)
feat_cache[idx] = cache_x
feat_idx[0] += 1
else:
x = layer(x)
return x + self.shortcut(old_x)
def patchify(x, patch_size):
if patch_size == 1:
return x
if x.dim() == 4:
x = rearrange(
x, "b c (h q) (w r) -> b (c r q) h w", q=patch_size, r=patch_size)
elif x.dim() == 5:
x = rearrange(
x,
"b c f (h q) (w r) -> b (c r q) f h w",
q=patch_size,
r=patch_size,
)
else:
raise ValueError(f"Invalid input shape: {x.shape}")
return x
def unpatchify(x, patch_size):
if patch_size == 1:
return x
if x.dim() == 4:
x = rearrange(
x, "b (c r q) h w -> b c (h q) (w r)", q=patch_size, r=patch_size)
elif x.dim() == 5:
x = rearrange(
x,
"b (c r q) f h w -> b c f (h q) (w r)",
q=patch_size,
r=patch_size,
)
return x
class AvgDown3D(nn.Module):
def __init__(
self,
in_channels,
out_channels,
factor_t,
factor_s=1,
):
super().__init__()
self.in_channels = in_channels
self.out_channels = out_channels
self.factor_t = factor_t
self.factor_s = factor_s
self.factor = self.factor_t * self.factor_s * self.factor_s
assert in_channels * self.factor % out_channels == 0
self.group_size = in_channels * self.factor // out_channels
def forward(self, x: torch.Tensor) -> torch.Tensor:
pad_t = (self.factor_t - x.shape[2] % self.factor_t) % self.factor_t
pad = (0, 0, 0, 0, pad_t, 0)
x = F.pad(x, pad)
B, C, T, H, W = x.shape
x = x.view(
B,
C,
T // self.factor_t,
self.factor_t,
H // self.factor_s,
self.factor_s,
W // self.factor_s,
self.factor_s,
)
x = x.permute(0, 1, 3, 5, 7, 2, 4, 6).contiguous()
x = x.view(
B,
C * self.factor,
T // self.factor_t,
H // self.factor_s,
W // self.factor_s,
)
x = x.view(
B,
self.out_channels,
self.group_size,
T // self.factor_t,
H // self.factor_s,
W // self.factor_s,
)
x = x.mean(dim=2)
return x
class DupUp3D(nn.Module):
def __init__(
self,
in_channels: int,
out_channels: int,
factor_t,
factor_s=1,
):
super().__init__()
self.in_channels = in_channels
self.out_channels = out_channels
self.factor_t = factor_t
self.factor_s = factor_s
self.factor = self.factor_t * self.factor_s * self.factor_s
assert out_channels * self.factor % in_channels == 0
self.repeats = out_channels * self.factor // in_channels
def forward(self, x: torch.Tensor, first_chunk=False) -> torch.Tensor:
x = x.repeat_interleave(self.repeats, dim=1)
x = x.view(
x.size(0),
self.out_channels,
self.factor_t,
self.factor_s,
self.factor_s,
x.size(2),
x.size(3),
x.size(4),
)
x = x.permute(0, 1, 5, 2, 6, 3, 7, 4).contiguous()
x = x.view(
x.size(0),
self.out_channels,
x.size(2) * self.factor_t,
x.size(4) * self.factor_s,
x.size(6) * self.factor_s,
)
if first_chunk:
x = x[:, :, self.factor_t - 1:, :, :]
return x
class Down_ResidualBlock(nn.Module):
def __init__(self,
in_dim,
out_dim,
dropout,
mult,
temperal_downsample=False,
down_flag=False):
super().__init__()
# Shortcut path with downsample
self.avg_shortcut = AvgDown3D(
in_dim,
out_dim,
factor_t=2 if temperal_downsample else 1,
factor_s=2 if down_flag else 1,
)
# Main path with residual blocks and downsample
downsamples = []
for _ in range(mult):
downsamples.append(ResidualBlock(in_dim, out_dim, dropout))
in_dim = out_dim
# Add the final downsample block
if down_flag:
mode = "downsample3d" if temperal_downsample else "downsample2d"
downsamples.append(Resample(out_dim, mode=mode))
self.downsamples = nn.Sequential(*downsamples)
# Fix: mutable default argument feat_idx=[0] would persist between calls
def forward(self, x, feat_cache=None, feat_idx=None):
if feat_idx is None:
feat_idx = [0]
x_copy = x
for module in self.downsamples:
x = module(x, feat_cache, feat_idx)
return x + self.avg_shortcut(x_copy)
class Up_ResidualBlock(nn.Module):
def __init__(self,
in_dim,
out_dim,
dropout,
mult,
temperal_upsample=False,
up_flag=False):
super().__init__()
# Shortcut path with upsample
if up_flag:
self.avg_shortcut = DupUp3D(
in_dim,
out_dim,
factor_t=2 if temperal_upsample else 1,
factor_s=2 if up_flag else 1,
)
else:
self.avg_shortcut = None
# Main path with residual blocks and upsample
upsamples = []
for _ in range(mult):
upsamples.append(ResidualBlock(in_dim, out_dim, dropout))
in_dim = out_dim
# Add the final upsample block
if up_flag:
mode = "upsample3d" if temperal_upsample else "upsample2d"
upsamples.append(Resample(out_dim, mode=mode))
self.upsamples = nn.Sequential(*upsamples)
# Fix: mutable default argument feat_idx=[0] would persist between calls
def forward(self, x, feat_cache=None, feat_idx=None, first_chunk=False):
if feat_idx is None:
feat_idx = [0]
x_main = x
for module in self.upsamples:
x_main = module(x_main, feat_cache, feat_idx)
if self.avg_shortcut is not None:
x_shortcut = self.avg_shortcut(x, first_chunk)
return x_main + x_shortcut
else:
return x_main
class Encoder3d(nn.Module):
def __init__(
self,
dim=128,
z_dim=4,
dim_mult=[1, 2, 4, 4],
num_res_blocks=2,
attn_scales=[],
temperal_downsample=[True, True, False],
dropout=0.0,
):
super().__init__()
self.dim = dim
self.z_dim = z_dim
self.dim_mult = dim_mult
self.num_res_blocks = num_res_blocks
self.attn_scales = attn_scales
self.temperal_downsample = temperal_downsample
# dimensions
dims = [dim * u for u in [1] + dim_mult]
scale = 1.0
# init block
self.conv1 = CausalConv3d(12, dims[0], 3, padding=1)
# downsample blocks
downsamples = []
for i, (in_dim, out_dim) in enumerate(zip(dims[:-1], dims[1:])):
t_down_flag = (
temperal_downsample[i]
if i < len(temperal_downsample) else False)
downsamples.append(
Down_ResidualBlock(
in_dim=in_dim,
out_dim=out_dim,
dropout=dropout,
mult=num_res_blocks,
temperal_downsample=t_down_flag,
down_flag=i != len(dim_mult) - 1,
))
scale /= 2.0
self.downsamples = nn.Sequential(*downsamples)
# middle blocks
self.middle = nn.Sequential(
ResidualBlock(out_dim, out_dim, dropout),
AttentionBlock(out_dim),
ResidualBlock(out_dim, out_dim, dropout),
)
# # output blocks
self.head = nn.Sequential(
RMS_norm(out_dim, images=False),
nn.SiLU(),
CausalConv3d(out_dim, z_dim, 3, padding=1),
)
# Fix: mutable default argument feat_idx=[0] would persist between calls
def forward(self, x, feat_cache=None, feat_idx=None):
if feat_idx is None:
feat_idx = [0]
if feat_cache is not None:
idx = feat_idx[0]
cache_x = x[:, :, -CACHE_T:, :, :].clone()
if cache_x.shape[2] < 2 and feat_cache[idx] is not None:
cache_x = torch.cat(
[
feat_cache[idx][:, :, -1, :, :].unsqueeze(2).to(
cache_x.device),
cache_x,
],
dim=2,
)
x = self.conv1(x, feat_cache[idx])
feat_cache[idx] = cache_x
feat_idx[0] += 1
else:
x = self.conv1(x)
## downsamples
for layer in self.downsamples:
if feat_cache is not None:
x = layer(x, feat_cache, feat_idx)
else:
x = layer(x)
## middle
for layer in self.middle:
if isinstance(layer, ResidualBlock) and feat_cache is not None:
x = layer(x, feat_cache, feat_idx)
else:
x = layer(x)
## head
for layer in self.head:
if isinstance(layer, CausalConv3d) and feat_cache is not None:
idx = feat_idx[0]
cache_x = x[:, :, -CACHE_T:, :, :].clone()
if cache_x.shape[2] < 2 and feat_cache[idx] is not None:
cache_x = torch.cat(
[
feat_cache[idx][:, :, -1, :, :].unsqueeze(2).to(
cache_x.device),
cache_x,
],
dim=2,
)
x = layer(x, feat_cache[idx])
feat_cache[idx] = cache_x
feat_idx[0] += 1
else:
x = layer(x)
return x
class Decoder3d(nn.Module):
def __init__(
self,
dim=128,
z_dim=4,
dim_mult=[1, 2, 4, 4],
num_res_blocks=2,
attn_scales=[],
temperal_upsample=[False, True, True],
dropout=0.0,
):
super().__init__()
self.dim = dim
self.z_dim = z_dim
self.dim_mult = dim_mult
self.num_res_blocks = num_res_blocks
self.attn_scales = attn_scales
self.temperal_upsample = temperal_upsample
# dimensions
dims = [dim * u for u in [dim_mult[-1]] + dim_mult[::-1]]
# init block
self.conv1 = CausalConv3d(z_dim, dims[0], 3, padding=1)
# middle blocks
self.middle = nn.Sequential(
ResidualBlock(dims[0], dims[0], dropout),
AttentionBlock(dims[0]),
ResidualBlock(dims[0], dims[0], dropout),
)
# upsample blocks
upsamples = []
for i, (in_dim, out_dim) in enumerate(zip(dims[:-1], dims[1:])):
t_up_flag = temperal_upsample[i] if i < len(
temperal_upsample) else False
upsamples.append(
Up_ResidualBlock(
in_dim=in_dim,
out_dim=out_dim,
dropout=dropout,
mult=num_res_blocks + 1,
temperal_upsample=t_up_flag,
up_flag=i != len(dim_mult) - 1,
))
self.upsamples = nn.Sequential(*upsamples)
# output blocks
self.head = nn.Sequential(
RMS_norm(out_dim, images=False),
nn.SiLU(),
CausalConv3d(out_dim, 12, 3, padding=1),
)
# Fix: mutable default argument feat_idx=[0] would persist between calls
def forward(self, x, feat_cache=None, feat_idx=None, first_chunk=False):
if feat_idx is None:
feat_idx = [0]
if feat_cache is not None:
idx = feat_idx[0]
cache_x = x[:, :, -CACHE_T:, :, :].clone()
if cache_x.shape[2] < 2 and feat_cache[idx] is not None:
cache_x = torch.cat(
[
feat_cache[idx][:, :, -1, :, :].unsqueeze(2).to(
cache_x.device),
cache_x,
],
dim=2,
)
x = self.conv1(x, feat_cache[idx])
feat_cache[idx] = cache_x
feat_idx[0] += 1
else:
x = self.conv1(x)
for layer in self.middle:
if isinstance(layer, ResidualBlock) and feat_cache is not None:
x = layer(x, feat_cache, feat_idx)
else:
x = layer(x)
## upsamples
for layer in self.upsamples:
if feat_cache is not None:
x = layer(x, feat_cache, feat_idx, first_chunk)
else:
x = layer(x)
## head
for layer in self.head:
if isinstance(layer, CausalConv3d) and feat_cache is not None:
idx = feat_idx[0]
cache_x = x[:, :, -CACHE_T:, :, :].clone()
if cache_x.shape[2] < 2 and feat_cache[idx] is not None:
cache_x = torch.cat(
[
feat_cache[idx][:, :, -1, :, :].unsqueeze(2).to(
cache_x.device),
cache_x,
],
dim=2,
)
x = layer(x, feat_cache[idx])
feat_cache[idx] = cache_x
feat_idx[0] += 1
else:
x = layer(x)
return x
def count_conv3d(model):
count = 0
for m in model.modules():
if isinstance(m, CausalConv3d):
count += 1
return count
class WanVAE(nn.Module):
def __init__(
self,
dim=160,
dec_dim=256,
z_dim=16,
dim_mult=[1, 2, 4, 4],
num_res_blocks=2,
attn_scales=[],
temperal_downsample=[True, True, False],
dropout=0.0,
):
super().__init__()
self.dim = dim
self.z_dim = z_dim
self.dim_mult = dim_mult
self.num_res_blocks = num_res_blocks
self.attn_scales = attn_scales
self.temperal_downsample = temperal_downsample
self.temperal_upsample = temperal_downsample[::-1]
# modules
self.encoder = Encoder3d(
dim,
z_dim * 2,
dim_mult,
num_res_blocks,
attn_scales,
self.temperal_downsample,
dropout,
)
self.conv1 = CausalConv3d(z_dim * 2, z_dim * 2, 1)
self.conv2 = CausalConv3d(z_dim, z_dim, 1)
self.decoder = Decoder3d(
dec_dim,
z_dim,
dim_mult,
num_res_blocks,
attn_scales,
self.temperal_upsample,
dropout,
)
def encode(self, x):
conv_idx = [0]
feat_map = [None] * count_conv3d(self.encoder)
x = patchify(x, patch_size=2)
t = x.shape[2]
iter_ = 1 + (t - 1) // 4
for i in range(iter_):
conv_idx = [0]
if i == 0:
out = self.encoder(
x[:, :, :1, :, :],
feat_cache=feat_map,
feat_idx=conv_idx,
)
else:
out_ = self.encoder(
x[:, :, 1 + 4 * (i - 1):1 + 4 * i, :, :],
feat_cache=feat_map,
feat_idx=conv_idx,
)
out = torch.cat([out, out_], 2)
mu, log_var = self.conv1(out).chunk(2, dim=1)
return mu
def decode(self, z):
conv_idx = [0]
feat_map = [None] * count_conv3d(self.decoder)
iter_ = z.shape[2]
x = self.conv2(z)
for i in range(iter_):
conv_idx = [0]
if i == 0:
out = self.decoder(
x[:, :, i:i + 1, :, :],
feat_cache=feat_map,
feat_idx=conv_idx,
first_chunk=True,
)
else:
out_ = self.decoder(
x[:, :, i:i + 1, :, :],
feat_cache=feat_map,
feat_idx=conv_idx,
)
out = torch.cat([out, out_], 2)
out = unpatchify(out, patch_size=2)
return out
def reparameterize(self, mu, log_var):
std = torch.exp(0.5 * log_var)
eps = torch.randn_like(std)
return eps * std + mu
def sample(self, imgs, deterministic=False):
mu, log_var = self.encode(imgs)
if deterministic:
return mu
std = torch.exp(0.5 * log_var.clamp(-30.0, 20.0))
return mu + std * torch.randn_like(std)
Reference in New Issue View Git Blame Copy Permalink