ComfyUI/comfy/ops.py
User 1ce987cf52 Fix Python 3.12 VRAM spikes with CUDNN benchmark
Disables torch.backends.cudnn.benchmark on Python 3.12 to prevent
severe VRAM allocation spikes that occur during model operations.

The CUDNN benchmarking feature, introduced in v0.3.57 (commit e2d1e5da),
tests multiple convolution algorithms and allocates temporary VRAM.
This interacts poorly with Python 3.12's garbage collection behavior,
causing multi-GB VRAM spikes before and after model inference.

Solution:
- Preserves CUDNN benchmarking performance benefit on other Python versions
- Only disables the problematic behavior on Python 3.12
- Maintains full functionality while fixing memory management issues
- No impact on users not using --fast autotune flag

Tested with TTS model wrappers that reproduce the issue consistently
on Python 3.12 with ComfyUI v0.3.57+.

Fixes: VRAM spikes in Python 3.12 environments
Related: ComfyUI v0.3.57 regression affecting model memory management
2025-09-26 00:53:47 -03:00

475 lines
18 KiB
Python

"""
This file is part of ComfyUI.
Copyright (C) 2024 Stability AI
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
"""
import torch
import logging
import comfy.model_management
from comfy.cli_args import args, PerformanceFeature
import comfy.float
import comfy.rmsnorm
import contextlib
def scaled_dot_product_attention(q, k, v, *args, **kwargs):
return torch.nn.functional.scaled_dot_product_attention(q, k, v, *args, **kwargs)
try:
if torch.cuda.is_available():
from torch.nn.attention import SDPBackend, sdpa_kernel
import inspect
if "set_priority" in inspect.signature(sdpa_kernel).parameters:
SDPA_BACKEND_PRIORITY = [
SDPBackend.FLASH_ATTENTION,
SDPBackend.EFFICIENT_ATTENTION,
SDPBackend.MATH,
]
SDPA_BACKEND_PRIORITY.insert(0, SDPBackend.CUDNN_ATTENTION)
def scaled_dot_product_attention(q, k, v, *args, **kwargs):
with sdpa_kernel(SDPA_BACKEND_PRIORITY, set_priority=True):
return torch.nn.functional.scaled_dot_product_attention(q, k, v, *args, **kwargs)
else:
logging.warning("Torch version too old to set sdpa backend priority.")
except (ModuleNotFoundError, TypeError):
logging.warning("Could not set sdpa backend priority.")
cast_to = comfy.model_management.cast_to #TODO: remove once no more references
if torch.cuda.is_available() and torch.backends.cudnn.is_available() and PerformanceFeature.AutoTune in args.fast:
import sys
# Skip CUDNN benchmark on Python 3.12 due to VRAM allocation issues with model wrappers
if sys.version_info[:2] != (3, 12):
torch.backends.cudnn.benchmark = True
def cast_to_input(weight, input, non_blocking=False, copy=True):
return comfy.model_management.cast_to(weight, input.dtype, input.device, non_blocking=non_blocking, copy=copy)
def cast_bias_weight(s, input=None, dtype=None, device=None, bias_dtype=None):
if input is not None:
if dtype is None:
dtype = input.dtype
if bias_dtype is None:
bias_dtype = dtype
if device is None:
device = input.device
offload_stream = comfy.model_management.get_offload_stream(device)
if offload_stream is not None:
wf_context = offload_stream
else:
wf_context = contextlib.nullcontext()
bias = None
non_blocking = comfy.model_management.device_supports_non_blocking(device)
if s.bias is not None:
has_function = len(s.bias_function) > 0
bias = comfy.model_management.cast_to(s.bias, bias_dtype, device, non_blocking=non_blocking, copy=has_function, stream=offload_stream)
if has_function:
with wf_context:
for f in s.bias_function:
bias = f(bias)
has_function = len(s.weight_function) > 0
weight = comfy.model_management.cast_to(s.weight, dtype, device, non_blocking=non_blocking, copy=has_function, stream=offload_stream)
if has_function:
with wf_context:
for f in s.weight_function:
weight = f(weight)
comfy.model_management.sync_stream(device, offload_stream)
return weight, bias
class CastWeightBiasOp:
comfy_cast_weights = False
weight_function = []
bias_function = []
class disable_weight_init:
class Linear(torch.nn.Linear, CastWeightBiasOp):
def reset_parameters(self):
return None
def forward_comfy_cast_weights(self, input):
weight, bias = cast_bias_weight(self, input)
return torch.nn.functional.linear(input, weight, bias)
def forward(self, *args, **kwargs):
if self.comfy_cast_weights or len(self.weight_function) > 0 or len(self.bias_function) > 0:
return self.forward_comfy_cast_weights(*args, **kwargs)
else:
return super().forward(*args, **kwargs)
class Conv1d(torch.nn.Conv1d, CastWeightBiasOp):
def reset_parameters(self):
return None
def forward_comfy_cast_weights(self, input):
weight, bias = cast_bias_weight(self, input)
return self._conv_forward(input, weight, bias)
def forward(self, *args, **kwargs):
if self.comfy_cast_weights or len(self.weight_function) > 0 or len(self.bias_function) > 0:
return self.forward_comfy_cast_weights(*args, **kwargs)
else:
return super().forward(*args, **kwargs)
class Conv2d(torch.nn.Conv2d, CastWeightBiasOp):
def reset_parameters(self):
return None
def forward_comfy_cast_weights(self, input):
weight, bias = cast_bias_weight(self, input)
return self._conv_forward(input, weight, bias)
def forward(self, *args, **kwargs):
if self.comfy_cast_weights or len(self.weight_function) > 0 or len(self.bias_function) > 0:
return self.forward_comfy_cast_weights(*args, **kwargs)
else:
return super().forward(*args, **kwargs)
class Conv3d(torch.nn.Conv3d, CastWeightBiasOp):
def reset_parameters(self):
return None
def forward_comfy_cast_weights(self, input):
weight, bias = cast_bias_weight(self, input)
return self._conv_forward(input, weight, bias)
def forward(self, *args, **kwargs):
if self.comfy_cast_weights or len(self.weight_function) > 0 or len(self.bias_function) > 0:
return self.forward_comfy_cast_weights(*args, **kwargs)
else:
return super().forward(*args, **kwargs)
class GroupNorm(torch.nn.GroupNorm, CastWeightBiasOp):
def reset_parameters(self):
return None
def forward_comfy_cast_weights(self, input):
weight, bias = cast_bias_weight(self, input)
return torch.nn.functional.group_norm(input, self.num_groups, weight, bias, self.eps)
def forward(self, *args, **kwargs):
if self.comfy_cast_weights or len(self.weight_function) > 0 or len(self.bias_function) > 0:
return self.forward_comfy_cast_weights(*args, **kwargs)
else:
return super().forward(*args, **kwargs)
class LayerNorm(torch.nn.LayerNorm, CastWeightBiasOp):
def reset_parameters(self):
return None
def forward_comfy_cast_weights(self, input):
if self.weight is not None:
weight, bias = cast_bias_weight(self, input)
else:
weight = None
bias = None
return torch.nn.functional.layer_norm(input, self.normalized_shape, weight, bias, self.eps)
def forward(self, *args, **kwargs):
if self.comfy_cast_weights or len(self.weight_function) > 0 or len(self.bias_function) > 0:
return self.forward_comfy_cast_weights(*args, **kwargs)
else:
return super().forward(*args, **kwargs)
class RMSNorm(comfy.rmsnorm.RMSNorm, CastWeightBiasOp):
def reset_parameters(self):
self.bias = None
return None
def forward_comfy_cast_weights(self, input):
if self.weight is not None:
weight, bias = cast_bias_weight(self, input)
else:
weight = None
return comfy.rmsnorm.rms_norm(input, weight, self.eps) # TODO: switch to commented out line when old torch is deprecated
# return torch.nn.functional.rms_norm(input, self.normalized_shape, weight, self.eps)
def forward(self, *args, **kwargs):
if self.comfy_cast_weights or len(self.weight_function) > 0 or len(self.bias_function) > 0:
return self.forward_comfy_cast_weights(*args, **kwargs)
else:
return super().forward(*args, **kwargs)
class ConvTranspose2d(torch.nn.ConvTranspose2d, CastWeightBiasOp):
def reset_parameters(self):
return None
def forward_comfy_cast_weights(self, input, output_size=None):
num_spatial_dims = 2
output_padding = self._output_padding(
input, output_size, self.stride, self.padding, self.kernel_size,
num_spatial_dims, self.dilation)
weight, bias = cast_bias_weight(self, input)
return torch.nn.functional.conv_transpose2d(
input, weight, bias, self.stride, self.padding,
output_padding, self.groups, self.dilation)
def forward(self, *args, **kwargs):
if self.comfy_cast_weights or len(self.weight_function) > 0 or len(self.bias_function) > 0:
return self.forward_comfy_cast_weights(*args, **kwargs)
else:
return super().forward(*args, **kwargs)
class ConvTranspose1d(torch.nn.ConvTranspose1d, CastWeightBiasOp):
def reset_parameters(self):
return None
def forward_comfy_cast_weights(self, input, output_size=None):
num_spatial_dims = 1
output_padding = self._output_padding(
input, output_size, self.stride, self.padding, self.kernel_size,
num_spatial_dims, self.dilation)
weight, bias = cast_bias_weight(self, input)
return torch.nn.functional.conv_transpose1d(
input, weight, bias, self.stride, self.padding,
output_padding, self.groups, self.dilation)
def forward(self, *args, **kwargs):
if self.comfy_cast_weights or len(self.weight_function) > 0 or len(self.bias_function) > 0:
return self.forward_comfy_cast_weights(*args, **kwargs)
else:
return super().forward(*args, **kwargs)
class Embedding(torch.nn.Embedding, CastWeightBiasOp):
def reset_parameters(self):
self.bias = None
return None
def forward_comfy_cast_weights(self, input, out_dtype=None):
output_dtype = out_dtype
if self.weight.dtype == torch.float16 or self.weight.dtype == torch.bfloat16:
out_dtype = None
weight, bias = cast_bias_weight(self, device=input.device, dtype=out_dtype)
return torch.nn.functional.embedding(input, weight, self.padding_idx, self.max_norm, self.norm_type, self.scale_grad_by_freq, self.sparse).to(dtype=output_dtype)
def forward(self, *args, **kwargs):
if self.comfy_cast_weights or len(self.weight_function) > 0 or len(self.bias_function) > 0:
return self.forward_comfy_cast_weights(*args, **kwargs)
else:
if "out_dtype" in kwargs:
kwargs.pop("out_dtype")
return super().forward(*args, **kwargs)
@classmethod
def conv_nd(s, dims, *args, **kwargs):
if dims == 2:
return s.Conv2d(*args, **kwargs)
elif dims == 3:
return s.Conv3d(*args, **kwargs)
else:
raise ValueError(f"unsupported dimensions: {dims}")
class manual_cast(disable_weight_init):
class Linear(disable_weight_init.Linear):
comfy_cast_weights = True
class Conv1d(disable_weight_init.Conv1d):
comfy_cast_weights = True
class Conv2d(disable_weight_init.Conv2d):
comfy_cast_weights = True
class Conv3d(disable_weight_init.Conv3d):
comfy_cast_weights = True
class GroupNorm(disable_weight_init.GroupNorm):
comfy_cast_weights = True
class LayerNorm(disable_weight_init.LayerNorm):
comfy_cast_weights = True
class ConvTranspose2d(disable_weight_init.ConvTranspose2d):
comfy_cast_weights = True
class ConvTranspose1d(disable_weight_init.ConvTranspose1d):
comfy_cast_weights = True
class RMSNorm(disable_weight_init.RMSNorm):
comfy_cast_weights = True
class Embedding(disable_weight_init.Embedding):
comfy_cast_weights = True
def fp8_linear(self, input):
dtype = self.weight.dtype
if dtype not in [torch.float8_e4m3fn]:
return None
tensor_2d = False
if len(input.shape) == 2:
tensor_2d = True
input = input.unsqueeze(1)
input_shape = input.shape
input_dtype = input.dtype
if len(input.shape) == 3:
w, bias = cast_bias_weight(self, input, dtype=dtype, bias_dtype=input_dtype)
w = w.t()
scale_weight = self.scale_weight
scale_input = self.scale_input
if scale_weight is None:
scale_weight = torch.ones((), device=input.device, dtype=torch.float32)
else:
scale_weight = scale_weight.to(input.device)
if scale_input is None:
scale_input = torch.ones((), device=input.device, dtype=torch.float32)
input = torch.clamp(input, min=-448, max=448, out=input)
input = input.reshape(-1, input_shape[2]).to(dtype).contiguous()
else:
scale_input = scale_input.to(input.device)
input = (input * (1.0 / scale_input).to(input_dtype)).reshape(-1, input_shape[2]).to(dtype).contiguous()
if bias is not None:
o = torch._scaled_mm(input, w, out_dtype=input_dtype, bias=bias, scale_a=scale_input, scale_b=scale_weight)
else:
o = torch._scaled_mm(input, w, out_dtype=input_dtype, scale_a=scale_input, scale_b=scale_weight)
if isinstance(o, tuple):
o = o[0]
if tensor_2d:
return o.reshape(input_shape[0], -1)
return o.reshape((-1, input_shape[1], self.weight.shape[0]))
return None
class fp8_ops(manual_cast):
class Linear(manual_cast.Linear):
def reset_parameters(self):
self.scale_weight = None
self.scale_input = None
return None
def forward_comfy_cast_weights(self, input):
if not self.training:
try:
out = fp8_linear(self, input)
if out is not None:
return out
except Exception as e:
logging.info("Exception during fp8 op: {}".format(e))
weight, bias = cast_bias_weight(self, input)
return torch.nn.functional.linear(input, weight, bias)
def scaled_fp8_ops(fp8_matrix_mult=False, scale_input=False, override_dtype=None):
logging.info("Using scaled fp8: fp8 matrix mult: {}, scale input: {}".format(fp8_matrix_mult, scale_input))
class scaled_fp8_op(manual_cast):
class Linear(manual_cast.Linear):
def __init__(self, *args, **kwargs):
if override_dtype is not None:
kwargs['dtype'] = override_dtype
super().__init__(*args, **kwargs)
def reset_parameters(self):
if not hasattr(self, 'scale_weight'):
self.scale_weight = torch.nn.parameter.Parameter(data=torch.ones((), device=self.weight.device, dtype=torch.float32), requires_grad=False)
if not scale_input:
self.scale_input = None
if not hasattr(self, 'scale_input'):
self.scale_input = torch.nn.parameter.Parameter(data=torch.ones((), device=self.weight.device, dtype=torch.float32), requires_grad=False)
return None
def forward_comfy_cast_weights(self, input):
if fp8_matrix_mult:
out = fp8_linear(self, input)
if out is not None:
return out
weight, bias = cast_bias_weight(self, input)
if weight.numel() < input.numel(): #TODO: optimize
return torch.nn.functional.linear(input, weight * self.scale_weight.to(device=weight.device, dtype=weight.dtype), bias)
else:
return torch.nn.functional.linear(input * self.scale_weight.to(device=weight.device, dtype=weight.dtype), weight, bias)
def convert_weight(self, weight, inplace=False, **kwargs):
if inplace:
weight *= self.scale_weight.to(device=weight.device, dtype=weight.dtype)
return weight
else:
return weight * self.scale_weight.to(device=weight.device, dtype=weight.dtype)
def set_weight(self, weight, inplace_update=False, seed=None, **kwargs):
weight = comfy.float.stochastic_rounding(weight / self.scale_weight.to(device=weight.device, dtype=weight.dtype), self.weight.dtype, seed=seed)
if inplace_update:
self.weight.data.copy_(weight)
else:
self.weight = torch.nn.Parameter(weight, requires_grad=False)
return scaled_fp8_op
CUBLAS_IS_AVAILABLE = False
try:
from cublas_ops import CublasLinear
CUBLAS_IS_AVAILABLE = True
except ImportError:
pass
if CUBLAS_IS_AVAILABLE:
class cublas_ops(disable_weight_init):
class Linear(CublasLinear, disable_weight_init.Linear):
def reset_parameters(self):
return None
def forward_comfy_cast_weights(self, input):
return super().forward(input)
def forward(self, *args, **kwargs):
return super().forward(*args, **kwargs)
def pick_operations(weight_dtype, compute_dtype, load_device=None, disable_fast_fp8=False, fp8_optimizations=False, scaled_fp8=None):
fp8_compute = comfy.model_management.supports_fp8_compute(load_device)
if scaled_fp8 is not None:
return scaled_fp8_ops(fp8_matrix_mult=fp8_compute and fp8_optimizations, scale_input=fp8_optimizations, override_dtype=scaled_fp8)
if (
fp8_compute and
(fp8_optimizations or PerformanceFeature.Fp8MatrixMultiplication in args.fast) and
not disable_fast_fp8
):
return fp8_ops
if (
PerformanceFeature.CublasOps in args.fast and
CUBLAS_IS_AVAILABLE and
weight_dtype == torch.float16 and
(compute_dtype == torch.float16 or compute_dtype is None)
):
logging.info("Using cublas ops")
return cublas_ops
if compute_dtype is None or weight_dtype == compute_dtype:
return disable_weight_init
return manual_cast