ComfyUI/comfy/quant_ops.py
comfyanonymous e1e50e017c Make old scaled fp8 format use the new mixed quant ops system.
Since model saving is not implemented for the mixed quant system this
breaks model saving for every scaled fp8 model which needs to be fixed
before this gets merged.
2025-11-30 00:33:01 -05:00

577 lines
20 KiB
Python

import torch
import logging
from typing import Tuple, Dict
import comfy.float
_LAYOUT_REGISTRY = {}
_GENERIC_UTILS = {}
def register_layout_op(torch_op, layout_type):
"""
Decorator to register a layout-specific operation handler.
Args:
torch_op: PyTorch operation (e.g., torch.ops.aten.linear.default)
layout_type: Layout class (e.g., TensorCoreFP8Layout)
Example:
@register_layout_op(torch.ops.aten.linear.default, TensorCoreFP8Layout)
def fp8_linear(func, args, kwargs):
# FP8-specific linear implementation
...
"""
def decorator(handler_func):
if torch_op not in _LAYOUT_REGISTRY:
_LAYOUT_REGISTRY[torch_op] = {}
_LAYOUT_REGISTRY[torch_op][layout_type] = handler_func
return handler_func
return decorator
def register_generic_util(torch_op):
"""
Decorator to register a generic utility that works for all layouts.
Args:
torch_op: PyTorch operation (e.g., torch.ops.aten.detach.default)
Example:
@register_generic_util(torch.ops.aten.detach.default)
def generic_detach(func, args, kwargs):
# Works for any layout
...
"""
def decorator(handler_func):
_GENERIC_UTILS[torch_op] = handler_func
return handler_func
return decorator
def _get_layout_from_args(args):
for arg in args:
if isinstance(arg, QuantizedTensor):
return arg._layout_type
elif isinstance(arg, (list, tuple)):
for item in arg:
if isinstance(item, QuantizedTensor):
return item._layout_type
return None
def _move_layout_params_to_device(params, device):
new_params = {}
for k, v in params.items():
if isinstance(v, torch.Tensor):
new_params[k] = v.to(device=device)
else:
new_params[k] = v
return new_params
def _copy_layout_params(params):
new_params = {}
for k, v in params.items():
if isinstance(v, torch.Tensor):
new_params[k] = v.clone()
else:
new_params[k] = v
return new_params
def _copy_layout_params_inplace(src, dst, non_blocking=False):
for k, v in src.items():
if isinstance(v, torch.Tensor):
dst[k].copy_(v, non_blocking=non_blocking)
else:
dst[k] = v
class QuantizedLayout:
"""
Base class for quantization layouts.
A layout encapsulates the format-specific logic for quantization/dequantization
and provides a uniform interface for extracting raw tensors needed for computation.
New quantization formats should subclass this and implement the required methods.
"""
@classmethod
def quantize(cls, tensor, **kwargs) -> Tuple[torch.Tensor, Dict]:
raise NotImplementedError(f"{cls.__name__} must implement quantize()")
@staticmethod
def dequantize(qdata, **layout_params) -> torch.Tensor:
raise NotImplementedError("TensorLayout must implement dequantize()")
@classmethod
def get_plain_tensors(cls, qtensor) -> torch.Tensor:
raise NotImplementedError(f"{cls.__name__} must implement get_plain_tensors()")
class QuantizedTensor(torch.Tensor):
"""
Universal quantized tensor that works with any layout.
This tensor subclass uses a pluggable layout system to support multiple
quantization formats (FP8, INT4, INT8, etc.) without code duplication.
The layout_type determines format-specific behavior, while common operations
(detach, clone, to) are handled generically.
Attributes:
_qdata: The quantized tensor data
_layout_type: Layout class (e.g., TensorCoreFP8Layout)
_layout_params: Dict with layout-specific params (scale, zero_point, etc.)
"""
@staticmethod
def __new__(cls, qdata, layout_type, layout_params):
"""
Create a quantized tensor.
Args:
qdata: The quantized data tensor
layout_type: Layout class (subclass of QuantizedLayout)
layout_params: Dict with layout-specific parameters
"""
return torch.Tensor._make_wrapper_subclass(cls, qdata.shape, device=qdata.device, dtype=qdata.dtype, requires_grad=False)
def __init__(self, qdata, layout_type, layout_params):
self._qdata = qdata
self._layout_type = layout_type
self._layout_params = layout_params
def __repr__(self):
layout_name = self._layout_type
param_str = ", ".join(f"{k}={v}" for k, v in list(self._layout_params.items())[:2])
return f"QuantizedTensor(shape={self.shape}, layout={layout_name}, {param_str})"
@property
def layout_type(self):
return self._layout_type
def __tensor_flatten__(self):
"""
Tensor flattening protocol for proper device movement.
"""
inner_tensors = ["_qdata"]
ctx = {
"layout_type": self._layout_type,
}
tensor_params = {}
non_tensor_params = {}
for k, v in self._layout_params.items():
if isinstance(v, torch.Tensor):
tensor_params[k] = v
else:
non_tensor_params[k] = v
ctx["tensor_param_keys"] = list(tensor_params.keys())
ctx["non_tensor_params"] = non_tensor_params
for k, v in tensor_params.items():
attr_name = f"_layout_param_{k}"
object.__setattr__(self, attr_name, v)
inner_tensors.append(attr_name)
return inner_tensors, ctx
@staticmethod
def __tensor_unflatten__(inner_tensors, ctx, outer_size, outer_stride):
"""
Tensor unflattening protocol for proper device movement.
Reconstructs the QuantizedTensor after device movement.
"""
layout_type = ctx["layout_type"]
layout_params = dict(ctx["non_tensor_params"])
for key in ctx["tensor_param_keys"]:
attr_name = f"_layout_param_{key}"
layout_params[key] = inner_tensors[attr_name]
return QuantizedTensor(inner_tensors["_qdata"], layout_type, layout_params)
@classmethod
def from_float(cls, tensor, layout_type, **quantize_kwargs) -> 'QuantizedTensor':
qdata, layout_params = LAYOUTS[layout_type].quantize(tensor, **quantize_kwargs)
return cls(qdata, layout_type, layout_params)
def dequantize(self) -> torch.Tensor:
return LAYOUTS[self._layout_type].dequantize(self._qdata, **self._layout_params)
@classmethod
def __torch_dispatch__(cls, func, types, args=(), kwargs=None):
kwargs = kwargs or {}
# Step 1: Check generic utilities first (detach, clone, to, etc.)
if func in _GENERIC_UTILS:
return _GENERIC_UTILS[func](func, args, kwargs)
# Step 2: Check layout-specific handlers (linear, matmul, etc.)
layout_type = _get_layout_from_args(args)
if layout_type and func in _LAYOUT_REGISTRY:
handler = _LAYOUT_REGISTRY[func].get(layout_type)
if handler:
return handler(func, args, kwargs)
# Step 3: Fallback to dequantization
if isinstance(args[0] if args else None, QuantizedTensor):
logging.info(f"QuantizedTensor: Unhandled operation {func}, falling back to dequantization. kwargs={kwargs}")
return cls._dequant_and_fallback(func, args, kwargs)
@classmethod
def _dequant_and_fallback(cls, func, args, kwargs):
def dequant_arg(arg):
if isinstance(arg, QuantizedTensor):
return arg.dequantize()
elif isinstance(arg, (list, tuple)):
return type(arg)(dequant_arg(a) for a in arg)
return arg
new_args = dequant_arg(args)
new_kwargs = dequant_arg(kwargs)
return func(*new_args, **new_kwargs)
def data_ptr(self):
return self._qdata.data_ptr()
def is_pinned(self):
return self._qdata.is_pinned()
def is_contiguous(self, *arg, **kwargs):
return self._qdata.is_contiguous(*arg, **kwargs)
# ==============================================================================
# Generic Utilities (Layout-Agnostic Operations)
# ==============================================================================
def _create_transformed_qtensor(qt, transform_fn):
new_data = transform_fn(qt._qdata)
new_params = _copy_layout_params(qt._layout_params)
return QuantizedTensor(new_data, qt._layout_type, new_params)
def _handle_device_transfer(qt, target_device, target_dtype=None, target_layout=None, op_name="to"):
if target_dtype is not None and target_dtype != qt.dtype:
logging.warning(
f"QuantizedTensor: dtype conversion requested to {target_dtype}, "
f"but not supported for quantized tensors. Ignoring dtype."
)
if target_layout is not None and target_layout != torch.strided:
logging.warning(
f"QuantizedTensor: layout change requested to {target_layout}, "
f"but not supported. Ignoring layout."
)
# Handle device transfer
current_device = qt._qdata.device
if target_device is not None:
# Normalize device for comparison
if isinstance(target_device, str):
target_device = torch.device(target_device)
if isinstance(current_device, str):
current_device = torch.device(current_device)
if target_device != current_device:
logging.debug(f"QuantizedTensor.{op_name}: Moving from {current_device} to {target_device}")
new_q_data = qt._qdata.to(device=target_device)
new_params = _move_layout_params_to_device(qt._layout_params, target_device)
new_qt = QuantizedTensor(new_q_data, qt._layout_type, new_params)
logging.debug(f"QuantizedTensor.{op_name}: Created new tensor on {target_device}")
return new_qt
logging.debug(f"QuantizedTensor.{op_name}: No device change needed, returning original")
return qt
@register_generic_util(torch.ops.aten.detach.default)
def generic_detach(func, args, kwargs):
"""Detach operation - creates a detached copy of the quantized tensor."""
qt = args[0]
if isinstance(qt, QuantizedTensor):
return _create_transformed_qtensor(qt, lambda x: x.detach())
return func(*args, **kwargs)
@register_generic_util(torch.ops.aten.clone.default)
def generic_clone(func, args, kwargs):
"""Clone operation - creates a deep copy of the quantized tensor."""
qt = args[0]
if isinstance(qt, QuantizedTensor):
return _create_transformed_qtensor(qt, lambda x: x.clone())
return func(*args, **kwargs)
@register_generic_util(torch.ops.aten._to_copy.default)
def generic_to_copy(func, args, kwargs):
"""Device/dtype transfer operation - handles .to(device) calls."""
qt = args[0]
if isinstance(qt, QuantizedTensor):
return _handle_device_transfer(
qt,
target_device=kwargs.get('device', None),
target_dtype=kwargs.get('dtype', None),
op_name="_to_copy"
)
return func(*args, **kwargs)
@register_generic_util(torch.ops.aten.to.dtype_layout)
def generic_to_dtype_layout(func, args, kwargs):
"""Handle .to(device) calls using the dtype_layout variant."""
qt = args[0]
if isinstance(qt, QuantizedTensor):
return _handle_device_transfer(
qt,
target_device=kwargs.get('device', None),
target_dtype=kwargs.get('dtype', None),
target_layout=kwargs.get('layout', None),
op_name="to"
)
return func(*args, **kwargs)
@register_generic_util(torch.ops.aten.copy_.default)
def generic_copy_(func, args, kwargs):
qt_dest = args[0]
src = args[1]
non_blocking = args[2] if len(args) > 2 else False
if isinstance(qt_dest, QuantizedTensor):
if isinstance(src, QuantizedTensor):
# Copy from another quantized tensor
qt_dest._qdata.copy_(src._qdata, non_blocking=non_blocking)
qt_dest._layout_type = src._layout_type
_copy_layout_params_inplace(src._layout_params, qt_dest._layout_params, non_blocking=non_blocking)
else:
# Copy from regular tensor - just copy raw data
qt_dest._qdata.copy_(src)
return qt_dest
return func(*args, **kwargs)
@register_generic_util(torch.ops.aten.to.dtype)
def generic_to_dtype(func, args, kwargs):
"""Handle .to(dtype) calls - dtype conversion only."""
src = args[0]
if isinstance(src, QuantizedTensor):
# For dtype-only conversion, just change the orig_dtype, no real cast is needed
target_dtype = args[1] if len(args) > 1 else kwargs.get('dtype')
src._layout_params["orig_dtype"] = target_dtype
return src
return func(*args, **kwargs)
@register_generic_util(torch.ops.aten._has_compatible_shallow_copy_type.default)
def generic_has_compatible_shallow_copy_type(func, args, kwargs):
return True
@register_generic_util(torch.ops.aten.empty_like.default)
def generic_empty_like(func, args, kwargs):
"""Empty_like operation - creates an empty tensor with the same quantized structure."""
qt = args[0]
if isinstance(qt, QuantizedTensor):
# Create empty tensor with same shape and dtype as the quantized data
hp_dtype = kwargs.pop('dtype', qt._layout_params["orig_dtype"])
new_qdata = torch.empty_like(qt._qdata, **kwargs)
# Handle device transfer for layout params
target_device = kwargs.get('device', new_qdata.device)
new_params = _move_layout_params_to_device(qt._layout_params, target_device)
# Update orig_dtype if dtype is specified
new_params['orig_dtype'] = hp_dtype
return QuantizedTensor(new_qdata, qt._layout_type, new_params)
return func(*args, **kwargs)
# ==============================================================================
# FP8 Layout + Operation Handlers
# ==============================================================================
class TensorCoreFP8Layout(QuantizedLayout):
"""
Storage format:
- qdata: FP8 tensor (torch.float8_e4m3fn or torch.float8_e5m2)
- scale: Scalar tensor (float32) for dequantization
- orig_dtype: Original dtype before quantization (for casting back)
"""
@classmethod
def quantize(cls, tensor, scale=None, dtype=torch.float8_e4m3fn, stochastic_rounding=0, inplace_ops=False):
orig_dtype = tensor.dtype
if scale == "recalculate":
scale = torch.amax(tensor.abs()) / torch.finfo(dtype).max
if scale is not None:
if not isinstance(scale, torch.Tensor):
scale = torch.tensor(scale)
scale = scale.to(device=tensor.device, dtype=torch.float32)
if inplace_ops:
tensor *= (1.0 / scale).to(tensor.dtype)
else:
tensor = tensor * (1.0 / scale).to(tensor.dtype)
else:
scale = torch.ones((), device=tensor.device, dtype=torch.float32)
if stochastic_rounding > 0:
tensor = comfy.float.stochastic_rounding(tensor, dtype=dtype, seed=stochastic_rounding)
else:
lp_amax = torch.finfo(dtype).max
torch.clamp(tensor, min=-lp_amax, max=lp_amax, out=tensor)
tensor = tensor.to(dtype, memory_format=torch.contiguous_format)
layout_params = {
'scale': scale,
'orig_dtype': orig_dtype
}
return tensor, layout_params
@staticmethod
def dequantize(qdata, scale, orig_dtype, **kwargs):
plain_tensor = torch.ops.aten._to_copy.default(qdata, dtype=orig_dtype)
plain_tensor.mul_(scale)
return plain_tensor
@classmethod
def get_plain_tensors(cls, qtensor):
return qtensor._qdata, qtensor._layout_params['scale']
QUANT_ALGOS = {
"float8_e4m3fn": {
"storage_t": torch.float8_e4m3fn,
"parameters": {"weight_scale", "input_scale"},
"comfy_tensor_layout": "TensorCoreFP8Layout",
},
}
LAYOUTS = {
"TensorCoreFP8Layout": TensorCoreFP8Layout,
}
@register_layout_op(torch.ops.aten.linear.default, "TensorCoreFP8Layout")
def fp8_linear(func, args, kwargs):
input_tensor = args[0]
weight = args[1]
bias = args[2] if len(args) > 2 else None
if isinstance(input_tensor, QuantizedTensor) and isinstance(weight, QuantizedTensor):
plain_input, scale_a = TensorCoreFP8Layout.get_plain_tensors(input_tensor)
plain_weight, scale_b = TensorCoreFP8Layout.get_plain_tensors(weight)
out_dtype = kwargs.get("out_dtype")
if out_dtype is None:
out_dtype = input_tensor._layout_params['orig_dtype']
weight_t = plain_weight.t()
tensor_2d = False
if len(plain_input.shape) == 2:
tensor_2d = True
plain_input = plain_input.unsqueeze(1)
input_shape = plain_input.shape
if len(input_shape) != 3:
return None
try:
output = torch._scaled_mm(
plain_input.reshape(-1, input_shape[2]).contiguous(),
weight_t,
bias=bias,
scale_a=scale_a,
scale_b=scale_b,
out_dtype=out_dtype,
)
if isinstance(output, tuple): # TODO: remove when we drop support for torch 2.4
output = output[0]
if not tensor_2d:
output = output.reshape((-1, input_shape[1], weight.shape[0]))
if output.dtype in [torch.float8_e4m3fn, torch.float8_e5m2]:
output_scale = scale_a * scale_b
output_params = {
'scale': output_scale,
'orig_dtype': input_tensor._layout_params['orig_dtype']
}
return QuantizedTensor(output, "TensorCoreFP8Layout", output_params)
else:
return output
except Exception as e:
raise RuntimeError(f"FP8 _scaled_mm failed, falling back to dequantization: {e}")
# Case 2: DQ Fallback
if isinstance(weight, QuantizedTensor):
weight = weight.dequantize()
if isinstance(input_tensor, QuantizedTensor):
input_tensor = input_tensor.dequantize()
return torch.nn.functional.linear(input_tensor, weight, bias)
def fp8_mm_(input_tensor, weight, bias=None, out_dtype=None):
if out_dtype is None:
out_dtype = input_tensor._layout_params['orig_dtype']
plain_input, scale_a = TensorCoreFP8Layout.get_plain_tensors(input_tensor)
plain_weight, scale_b = TensorCoreFP8Layout.get_plain_tensors(weight)
output = torch._scaled_mm(
plain_input.contiguous(),
plain_weight,
bias=bias,
scale_a=scale_a,
scale_b=scale_b,
out_dtype=out_dtype,
)
if isinstance(output, tuple): # TODO: remove when we drop support for torch 2.4
output = output[0]
return output
@register_layout_op(torch.ops.aten.addmm.default, "TensorCoreFP8Layout")
def fp8_addmm(func, args, kwargs):
input_tensor = args[1]
weight = args[2]
bias = args[0]
if isinstance(input_tensor, QuantizedTensor) and isinstance(weight, QuantizedTensor):
return fp8_mm_(input_tensor, weight, bias=bias, out_dtype=kwargs.get("out_dtype", None))
a = list(args)
if isinstance(args[0], QuantizedTensor):
a[0] = args[0].dequantize()
if isinstance(args[1], QuantizedTensor):
a[1] = args[1].dequantize()
if isinstance(args[2], QuantizedTensor):
a[2] = args[2].dequantize()
return func(*a, **kwargs)
@register_layout_op(torch.ops.aten.mm.default, "TensorCoreFP8Layout")
def fp8_mm(func, args, kwargs):
input_tensor = args[0]
weight = args[1]
if isinstance(input_tensor, QuantizedTensor) and isinstance(weight, QuantizedTensor):
return fp8_mm_(input_tensor, weight, bias=None, out_dtype=kwargs.get("out_dtype", None))
a = list(args)
if isinstance(args[0], QuantizedTensor):
a[0] = args[0].dequantize()
if isinstance(args[1], QuantizedTensor):
a[1] = args[1].dequantize()
return func(*a, **kwargs)
@register_layout_op(torch.ops.aten.view.default, "TensorCoreFP8Layout")
@register_layout_op(torch.ops.aten.t.default, "TensorCoreFP8Layout")
def fp8_func(func, args, kwargs):
input_tensor = args[0]
if isinstance(input_tensor, QuantizedTensor):
plain_input, scale_a = TensorCoreFP8Layout.get_plain_tensors(input_tensor)
ar = list(args)
ar[0] = plain_input
return QuantizedTensor(func(*ar, **kwargs), "TensorCoreFP8Layout", input_tensor._layout_params)
return func(*args, **kwargs)