zerogpu-sdxlTrainer / toolkit /util /comfy_quant_import.py
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"""Import ComfyUI pre-quantized checkpoints onto toolkit modules.
ComfyUI quantized checkpoints mark each quantized submodule with a
``<prefix>.comfy_quant`` uint8 tensor holding a JSON config, alongside the
quantized ``weight`` and its scale tensors. This module walks those markers
and converts the matching submodules in place:
- ``{"format": "int8_tensorwise", "convrot": true, "convrot_groupsize": G}``
per-output-row symmetric int8 on regular-Hadamard-rotated weights — the
exact storage of the toolkit's convrot8 backend
(toolkit/util/convrot_quant.py:ConvRotInt8Quantizer), so the tensors are
attached to its buffers directly (no requantization). Without the
``convrot`` flag the rotation block is 1, i.e. plain per-row int8, which
the same backend also decodes (rotate is the identity at rot_size 1).
- ``{"format": "nvfp4"}`` block-16 fp4 with e4m3 block scales, an fp32
per-tensor scale and an optional AWQ ``pre_quant_scale`` — attached to
the nvfp4 backend (toolkit/util/nvfp4_quant.py).
- an int8 marker on an ``nn.Embedding`` swaps in :class:`Int8Embedding`
(per-row scales, dequantized per lookup).
Linears become OstrisLinear (class swap in place, like
convert_linear_to_ostris), so LoRA attachment, memory management and the
quantized save paths all work unchanged.
"""
import json
from typing import Dict, Tuple
import torch
from toolkit.util.nvfp4_quant import (
Nvfp4Quantizer,
swap_nvfp4_nibbles,
unswizzle_nvfp4_scales,
)
from toolkit.util.ostris_quant import OstrisLinear, get_ostris_quantizer
from toolkit.util.convrot_quant import rotate
def parse_comfy_quant_blob(blob: torch.Tensor) -> dict:
return json.loads(bytes(blob.cpu().tolist()).decode("utf-8"))
class Int8Embedding(torch.nn.Module):
"""An embedding table stored as per-row symmetric int8. Rows are
dequantized per lookup, so the full-precision table never materializes."""
def __init__(self, qweight: torch.Tensor, scales: torch.Tensor, dtype: torch.dtype):
super().__init__()
self.num_embeddings, self.embedding_dim = qweight.shape
self.output_dtype = dtype
self.register_buffer("qweight", qweight.contiguous(), persistent=False)
self.register_buffer(
"scales",
scales.detach().float().reshape(-1).contiguous().view(torch.uint8),
persistent=False,
)
@property
def weight(self):
# full dequantized table, for code that inspects it
scales = self.scales.view(torch.float32)
return (self.qweight.float() * scales.unsqueeze(1)).to(self.output_dtype)
def forward(self, input_ids: torch.Tensor) -> torch.Tensor:
# the table may stay CPU-resident under text-encoder offloading: run
# the (tiny) lookup on the table's device, return on the caller's
flat = input_ids.reshape(-1).to(self.qweight.device)
rows = self.qweight.index_select(0, flat).float()
scales = self.scales.view(torch.float32).index_select(0, flat)
out = (rows * scales.unsqueeze(1)).to(self.output_dtype)
return out.to(input_ids.device).reshape(*input_ids.shape, self.embedding_dim)
class ConvRotInt8Embedding(torch.nn.Module):
"""Per-row int8 embedding whose rows are stored in the ConvRot-rotated basis (the
storage of a comfy convrot int8 linear). Rows are gathered, dequantized and rotated
back per lookup, so neither the full table nor an unrotated copy materializes."""
def __init__(self, qweight: torch.Tensor, scales: torch.Tensor, rot_size: int, dtype: torch.dtype):
super().__init__()
self.num_embeddings, self.embedding_dim = qweight.shape
self.output_dtype = dtype
self.rot_size = int(rot_size)
self.register_buffer("qweight", qweight.contiguous(), persistent=False)
self.register_buffer(
"scales",
scales.detach().float().reshape(-1).contiguous().view(torch.uint8),
persistent=False,
)
@property
def weight(self):
return self.forward(torch.arange(self.num_embeddings, device=self.qweight.device))
def forward(self, input_ids: torch.Tensor) -> torch.Tensor:
flat = input_ids.reshape(-1).to(self.qweight.device)
rows = self.qweight.index_select(0, flat).float()
scales = self.scales.view(torch.float32).index_select(0, flat)
out = rotate(rows * scales.unsqueeze(1), self.rot_size).to(self.output_dtype)
return out.to(input_ids.device).reshape(*input_ids.shape, self.embedding_dim)
@torch.no_grad()
def split_fused_quantized_keys(
state_dict: Dict[str, torch.Tensor],
prefix: str,
dst_prefixes,
) -> Dict[str, torch.Tensor]:
"""Split one fused quantized comfy entry (``<prefix>.weight`` /
``.weight_scale`` / ``.comfy_quant`` / ...) into equal row ranges under
``dst_prefixes`` (out-dim concat order). Exact for every supported format:
int8 rows and their per-row scales slice; fp8's per-tensor scale and
nvfp4's weight_scale_2 / pre_quant_scale are shared by every split; nvfp4
block scales are unswizzled, row-split, and re-swizzled. Mutates and
returns state_dict. Used by classes whose module layout splits a fused
checkpoint projection (e.g. qkv -> to_q/to_k/to_v)."""
from toolkit.util.nvfp4_quant import swizzle_nvfp4_scales
marker = state_dict.pop(f"{prefix}.comfy_quant")
conf = parse_comfy_quant_blob(marker)
fmt = conf.get("format")
weight = state_dict.pop(f"{prefix}.weight")
scale = state_dict.pop(f"{prefix}.weight_scale", None)
pts = state_dict.pop(f"{prefix}.weight_scale_2", None)
pre = state_dict.pop(f"{prefix}.pre_quant_scale", None)
bias = state_dict.pop(f"{prefix}.bias", None)
state_dict.pop(f"{prefix}.input_scale", None)
n = len(dst_prefixes)
if weight.shape[0] % n != 0:
raise ValueError(
f"{prefix}: fused out dim {weight.shape[0]} does not split into {n}"
)
rows = weight.shape[0] // n
scale_parts = None
if scale is not None:
if fmt == "nvfp4":
in_features = weight.shape[1] * 2 # packed fp4 pairs
full = unswizzle_nvfp4_scales(
scale.view(torch.float8_e4m3fn), weight.shape[0], in_features // 16
)
scale_parts = [
swizzle_nvfp4_scales(p).view(torch.float8_e4m3fn)
for p in full.split(rows, dim=0)
]
elif scale.ndim == 0 or scale.numel() == 1:
scale_parts = [scale.clone() for _ in range(n)]
else:
scale_parts = list(scale.reshape(weight.shape[0], -1).split(rows, dim=0))
for i, dst in enumerate(dst_prefixes):
state_dict[f"{dst}.comfy_quant"] = marker.clone()
state_dict[f"{dst}.weight"] = weight[i * rows : (i + 1) * rows].contiguous()
if scale_parts is not None:
state_dict[f"{dst}.weight_scale"] = scale_parts[i].contiguous()
if pts is not None:
state_dict[f"{dst}.weight_scale_2"] = pts.clone()
if pre is not None:
state_dict[f"{dst}.pre_quant_scale"] = pre.clone()
if bias is not None:
state_dict[f"{dst}.bias"] = bias[i * rows : (i + 1) * rows].contiguous()
return state_dict
@torch.no_grad()
def fuse_split_quantized_keys(
state_dict: Dict[str, torch.Tensor],
src_prefixes,
prefix: str,
) -> Dict[str, torch.Tensor]:
"""Inverse of split_fused_quantized_keys: concatenate N split quantized
comfy entries back into one fused entry (out-dim concat in src order).
All parts must share the same format config; fp8 parts must share the same
per-tensor scale (true for entries produced by the splitter). Mutates and
returns state_dict."""
from toolkit.util.nvfp4_quant import swizzle_nvfp4_scales
markers = [state_dict.pop(f"{p}.comfy_quant") for p in src_prefixes]
confs = [parse_comfy_quant_blob(m) for m in markers]
if any(c != confs[0] for c in confs[1:]):
raise ValueError(f"{prefix}: split parts carry different quant configs")
fmt = confs[0].get("format")
weights = [state_dict.pop(f"{p}.weight") for p in src_prefixes]
scales = [state_dict.pop(f"{p}.weight_scale", None) for p in src_prefixes]
ptss = [state_dict.pop(f"{p}.weight_scale_2", None) for p in src_prefixes]
pres = [state_dict.pop(f"{p}.pre_quant_scale", None) for p in src_prefixes]
biases = [state_dict.pop(f"{p}.bias", None) for p in src_prefixes]
state_dict[f"{prefix}.comfy_quant"] = markers[0]
weight = torch.cat(weights, dim=0).contiguous()
state_dict[f"{prefix}.weight"] = weight
if scales[0] is not None:
if fmt == "nvfp4":
in_features = weight.shape[1] * 2
rows = [w.shape[0] for w in weights]
full = torch.cat(
[
unswizzle_nvfp4_scales(
s.view(torch.float8_e4m3fn), r, in_features // 16
)
for s, r in zip(scales, rows)
],
dim=0,
)
state_dict[f"{prefix}.weight_scale"] = swizzle_nvfp4_scales(full).view(
torch.float8_e4m3fn
)
elif scales[0].ndim == 0 or scales[0].numel() == 1:
if any(
not torch.equal(s.reshape(-1), scales[0].reshape(-1)) for s in scales[1:]
):
raise ValueError(
f"{prefix}: per-tensor scales differ across split parts"
)
state_dict[f"{prefix}.weight_scale"] = scales[0]
else:
state_dict[f"{prefix}.weight_scale"] = torch.cat(
[s.reshape(w.shape[0], -1) for s, w in zip(scales, weights)], dim=0
).contiguous()
if ptss[0] is not None:
state_dict[f"{prefix}.weight_scale_2"] = ptss[0]
if pres[0] is not None:
state_dict[f"{prefix}.pre_quant_scale"] = pres[0]
if biases[0] is not None:
state_dict[f"{prefix}.bias"] = torch.cat(biases, dim=0).contiguous()
return state_dict
def _to_ostris(module: torch.nn.Linear, quantizer, orig_dtype: torch.dtype) -> OstrisLinear:
if "weight" in module._parameters:
del module._parameters["weight"]
module.ostris_quantizer = quantizer
module.ostris_orig_dtype = orig_dtype
if module.bias is not None:
module.bias.requires_grad_(False)
module.__class__ = OstrisLinear
return module
@torch.no_grad()
def import_comfy_quantized_layers(
root: torch.nn.Module,
state_dict: Dict[str, torch.Tensor],
orig_dtype: torch.dtype = torch.bfloat16,
key_map=None,
rotated_embedding_rows: bool = False,
) -> Tuple[Dict[str, torch.Tensor], int]:
"""Convert every module a ``comfy_quant`` marker points at and attach its
quantized tensors. Consumes the quantized entries from ``state_dict`` and
returns ``(remaining_state_dict, num_converted)`` — load the remainder
with the regular load_state_dict.
``key_map`` optionally maps a checkpoint prefix to the module path in
``root`` (e.g. comfy text encoder keys onto transformers module paths).
``rotated_embedding_rows`` keeps a convrot int8 embedding table as int8 rows
(:class:`ConvRotInt8Embedding`, rotated back per lookup) instead of
materializing the full dequantized table.
"""
state_dict = dict(state_dict)
converted = 0
marker_keys = [k for k in state_dict.keys() if k.endswith(".comfy_quant")]
for marker_key in marker_keys:
prefix = marker_key[: -len(".comfy_quant")]
conf = parse_comfy_quant_blob(state_dict.pop(marker_key))
fmt = conf.get("format")
module_path = key_map(prefix) if key_map is not None else prefix
module = root.get_submodule(module_path)
weight = state_dict.pop(f"{prefix}.weight")
weight_scale = state_dict.pop(f"{prefix}.weight_scale", None)
if isinstance(module, torch.nn.Embedding):
if fmt != "int8_tensorwise":
raise ValueError(
f"Unsupported comfy quant format {fmt!r} on embedding {prefix}"
)
parent_path, _, attr = module_path.rpartition(".")
parent = root.get_submodule(parent_path) if parent_path else root
if conf.get("convrot") and rotated_embedding_rows:
setattr(
parent,
attr,
ConvRotInt8Embedding(
weight, weight_scale, int(conf.get("convrot_groupsize", 256)), orig_dtype
),
)
elif conf.get("convrot"):
# rows are stored rotated like a linear's weight: attach to a stand-in linear
# (same shape) so the convrot backend undoes the rotation, then keep the table
# as a plain embedding (per-row lookups cannot apply the group rotation)
stand_in = torch.nn.Linear(
module.embedding_dim, module.num_embeddings, bias=False, device="meta"
)
quantizer = get_ostris_quantizer("convrot8")
stand_in.register_buffer("cr8_qdata", weight.contiguous(), persistent=False)
stand_in.register_buffer(
"cr8_scales",
weight_scale.detach().float().reshape(-1).contiguous().view(torch.uint8),
persistent=False,
)
stand_in.cr8_rot_size = int(conf.get("convrot_groupsize", 256))
_to_ostris(stand_in, quantizer, orig_dtype)
table = quantizer.dequantize_folded(stand_in).to(orig_dtype)
new = torch.nn.Embedding(
module.num_embeddings, module.embedding_dim, padding_idx=module.padding_idx,
device="meta", dtype=orig_dtype,
)
new.weight = torch.nn.Parameter(table, requires_grad=False)
setattr(parent, attr, new)
else:
setattr(parent, attr, Int8Embedding(weight, weight_scale, orig_dtype))
converted += 1
continue
if not isinstance(module, torch.nn.Linear):
raise ValueError(
f"comfy_quant marker {prefix} points at {type(module).__name__}, "
"expected nn.Linear or nn.Embedding"
)
if fmt == "float8_e4m3fn":
# fp8_e4m3 weight + fp32 per-tensor scale, dequantized matmul
from toolkit.util.float8_quant import Float8Quantizer
quantizer = get_ostris_quantizer("float8_e4m3fn")
Float8Quantizer.attach_(
module,
weight.view(torch.float8_e4m3fn)
if weight.dtype != torch.float8_e4m3fn
else weight,
weight_scale,
)
elif fmt == "int8_tensorwise":
rot = int(conf.get("convrot_groupsize", 256)) if conf.get("convrot") else 1
quantizer = get_ostris_quantizer("convrot8")
module.register_buffer("cr8_qdata", weight.contiguous(), persistent=False)
module.register_buffer(
"cr8_scales",
weight_scale.detach().float().reshape(-1).contiguous().view(torch.uint8),
persistent=False,
)
module.cr8_rot_size = rot
elif fmt == "nvfp4":
quantizer = get_ostris_quantizer("nvfp4")
# normalize comfy_kitchen's storage to the toolkit's conventions:
# fp4 pairs are packed high-nibble-first and the e4m3 block scales
# are stored in the swizzled cuBLAS 128x4 tile layout
scales = unswizzle_nvfp4_scales(
weight_scale.view(torch.float8_e4m3fn),
module.out_features,
module.in_features // 16,
)
Nvfp4Quantizer.attach_(
module,
packed=swap_nvfp4_nibbles(weight),
scales=scales,
pts=state_dict.pop(f"{prefix}.weight_scale_2"),
pre_scale=state_dict.pop(f"{prefix}.pre_quant_scale", None),
)
elif fmt == "asym_w4a8_int8":
# int4 codebook codes + fp8 group scales + fp32 channel scales on a convrot
# basis: the exact storage of the toolkit's convrotw4a8 backend
from toolkit.util.convrot_w4a8_quant import ConvRotW4A8Quantizer
if f"{prefix}.weight_correction" in state_dict:
raise ValueError(f"asymmetric W4A8 (weight_correction) on {prefix} is not supported")
quantizer = get_ostris_quantizer("convrotw4a8")
ConvRotW4A8Quantizer.attach_(
module,
qdata=weight,
srel=state_dict.pop(f"{prefix}.weight_s_rel"),
s_channel=state_dict.pop(f"{prefix}.weight_s_channel"),
codebook=state_dict.pop(f"{prefix}.weight_codebook", None),
rot_size=int(conf.get("convrot_groupsize", 256)) if conf.get("convrot") else 1,
group_size=int(conf.get("group_size", 16)),
)
else:
raise ValueError(
f"Unsupported comfy quant format {fmt!r} on {prefix} "
"(supported: int8_tensorwise, nvfp4, float8_e4m3fn, asym_w4a8_int8)"
)
# drop unused calibration extras if present
state_dict.pop(f"{prefix}.input_scale", None)
_to_ostris(module, quantizer, orig_dtype)
bias = state_dict.pop(f"{prefix}.bias", None)
if bias is not None and module.bias is not None:
# bias may still be a meta parameter when the model was built under
# a meta device context
module._parameters["bias"] = torch.nn.Parameter(
bias.detach().clone(), requires_grad=False
)
converted += 1
# legacy ComfyUI scaled-fp8 checkpoints (e.g. the wan *_fp8_scaled files):
# a top-level ``scaled_fp8`` marker tensor plus per-layer fp8 ``weight``
# and scalar fp32 ``scale_weight`` — the float8 backend's exact storage.
# ``scale_input`` (activation quant) is dropped; matmuls run dequantized.
if "scaled_fp8" in state_dict:
from toolkit.util.float8_quant import Float8Quantizer
state_dict.pop("scaled_fp8")
for scale_key in [k for k in state_dict if k.endswith(".scale_weight")]:
prefix = scale_key[: -len(".scale_weight")]
module_path = key_map(prefix) if key_map is not None else prefix
module = root.get_submodule(module_path)
if not isinstance(module, torch.nn.Linear):
raise ValueError(
f"scaled_fp8 entry {prefix} points at {type(module).__name__}, "
"expected nn.Linear"
)
weight = state_dict.pop(f"{prefix}.weight")
scale = state_dict.pop(scale_key)
state_dict.pop(f"{prefix}.scale_input", None)
quantizer = get_ostris_quantizer("float8_e4m3fn")
Float8Quantizer.attach_(
module,
weight
if weight.dtype == torch.float8_e4m3fn
else weight.view(torch.float8_e4m3fn),
scale,
)
_to_ostris(module, quantizer, orig_dtype)
bias = state_dict.pop(f"{prefix}.bias", None)
if bias is not None and module.bias is not None:
module._parameters["bias"] = torch.nn.Parameter(
bias.detach().clone(), requires_grad=False
)
converted += 1
return state_dict, converted