model.py

# Copyright 2024-2025 The Alibaba Wan Team Authors. All rights reserved.
# 1. 标准库导入
import gc
import math
import os
import sys
from pathlib import Path

# 2. 第三方库导入
import torch
import torch.nn as nn
import torch.nn.functional as F
from loguru import logger

current_dir = Path(__file__).resolve().parent
project_root = current_dir.parent.parent.parent.parent.parent.parent
if str(project_root) not in sys.path:
    sys.path.insert(0, str(project_root))

from lightx2v.common.modules.weight_module import WeightModule, WeightModuleList  # noqa E402
from lightx2v.common.offload.manager import WeightAsyncStreamManager  # noqa E402
from lightx2v.common.ops import *  # noqa E402
from lightx2v.models.input_encoders.hf.q_linear import (  # noqa E402
    Q8FQuantLinearFp8,  # noqa E402
    Q8FQuantLinearInt8,  # noqa E402
    SglQuantLinearFp8,  # noqa E402
    TorchaoQuantLinearInt8,  # noqa E402
    VllmQuantLinearInt8,  # noqa E402
)
from lightx2v.models.input_encoders.hf.wan.t5.tokenizer import HuggingfaceTokenizer  # noqa E402
from lightx2v.utils.envs import *  # noqa E402
from lightx2v.utils.registry_factory import (  # noqa E402
    EMBEDDING_WEIGHT_REGISTER,  # noqa E402
    MM_WEIGHT_REGISTER,  # noqa E402
    RMS_WEIGHT_REGISTER,  # noqa E402
)
from lightx2v.utils.utils import load_weights  # noqa E402

__all__ = [
    "T5Model",
    "T5Encoder",
    "T5Decoder",
    "T5EncoderModel",
]


class T5OffloadBlocksWeights(WeightModule):
    def __init__(self, block_nums, mm_type):
        super().__init__()
        self.block_nums = block_nums
        self.blocks = WeightModuleList([T5OffloadSelfAttention(i, mm_type) for i in range(block_nums)])
        self.add_module("blocks", self.blocks)


class T5OffloadSelfAttention(WeightModule):
    def __init__(self, block_index, mm_type, block_prefix="blocks"):
        super().__init__()
        self.block_index = block_index
        if mm_type is None:
            mm_type = "Default"
        self.mm_type = mm_type

        self.add_module(
            "norm1",
            RMS_WEIGHT_REGISTER["sgl-kernel"](
                f"{block_prefix}.{self.block_index}.norm1.weight",
            ),
        )
        self.add_module(
            "norm2",
            RMS_WEIGHT_REGISTER["sgl-kernel"](
                f"{block_prefix}.{self.block_index}.norm2.weight",
            ),
        )
        self.add_module(
            "pos_embedding",
            EMBEDDING_WEIGHT_REGISTER["Default"](
                f"{block_prefix}.{self.block_index}.pos_embedding.embedding.weight",
            ),
        )

        self.compute_phases = WeightModuleList(
            [
                T5OffloadAttention(
                    block_index,
                    block_prefix,
                    mm_type,
                ),
                T5OffloadFeedForward(
                    block_index,
                    block_prefix,
                    mm_type,
                ),
            ]
        )
        self.add_module("compute_phases", self.compute_phases)


class T5OffloadAttention(WeightModule):
    def __init__(self, block_index, block_prefix, mm_type):
        super().__init__()
        self.block_index = block_index
        self.mm_type = mm_type

        self.add_module(
            "attn_q",
            MM_WEIGHT_REGISTER[self.mm_type](f"{block_prefix}.{self.block_index}.attn.q.weight", None),
        )
        self.add_module(
            "attn_k",
            MM_WEIGHT_REGISTER[self.mm_type](f"{block_prefix}.{self.block_index}.attn.k.weight", None),
        )
        self.add_module(
            "attn_v",
            MM_WEIGHT_REGISTER[self.mm_type](f"{block_prefix}.{self.block_index}.attn.v.weight", None),
        )
        self.add_module(
            "attn_o",
            MM_WEIGHT_REGISTER[self.mm_type](f"{block_prefix}.{self.block_index}.attn.o.weight", None),
        )


class T5OffloadFeedForward(WeightModule):
    def __init__(self, block_index, block_prefix, mm_type):
        super().__init__()
        self.block_index = block_index
        self.mm_type = mm_type

        self.add_module(
            "ffn_fc1",
            MM_WEIGHT_REGISTER[self.mm_type](f"{block_prefix}.{self.block_index}.ffn.fc1.weight", None),
        )
        self.add_module(
            "ffn_fc2",
            MM_WEIGHT_REGISTER[self.mm_type](f"{block_prefix}.{self.block_index}.ffn.fc2.weight", None),
        )
        self.add_module(
            "ffn_gate_0",
            MM_WEIGHT_REGISTER[self.mm_type](f"{block_prefix}.{self.block_index}.ffn.gate.0.weight", None),
        )
        self.gelu = GELU()


def fp16_clamp(x):
    if x.dtype == torch.float16 and torch.isinf(x).any():
        clamp = torch.finfo(x.dtype).max - 1000
        x = torch.clamp(x, min=-clamp, max=clamp)
    return x


def init_weights(m):
    if isinstance(m, T5LayerNorm):
        nn.init.ones_(m.weight)
    elif isinstance(m, T5Model):
        nn.init.normal_(m.token_embedding.weight, std=1.0)
    elif isinstance(m, T5FeedForward):
        nn.init.normal_(m.gate[0].weight, std=m.dim**-0.5)
        nn.init.normal_(m.fc1.weight, std=m.dim**-0.5)
        nn.init.normal_(m.fc2.weight, std=m.dim_ffn**-0.5)
    elif isinstance(m, T5Attention):
        nn.init.normal_(m.q.weight, std=(m.dim * m.dim_attn) ** -0.5)
        nn.init.normal_(m.k.weight, std=m.dim**-0.5)
        nn.init.normal_(m.v.weight, std=m.dim**-0.5)
        nn.init.normal_(m.o.weight, std=(m.num_heads * m.dim_attn) ** -0.5)
    elif isinstance(m, T5RelativeEmbedding):
        nn.init.normal_(m.embedding.weight, std=(2 * m.num_buckets * m.num_heads) ** -0.5)


class GELU(nn.Module):
    def forward(self, x):
        return 0.5 * x * (1.0 + torch.tanh(math.sqrt(2.0 / math.pi) * (x + 0.044715 * torch.pow(x, 3.0))))


class T5LayerNorm(nn.Module):
    def __init__(self, dim, eps=1e-6, dtype=torch.float16):
        super(T5LayerNorm, self).__init__()
        self.dim = dim
        self.eps = eps
        self.weight = nn.Parameter(torch.ones(dim, dtype=dtype))

    def forward(self, x):
        x = x * torch.rsqrt(x.float().pow(2).mean(dim=-1, keepdim=True) + self.eps)
        if self.weight.dtype in [torch.float16, torch.bfloat16]:
            x = x.type_as(self.weight)
        return self.weight * x


class T5Attention(nn.Module):
    def __init__(
        self,
        dim,
        dim_attn,
        num_heads,
        dropout=0.1,
        quantized=False,
        quant_scheme=None,
        dtype=torch.bfloat16,
    ):
        assert dim_attn % num_heads == 0
        super(T5Attention, self).__init__()
        self.dim = dim
        self.dim_attn = dim_attn
        self.num_heads = num_heads
        self.head_dim = dim_attn // num_heads

        if quantized:
            if quant_scheme in ["int8", "int8-vllm"]:
                linear_cls = VllmQuantLinearInt8
            elif quant_scheme in ["fp8", "fp8-sgl"]:
                linear_cls = SglQuantLinearFp8
            elif quant_scheme == "int8-torchao":
                linear_cls = TorchaoQuantLinearInt8
            elif quant_scheme == "int8-q8f":
                linear_cls = Q8FQuantLinearInt8
            elif quant_scheme == "fp8-q8f":
                linear_cls = Q8FQuantLinearFp8
            else:
                NotImplementedError(f"Unsupported T5 quant scheme: {quant_scheme}")
        else:
            linear_cls = nn.Linear

        # layers
        self.q = linear_cls(dim, dim_attn, bias=False, dtype=dtype)
        self.k = linear_cls(dim, dim_attn, bias=False, dtype=dtype)
        self.v = linear_cls(dim, dim_attn, bias=False, dtype=dtype)
        self.o = linear_cls(dim_attn, dim, bias=False, dtype=dtype)
        self.dropout = nn.Dropout(dropout)

    def forward(self, x, context=None, mask=None, pos_bias=None):
        """
        x:          [B, L1, C].
        context:    [B, L2, C] or None.
        mask:       [B, L2] or [B, L1, L2] or None.
        """
        # check inputs
        context = x if context is None else context
        b, n, c = x.size(0), self.num_heads, self.head_dim

        # compute query, key, value
        q = self.q(x).view(b, -1, n, c)
        k = self.k(context).view(b, -1, n, c)
        v = self.v(context).view(b, -1, n, c)

        # attention bias
        attn_bias = x.new_zeros(b, n, q.size(1), k.size(1))
        if pos_bias is not None:
            attn_bias += pos_bias
        if mask is not None:
            assert mask.ndim in [2, 3]
            mask = mask.view(b, 1, 1, -1) if mask.ndim == 2 else mask.unsqueeze(1)
            attn_bias.masked_fill_(mask == 0, torch.finfo(x.dtype).min)

        # compute attention (T5 does not use scaling)
        attn = torch.einsum("binc,bjnc->bnij", q, k) + attn_bias
        attn = F.softmax(attn.float(), dim=-1).type_as(attn)
        x = torch.einsum("bnij,bjnc->binc", attn, v)
        x = x.reshape(b, -1, n * c)
        x = self.o(x)

        return x


class T5FeedForward(nn.Module):
    def __init__(
        self,
        dim,
        dim_ffn,
        dropout=0.1,
        quantized=False,
        quant_scheme=None,
        dtype=torch.bfloat16,
    ):
        super(T5FeedForward, self).__init__()
        self.dim = dim
        self.dim_ffn = dim_ffn

        if quantized:
            if quant_scheme in ["int8", "int8-vllm"]:
                linear_cls = VllmQuantLinearInt8
            elif quant_scheme in ["fp8", "fp8-sgl"]:
                linear_cls = SglQuantLinearFp8
            elif quant_scheme == "int8-torchao":
                linear_cls = TorchaoQuantLinearInt8
            elif quant_scheme == "int8-q8f":
                linear_cls = Q8FQuantLinearInt8
            elif quant_scheme == "fp8-q8f":
                linear_cls = Q8FQuantLinearFp8
            else:
                NotImplementedError(f"Unsupported T5 quant scheme: {quant_scheme}")
        else:
            linear_cls = nn.Linear
        # layers
        self.gate = nn.Sequential(linear_cls(dim, dim_ffn, bias=False, dtype=dtype), GELU())

        self.fc1 = linear_cls(dim, dim_ffn, bias=False, dtype=dtype)
        self.fc2 = linear_cls(dim_ffn, dim, bias=False, dtype=dtype)
        self.dropout = nn.Dropout(dropout)

    def forward(self, x):
        x = self.fc1(x) * self.gate(x)
        x = self.dropout(x)
        x = self.fc2(x)
        x = self.dropout(x)
        return x


class T5SelfAttention(nn.Module):
    def __init__(
        self,
        dim,
        dim_attn,
        dim_ffn,
        num_heads,
        num_buckets,
        shared_pos=True,
        dropout=0.1,
        quantized=False,
        quant_scheme=None,
        dtype=torch.bfloat16,
    ):
        super(T5SelfAttention, self).__init__()
        self.dim = dim
        self.dim_attn = dim_attn
        self.dim_ffn = dim_ffn
        self.num_heads = num_heads
        self.num_buckets = num_buckets
        self.shared_pos = shared_pos

        # layers
        self.norm1 = T5LayerNorm(dim, dtype=dtype)
        self.attn = T5Attention(dim, dim_attn, num_heads, dropout, quantized, quant_scheme, dtype)
        self.norm2 = T5LayerNorm(dim, dtype=dtype)
        self.ffn = T5FeedForward(dim, dim_ffn, dropout, quantized, quant_scheme, dtype=dtype)
        self.pos_embedding = None if shared_pos else T5RelativeEmbedding(num_buckets, num_heads, bidirectional=True, dtype=dtype)

    def forward(self, x, mask=None, pos_bias=None):
        e = pos_bias if self.shared_pos else self.pos_embedding(x.size(1), x.size(1))
        x = fp16_clamp(x + self.attn(self.norm1(x), mask=mask, pos_bias=e))
        x = fp16_clamp(x + self.ffn(self.norm2(x)))

        return x


class T5CrossAttention(nn.Module):
    def __init__(
        self,
        dim,
        dim_attn,
        dim_ffn,
        num_heads,
        num_buckets,
        shared_pos=True,
        dropout=0.1,
    ):
        super(T5CrossAttention, self).__init__()
        self.dim = dim
        self.dim_attn = dim_attn
        self.dim_ffn = dim_ffn
        self.num_heads = num_heads
        self.num_buckets = num_buckets
        self.shared_pos = shared_pos

        # layers
        self.norm1 = T5LayerNorm(dim)
        self.self_attn = T5Attention(dim, dim_attn, num_heads, dropout)
        self.norm2 = T5LayerNorm(dim)
        self.cross_attn = T5Attention(dim, dim_attn, num_heads, dropout)
        self.norm3 = T5LayerNorm(dim)
        self.ffn = T5FeedForward(dim, dim_ffn, dropout)
        self.pos_embedding = None if shared_pos else T5RelativeEmbedding(num_buckets, num_heads, bidirectional=False)

    def forward(self, x, mask=None, encoder_states=None, encoder_mask=None, pos_bias=None):
        e = pos_bias if self.shared_pos else self.pos_embedding(x.size(1), x.size(1))
        x = fp16_clamp(x + self.self_attn(self.norm1(x), mask=mask, pos_bias=e))
        x = fp16_clamp(x + self.cross_attn(self.norm2(x), context=encoder_states, mask=encoder_mask))
        x = fp16_clamp(x + self.ffn(self.norm3(x)))
        return x


class T5RelativeEmbedding(nn.Module):
    def __init__(self, num_buckets, num_heads, bidirectional, dtype=torch.bfloat16, max_dist=128):
        super(T5RelativeEmbedding, self).__init__()
        self.num_buckets = num_buckets
        self.num_heads = num_heads
        self.bidirectional = bidirectional
        self.max_dist = max_dist

        # layers
        self.embedding = nn.Embedding(num_buckets, num_heads, dtype=dtype)

    def forward(self, lq, lk):
        device = self.embedding.weight.device
        # rel_pos = torch.arange(lk).unsqueeze(0).to(device) - \
        #     torch.arange(lq).unsqueeze(1).to(device)
        rel_pos = torch.arange(lk, device=device).unsqueeze(0) - torch.arange(lq, device=device).unsqueeze(1)
        rel_pos = self._relative_position_bucket(rel_pos)

        rel_pos_embeds = self.embedding(rel_pos)

        rel_pos_embeds = rel_pos_embeds.permute(2, 0, 1).unsqueeze(0)  # [1, N, Lq, Lk]
        return rel_pos_embeds.contiguous()

    def _relative_position_bucket(self, rel_pos):
        # preprocess
        if self.bidirectional:
            num_buckets = self.num_buckets // 2
            rel_buckets = (rel_pos > 0).long() * num_buckets
            rel_pos = torch.abs(rel_pos)
        else:
            num_buckets = self.num_buckets
            rel_buckets = 0
            rel_pos = -torch.min(rel_pos, torch.zeros_like(rel_pos))

        # embeddings for small and large positions
        max_exact = num_buckets // 2
        rel_pos_large = max_exact + (torch.log(rel_pos.float() / max_exact) / math.log(self.max_dist / max_exact) * (num_buckets - max_exact)).long()
        rel_pos_large = torch.min(rel_pos_large, torch.full_like(rel_pos_large, num_buckets - 1))
        rel_buckets += torch.where(rel_pos < max_exact, rel_pos, rel_pos_large)
        return rel_buckets


class T5Encoder(nn.Module):
    def __init__(
        self,
        dtype,
        vocab,
        dim,
        dim_attn,
        dim_ffn,
        num_heads,
        num_layers,
        num_buckets,
        shared_pos=True,
        dropout=0.1,
        cpu_offload=False,
        quantized=False,
        quant_scheme=None,
    ):
        super(T5Encoder, self).__init__()
        self.cpu_offload = cpu_offload
        self.dim = dim
        self.dim_attn = dim_attn
        self.dim_ffn = dim_ffn
        self.num_heads = num_heads
        self.num_layers = num_layers
        self.num_buckets = num_buckets
        self.shared_pos = shared_pos
        self.quant_scheme = quant_scheme

        # layers
        self.token_embedding = vocab.to(dtype) if isinstance(vocab, nn.Embedding) else nn.Embedding(vocab, dim, dtype=dtype)
        self.pos_embedding = T5RelativeEmbedding(num_buckets, num_heads, bidirectional=True, dtype=dtype) if shared_pos else None
        self.dropout = nn.Dropout(dropout)

        if cpu_offload:
            self.weights_stream_mgr = WeightAsyncStreamManager(blocks_num=num_layers)
            self.blocks_weights = T5OffloadBlocksWeights(num_layers, quant_scheme)
            self.blocks = self.blocks_weights.blocks
        else:
            self.blocks = nn.ModuleList(
                [
                    T5SelfAttention(
                        dim,
                        dim_attn,
                        dim_ffn,
                        num_heads,
                        num_buckets,
                        shared_pos,
                        dropout,
                        quantized,
                        quant_scheme,
                        dtype,
                    )
                    for _ in range(num_layers)
                ]
            )

        self.norm = T5LayerNorm(dim, dtype=dtype)

    def forward_without_offload(self, ids, mask=None):
        x = self.token_embedding(ids)
        x = self.dropout(x)
        e = self.pos_embedding(x.size(1), x.size(1)) if self.shared_pos else None

        for i, block in enumerate(self.blocks):
            x = block(x, mask, pos_bias=e)
        x = self.norm(x)
        x = self.dropout(x)
        return x.to(GET_DTYPE())

    def forword_attn_with_offload(self, x, attn_phase, context=None, mask=None, pos_bias=None):
        context = x if context is None else context
        b, n, c = x.size(0), self.num_heads, self.dim_attn // self.num_heads
        # compute query, key, value
        q = attn_phase.attn_q.apply(x.squeeze(0)).view(b, -1, n, c)
        k = attn_phase.attn_k.apply(context.squeeze(0)).view(b, -1, n, c)
        v = attn_phase.attn_v.apply(context.squeeze(0)).view(b, -1, n, c)
        # attention bias
        attn_bias = x.new_zeros(b, n, q.size(1), k.size(1))
        if pos_bias is not None:
            attn_bias += pos_bias
        if mask is not None:
            assert mask.ndim in [2, 3]
            mask = mask.view(b, 1, 1, -1) if mask.ndim == 2 else mask.unsqueeze(1)
            attn_bias.masked_fill_(mask == 0, torch.finfo(x.dtype).min)

        # compute attention (T5 does not use scaling)
        attn = torch.einsum("binc,bjnc->bnij", q, k) + attn_bias
        attn = F.softmax(attn.float(), dim=-1).type_as(attn)
        x = torch.einsum("bnij,bjnc->binc", attn, v)
        x = x.reshape(b, -1, n * c)
        x = attn_phase.attn_o.apply(x.squeeze(0)).unsqueeze(0)
        return x

    def forward_ffn_with_offload(self, x, ffn_phase):
        x = x.squeeze(0)
        x = ffn_phase.ffn_fc1.apply(x) * ffn_phase.gelu(ffn_phase.ffn_gate_0.apply(x))
        x = ffn_phase.ffn_fc2.apply(x)
        return x.unsqueeze(0)

    def forward_block_with_offload(self, block, x, mask=None, pos_bias=None):
        if self.shared_pos:
            e = pos_bias
        else:
            lq, lk = x.size(1), x.size(1)
            rel_pos = torch.arange(lk, device="cuda").unsqueeze(0) - torch.arange(lq, device="cuda").unsqueeze(1)
            num_buckets = block.pos_embedding.weight.shape[0] // 2
            rel_buckets = (rel_pos > 0).long() * num_buckets
            rel_pos = torch.abs(rel_pos)
            max_exact = num_buckets // 2
            rel_pos_large = max_exact + (torch.log(rel_pos.float() / max_exact) / math.log(128 / max_exact) * (num_buckets - max_exact)).long()
            rel_pos_large = torch.min(rel_pos_large, torch.full_like(rel_pos_large, num_buckets - 1))
            rel_buckets += torch.where(rel_pos < max_exact, rel_pos, rel_pos_large)
            e = block.pos_embedding.apply(rel_buckets).permute(2, 0, 1).unsqueeze(0).contiguous()

        norm1_out = block.norm1.apply(x)
        x = fp16_clamp(x + self.forword_attn_with_offload(norm1_out, block.compute_phases[0], mask=mask, pos_bias=e))
        norm2_out = block.norm2.apply(x)
        x = fp16_clamp(x + self.forward_ffn_with_offload(norm2_out, block.compute_phases[1]))
        return x

    def forward_with_offload(self, ids, mask=None):
        self.token_embedding = self.token_embedding.to("cuda")
        self.pos_embedding = self.pos_embedding.to("cuda") if self.pos_embedding is not None else None

        x = self.token_embedding(ids)
        x = self.dropout(x)
        e = self.pos_embedding(x.size(1), x.size(1)) if self.shared_pos else None
        self.norm = self.norm.to("cuda")

        for block_idx in range(len(self.blocks)):
            self.block_idx = block_idx
            if block_idx == 0:
                self.weights_stream_mgr.active_weights[0] = self.blocks[0]
                self.weights_stream_mgr.active_weights[0].to_cuda()

            if block_idx < len(self.blocks) - 1:
                self.weights_stream_mgr.prefetch_weights(block_idx + 1, self.blocks)

            with torch.cuda.stream(self.weights_stream_mgr.compute_stream):
                x = self.forward_block_with_offload(self.blocks[block_idx], x, mask, pos_bias=e)
            self.weights_stream_mgr.swap_weights()

        x = self.norm(x)
        x = self.dropout(x)
        return x.to(GET_DTYPE())

    def forward(self, ids, mask=None):
        if self.cpu_offload:
            return self.forward_with_offload(ids, mask)
        else:
            return self.forward_without_offload(ids, mask)


class T5Decoder(nn.Module):
    def __init__(
        self,
        vocab,
        dim,
        dim_attn,
        dim_ffn,
        num_heads,
        num_layers,
        num_buckets,
        shared_pos=True,
        dropout=0.1,
    ):
        super(T5Decoder, self).__init__()
        self.dim = dim
        self.dim_attn = dim_attn
        self.dim_ffn = dim_ffn
        self.num_heads = num_heads
        self.num_layers = num_layers
        self.num_buckets = num_buckets
        self.shared_pos = shared_pos

        # layers
        self.token_embedding = vocab if isinstance(vocab, nn.Embedding) else nn.Embedding(vocab, dim)
        self.pos_embedding = T5RelativeEmbedding(num_buckets, num_heads, bidirectional=False) if shared_pos else None
        self.dropout = nn.Dropout(dropout)
        self.blocks = nn.ModuleList([T5CrossAttention(dim, dim_attn, dim_ffn, num_heads, num_buckets, shared_pos, dropout) for _ in range(num_layers)])
        self.norm = T5LayerNorm(dim)

        # initialize weights
        self.apply(init_weights)

    def forward(self, ids, mask=None, encoder_states=None, encoder_mask=None):
        b, s = ids.size()

        # causal mask
        if mask is None:
            mask = torch.tril(torch.ones(1, s, s).to(ids.device))
        elif mask.ndim == 2:
            mask = torch.tril(mask.unsqueeze(1).expand(-1, s, -1))

        # layers
        x = self.token_embedding(ids)
        x = self.dropout(x)
        e = self.pos_embedding(x.size(1), x.size(1)) if self.shared_pos else None
        for block in self.blocks:
            x = block(x, mask, encoder_states, encoder_mask, pos_bias=e)
        x = self.norm(x)
        x = self.dropout(x)
        return x


class T5Model(nn.Module):
    def __init__(
        self,
        vocab_size,
        dim,
        dim_attn,
        dim_ffn,
        num_heads,
        encoder_layers,
        decoder_layers,
        num_buckets,
        shared_pos=True,
        dropout=0.1,
    ):
        super(T5Model, self).__init__()
        self.vocab_size = vocab_size
        self.dim = dim
        self.dim_attn = dim_attn
        self.dim_ffn = dim_ffn
        self.num_heads = num_heads
        self.encoder_layers = encoder_layers
        self.decoder_layers = decoder_layers
        self.num_buckets = num_buckets

        # layers
        self.token_embedding = nn.Embedding(vocab_size, dim)
        self.encoder = T5Encoder(
            self.token_embedding,
            dim,
            dim_attn,
            dim_ffn,
            num_heads,
            encoder_layers,
            num_buckets,
            shared_pos,
            dropout,
        )
        self.decoder = T5Decoder(
            self.token_embedding,
            dim,
            dim_attn,
            dim_ffn,
            num_heads,
            decoder_layers,
            num_buckets,
            shared_pos,
            dropout,
        )
        self.head = nn.Linear(dim, vocab_size, bias=False)

        # initialize weights
        self.apply(init_weights)

    def forward(self, encoder_ids, encoder_mask, decoder_ids, decoder_mask):
        x = self.encoder(encoder_ids, encoder_mask)
        x = self.decoder(decoder_ids, decoder_mask, x, encoder_mask)
        x = self.head(x)
        return x


def _t5(
    name,
    encoder_only=False,
    decoder_only=False,
    return_tokenizer=False,
    tokenizer_kwargs={},
    dtype=torch.float32,
    device="cpu",
    **kwargs,
):
    # sanity check
    assert not (encoder_only and decoder_only)

    # params
    if encoder_only:
        model_cls = T5Encoder
        kwargs["vocab"] = kwargs.pop("vocab_size")
        kwargs["num_layers"] = kwargs.pop("encoder_layers")
        _ = kwargs.pop("decoder_layers")
    elif decoder_only:
        model_cls = T5Decoder
        kwargs["vocab"] = kwargs.pop("vocab_size")
        kwargs["num_layers"] = kwargs.pop("decoder_layers")
        _ = kwargs.pop("encoder_layers")
    else:
        model_cls = T5Model

    # init model
    with torch.device(device):
        model = model_cls(dtype=dtype, **kwargs)

    # set device
    model = model.to(device=device)
    return model


def split_block_weights(weights):
    block_weights = {}
    all_keys = list(weights.keys())
    for key in all_keys:
        if key.startswith(("blocks.")):
            block_weights[key] = weights.pop(key)
    return block_weights


def umt5_xxl(**kwargs):
    cfg = dict(
        vocab_size=256384,
        dim=4096,
        dim_attn=4096,
        dim_ffn=10240,
        num_heads=64,
        encoder_layers=24,
        decoder_layers=24,
        num_buckets=32,
        shared_pos=False,
        dropout=0.1,
    )
    cfg.update(**kwargs)
    return _t5("umt5-xxl", **cfg)


class T5EncoderModel:
    def __init__(
        self,
        text_len,
        dtype=torch.bfloat16,
        device=torch.cuda.current_device(),
        checkpoint_path=None,
        tokenizer_path=None,
        shard_fn=None,
        cpu_offload=False,
        t5_quantized=False,
        t5_quantized_ckpt=None,
        quant_scheme=None,
        load_from_rank0=False,
    ):
        self.text_len = text_len
        self.dtype = dtype
        self.device = device
        if t5_quantized_ckpt is not None and t5_quantized:
            self.checkpoint_path = t5_quantized_ckpt
        else:
            self.checkpoint_path = checkpoint_path
        self.tokenizer_path = tokenizer_path

        # sync cpu offload
        self.cpu_offload = cpu_offload

        model = (
            umt5_xxl(
                encoder_only=True,
                return_tokenizer=False,
                dtype=dtype,
                device=device,
                cpu_offload=cpu_offload,
                quantized=t5_quantized,
                quant_scheme=quant_scheme,
            )
            .eval()
            .requires_grad_(False)
        )

        weights_dict = load_weights(
            self.checkpoint_path,
            cpu_offload=cpu_offload,
            load_from_rank0=load_from_rank0,
        )

        if cpu_offload:
            block_weights_dict = split_block_weights(weights_dict)
            model.blocks_weights.load(block_weights_dict)
            del block_weights_dict
            gc.collect()

        model.load_state_dict(weights_dict)
        del weights_dict
        gc.collect()
        self.model = model
        if shard_fn is not None:
            self.model = shard_fn(self.model, sync_module_states=False)
        else:
            self.model.to(self.device)
        # init tokenizer
        self.tokenizer = HuggingfaceTokenizer(name=tokenizer_path, seq_len=text_len, clean="whitespace")

    def infer(self, texts):
        ids, mask = self.tokenizer(texts, return_mask=True, add_special_tokens=True)
        ids = ids.cuda()
        mask = mask.cuda()
        seq_lens = mask.gt(0).sum(dim=1).long()

        with torch.no_grad():
            context = self.model(ids, mask)

        return [u[:v] for u, v in zip(context, seq_lens)]


if __name__ == "__main__":
    import time

    checkpoint_dir = ""
    t5_checkpoint = "./models_t5_umt5-xxl-enc-bf16.pth"
    t5_tokenizer = "./google/umt5-xxl"

    cpu_offload = True
    if cpu_offload:
        device = torch.device("cpu")
    else:
        device = torch.device("cuda")

    model = T5EncoderModel(
        text_len=512,
        dtype=torch.bfloat16,
        device=device,
        checkpoint_path=os.path.join(checkpoint_dir, t5_checkpoint),
        tokenizer_path=os.path.join(checkpoint_dir, t5_tokenizer),
        shard_fn=None,
        cpu_offload=cpu_offload,
    )
    text = "Two anthropomorphic cats in comfy boxing gear and bright gloves fight intensely on a spotlighted stage."

    torch.cuda.synchronize()
    s_t = time.time()
    outputs = model.infer(text)

    torch.cuda.synchronize()
    e_t = time.time()

    logger.info(e_t - s_t)
    logger.info(outputs)