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taobao-mnn/Qwen3.5-2B-Dflash

sourceHugging Faceapache-2.0updated 2mo agoView on Hugging Face
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Model Card

Qwen3.5-2B DFlash Draft Model

A DFlash speculative-decoding draft model for Qwen3.5-2B .

<details open> <summary><b>English</b></summary>

What is DFlash?

DFlash is a lightweight speculative-decoding draft method. Instead of decoding one token at a time, the draft model proposes a whole block of candidate tokens in a single forward pass, conditioned on hidden states captured from several intermediate layers of the target model. The target model then verifies the block in parallel and accepts the longest correct prefix. This lets the system emit multiple tokens per target forward pass while keeping the output identical to greedy target decoding, which speeds up inference when decoding is memory-bandwidth bound.

Model

Base / target modelQwen3.5-2B
MethodDFlash (speculative decoding)
FrameworkSpecForge
Hardware8× AMD MI308X
Training6 epochs
Data~800K samples: a mixture of NVIDIA Nemotron Post-Training Dataset V2 (Nathawani et al., 2025) and CodeAlpaca (Chaudhary, 2023), regenerated with the target model

Files

  • —model.safetensors — draft model weights
  • —config.json — draft model config

Benchmark

Eval config

  • —Backend: sglang
  • —Decoding: greedy, temperature = 0, max_tokens = 2048
  • —Metric: accept length (AL) = Σ completiontokens / Σ verifyct (tokens emitted per target verify pass)

Per dataset

CategoryDatasetAL (block=8)AL (block=16)
MATHgsm8k4.7075.574
math5005.1526.383
aime254.9565.932
CODEhumaneval4.6095.415
mbpp4.5075.301
lcb4.2524.858
CHATmtbench2.8613.185
arenahard3.1133.407
SCIENCE QAgpqa4.0344.519

Overall

blockALaccept rate
84.16345.21%
164.78125.23%

</details>

<details> <summary><b>中文</b></summary>

DFlash 是什么?

DFlash 是一种轻量级的投机解码(speculative decoding)草稿方法。草稿模型不再逐 token 解码,而是借助从目标模型多个中间层捕获的隐状态,在一次前向中一次性提出一整块(block)候选 token;随后目标模型并行校验该 block,并接受最长的正确前缀。因此在保持与目标模型贪心解码完全一致输出的前提下,每次目标前向可产出多个 token ,进而在访存瓶颈时提高推理速度。

模型信息

基座 / 目标模型Qwen3.5-2B
方法DFlash(投机解码)
训练框架SpecForge
硬件8 卡 AMD MI308X
训练轮数6 个 epoch
训练数据约 80 万条样本:NVIDIA Nemotron Post-Training Dataset V2 (Nathawani et al., 2025) 与 CodeAlpaca (Chaudhary, 2023) 的混合集 ; 使用目标模型重新生成

文件说明

  • —model.safetensors — 草稿模型权重
  • —config.json — 草稿模型配置

评测结果

评测配置

  • —后端: sglang
  • —解码: greedy, 温度 = 0, max_tokens = 2048
  • —指标: 接受长度 (AL) = Σ completiontokens / Σ verifyct(每次目标校验前向产出的 token 数)

分数据集

类型数据集AL (block=8)AL (block=16)
数学gsm8k4.7075.574
math5005.1526.383
aime254.9565.932
代码humaneval4.6095.415
mbpp4.5075.301
lcb4.2524.858
对话mtbench2.8613.185
arenahard3.1133.407
科学问答gpqa4.0344.519

总览

blockAL接受率
84.16345.21%
164.78125.23%

</details>