HASS

HASS (Learning Harmonized Representations for Speculative Sampling, ICLR 2025) is a speculative sampling method improved over EAGLE-2 by harmonizing the draft model's objective and context between its training and decoding stages, achieving significant improvements on speedup ratio and acceptance length.

HASS Performance

DeepSeek-R1

		Datasets
		MT-bench		HumanEval		GSM8K		Alpaca		QA		Summarization		Mean
Temperature	Method	Throughput	Speedup	Throughput	Speedup	Throughput	Speedup	Throughput	Speedup	Throughput	Speedup	Throughput	Speedup	Throughput	Speedup
T=0	DeepSeek Vanilla	35.6709	1.00x	35.5978	1.00x	35.6736	1.00x	35.6902	1.00x	35.6730	1.00x	34.4039	1.00x	35.4516	1.00x
	DeepSeek MTP	62.2485	1.75x	67.3626	1.89x	66.3277	1.86x	61.0297	1.71x	62.2504	1.75x	55.5675	1.62x	62.4644	1.76x
	HASS	66.2789	1.86x (+6.47%)	73.6944	2.07x (+9.40%)	71.4170	2.00x (+7.67%)	65.8383	1.84x (+7.88%)	67.4284	1.89x (+8.32%)	61.8689	1.80x (+11.34%)	67.7543	1.91x (+8.47%)
T=1	DeepSeek Vanilla	35.6798	1.00x	34.9864	1.00x	35.0866	1.00x	35.1235	1.00x	35.7631	1.00x	35.0862	1.00x	35.2876	1.00x
	DeepSeek MTP	54.5895	1.53x	58.6345	1.68x	58.9265	1.68x	49.0787	1.40x	53.5941	1.50x	46.1118	1.31x	53.4892	1.52x
	HASS	58.8619	1.65x (+7.83%)	62.0878	1.77x (+5.89%)	65.5968	1.87x (+11.32%)	55.0553	1.57x (+12.18%)	56.0470	1.57x (+4.58%)	49.5268	1.41x (+7.41%)	57.8626	1.64x (+8.18%)

• Evaluations of DeepSeek-R1 are under the SGLang framework, where the batch size is set as 1. DeepSeek Vanilla, DeepSeek MTP, and HASS represent the auto-regressive decoding, speculative sampling with the official MTP of DeepSeek-R1, and speculative sampling with the MTP continually trained with HASS, respectively. Throughput denotes output token throughput and is evaluated by token/s.
• Here, we continually train the MTP with HASS for 2 epochs on the ShareGPT dataset, where the training data is extremely less than the official MTP and the data distribution is inconsistent with that of DeepSeek-R1.
• On 2$\times$8 H800 GPUs, HASS achieves 1.41x-2.07x speedup ratio compared to the auto-regressive decoding, surpassing DeepSeek-R1's official MTP by 8.47% / 8.18% under temperature=0 / 1.

DeepSeek-R1-Distill-Qwen-32B

		Datasets
		MT-bench		HumanEval		GSM8K		Alpaca		QA		Summarization		Mean
Temperature	Method	Speedup	$\tau$	Speedup	$\tau$	Speedup	$\tau$	Speedup	$\tau$	Speedup	$\tau$	Speedup	$\tau$	Speedup	$\tau$
T=0	HASS	3.4115x	4.1052	3.2300x	4.2911	3.4758x	4.9809	3.1918x	3.7738	2.7392x	3.4779	2.9798x	3.7536	3.1714x	4.0638
T=1	HASS	2.8712x	3.7402	2.9311x	3.8658	3.4341x	4.7770	2.7634x	3.5367	2.5586x	3.2654	2.8616x	3.4244	2.9033x	3.7683

• $\tau$ denotes the acceptance length.
• On 2 H800 GPUs, HASS achieves 2.56x-3.48x speedup ratio compared to the auto-regressive decoding.

LLaMA-series models

• On H800 GPU, HASS achieves 2.81x-4.05x speedup ratio compared to the auto-regressive decoding, surpassing EAGLE-2 by 8%-20%.
• Please refer to Tables 1&2 in the paper.

HASS Weights

Base Model	HASS Weights	Base Model	HASS Weights
DeepSeek-R1	HArmonizedSS/HASS-DeepSeek-R1	DeepSeek-R1-Distill-Qwen-32B	HArmonizedSS/HASS-DeepSeek-R1-Distill-Qwen-32B
LLaMA3-Instruct-8B	HArmonizedSS/HASS-LLaMA3-Instruct-8B	LLaMA3-Instruct-70B	HArmonizedSS/HASS-LLaMA3-Instruct-70B
LLaMA2-Chat-7B	HArmonizedSS/HASS-LLaMA2-Chat-7B	LLaMA2-Chat-13B	HArmonizedSS/HASS-LLaMA2-Chat-13B

Reference

@inproceedings{zhang2025learning,
  title={Learning Harmonized Representations for Speculative Sampling},
  author={Zhang, Lefan and Wang, Xiaodan and Huang, Yanhua and Xu, Ruiwen},
  booktitle={International Conference on Learning Representations},
  year={2025}
}

Acknowledgements

This project has been influenced by many excellent projects in the LLM community, such as EAGLE and others.