TCRA-LLM: Token Compression Retrieval Augmented Large Language Model for Inference Cost Reduction

Junyi Liu, Liangzhi Li, Tong Xiang, Bowen Wang, Yiming Qian


Abstract
Since ChatGPT released its API for public use, the number of applications built on top of commercial large language models (LLMs) increase exponentially. One popular usage of such models is leveraging its in-context learning ability and generating responses given user queries leveraging knowledge obtained by retrieval augmentation. One problem of deploying commercial retrieval-augmented LLMs is the cost due to the additionally retrieved context that largely increases the input token size of the LLMs. To mitigate this, we propose a token compression scheme that includes two methods: summarization compression and semantic compression. The first method applies a T5-based model that is fine-tuned by datasets generated using self-instruct containing samples with varying lengths and reduce token size by doing summarization. The second method further compresses the token size by removing words with lower impact on the semantic. In order to adequately evaluate the effectiveness of the proposed methods, we propose and utilize a dataset called Food-Recommendation DB (FRDB) focusing on food recommendation for women around pregnancy period or infants. Our summarization compression can reduce 65% of the retrieval token size with further 0.3% improvement on the accuracy; semantic compression provides a more flexible way to trade-off the token size with performance, for which we can reduce the token size by 20% with only 1.6% of accuracy drop.
Anthology ID:
2023.findings-emnlp.655
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2023
Month:
December
Year:
2023
Address:
Singapore
Editors:
Houda Bouamor, Juan Pino, Kalika Bali
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
9796–9810
Language:
URL:
https://aclanthology.org/2023.findings-emnlp.655
DOI:
10.18653/v1/2023.findings-emnlp.655
Bibkey:
Cite (ACL):
Junyi Liu, Liangzhi Li, Tong Xiang, Bowen Wang, and Yiming Qian. 2023. TCRA-LLM: Token Compression Retrieval Augmented Large Language Model for Inference Cost Reduction. In Findings of the Association for Computational Linguistics: EMNLP 2023, pages 9796–9810, Singapore. Association for Computational Linguistics.
Cite (Informal):
TCRA-LLM: Token Compression Retrieval Augmented Large Language Model for Inference Cost Reduction (Liu et al., Findings 2023)
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PDF:
https://preview.aclanthology.org/nschneid-patch-5/2023.findings-emnlp.655.pdf