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Main Authors: Jin, Weisheng, Song, Maojia, Pala, Tej Deep, Chia, Yew Ken, Zadeh, Amir, Li, Chuan, Poria, Soujanya
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2503.23274
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author Jin, Weisheng
Song, Maojia
Pala, Tej Deep
Chia, Yew Ken
Zadeh, Amir
Li, Chuan
Poria, Soujanya
author_facet Jin, Weisheng
Song, Maojia
Pala, Tej Deep
Chia, Yew Ken
Zadeh, Amir
Li, Chuan
Poria, Soujanya
contents As large language models (LLMs) tackle increasingly complex tasks and longer documents, their computational and memory costs during inference become a major bottleneck. To address this, we propose PromptDistill, a novel, training-free method that improves inference efficiency while preserving generation quality. PromptDistill identifies and retains the most informative tokens by leveraging attention interactions in early layers, preserving their hidden states while reducing the computational burden in later layers. This allows the model to focus on essential contextual information without fully processing all tokens. Unlike previous methods such as H2O and SnapKV, which perform compression only after processing the entire input, or GemFilter, which selects a fixed portion of the initial prompt without considering contextual dependencies, PromptDistill dynamically allocates computational resources to the most relevant tokens while maintaining a global awareness of the input. Experiments using our method and baseline approaches with base models such as LLaMA 3.1 8B Instruct, Phi 3.5 Mini Instruct, and Qwen2 7B Instruct on benchmarks including LongBench, InfBench, and Needle in a Haystack demonstrate that PromptDistill significantly improves efficiency while having minimal impact on output quality compared to the original models. With a single-stage selection strategy, PromptDistill effectively balances performance and efficiency, outperforming prior methods like GemFilter, H2O, and SnapKV due to its superior ability to retain essential information. Specifically, compared to GemFilter, PromptDistill achieves an overall $1\%$ to $5\%$ performance improvement while also offering better time efficiency. Additionally, we explore multi-stage selection, which further improves efficiency while maintaining strong generation performance.
format Preprint
id arxiv_https___arxiv_org_abs_2503_23274
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle PromptDistill: Query-based Selective Token Retention in Intermediate Layers for Efficient Large Language Model Inference
Jin, Weisheng
Song, Maojia
Pala, Tej Deep
Chia, Yew Ken
Zadeh, Amir
Li, Chuan
Poria, Soujanya
Computation and Language
As large language models (LLMs) tackle increasingly complex tasks and longer documents, their computational and memory costs during inference become a major bottleneck. To address this, we propose PromptDistill, a novel, training-free method that improves inference efficiency while preserving generation quality. PromptDistill identifies and retains the most informative tokens by leveraging attention interactions in early layers, preserving their hidden states while reducing the computational burden in later layers. This allows the model to focus on essential contextual information without fully processing all tokens. Unlike previous methods such as H2O and SnapKV, which perform compression only after processing the entire input, or GemFilter, which selects a fixed portion of the initial prompt without considering contextual dependencies, PromptDistill dynamically allocates computational resources to the most relevant tokens while maintaining a global awareness of the input. Experiments using our method and baseline approaches with base models such as LLaMA 3.1 8B Instruct, Phi 3.5 Mini Instruct, and Qwen2 7B Instruct on benchmarks including LongBench, InfBench, and Needle in a Haystack demonstrate that PromptDistill significantly improves efficiency while having minimal impact on output quality compared to the original models. With a single-stage selection strategy, PromptDistill effectively balances performance and efficiency, outperforming prior methods like GemFilter, H2O, and SnapKV due to its superior ability to retain essential information. Specifically, compared to GemFilter, PromptDistill achieves an overall $1\%$ to $5\%$ performance improvement while also offering better time efficiency. Additionally, we explore multi-stage selection, which further improves efficiency while maintaining strong generation performance.
title PromptDistill: Query-based Selective Token Retention in Intermediate Layers for Efficient Large Language Model Inference
topic Computation and Language
url https://arxiv.org/abs/2503.23274