Pruning Large Language Models to Intra-module Low-rank Architecture with Transitional Activations

Bowen Shen, Zheng Lin, Daren Zha, Wei Liu, Jian Luan, Bin Wang, Weiping Wang


Abstract
Structured pruning fundamentally reduces computational and memory overheads of large language models (LLMs) and offers a feasible solution for end-side LLM deployment. Structurally pruned models remain dense and high-precision, highly compatible with further tuning and compression. However, as the coarse-grained structured pruning poses large damage to the highly interconnected model, achieving a high compression ratio for scaled-up LLMs remains a challenge. In this paper, we introduce a task-agnostic structured pruning approach coupled with a compact Transformer architecture design. The proposed approach, named TransAct, reduces transitional activations inside multi-head attention (MHA) and multi-layer perceptron (MLP) modules, while preserving the inter-module activations that are sensitive to perturbations. Hence, the LLM is pruned into an intra-module low-rank architecture, significantly reducing weights, KV Cache and attention computation. TransAct is implemented on the LLaMA model and evaluated on downstream benchmarks. Results verify the optimality of our approach at high compression with respect to both efficiency and performance. Further, ablation studies reveal the strength of activation-guided iterative pruning and provide experimental analysis on the redundancy of MHA and MLP modules.
Anthology ID:
2024.findings-acl.582
Volume:
Findings of the Association for Computational Linguistics: ACL 2024
Month:
August
Year:
2024
Address:
Bangkok, Thailand
Editors:
Lun-Wei Ku, Andre Martins, Vivek Srikumar
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
9781–9793
Language:
URL:
https://aclanthology.org/2024.findings-acl.582
DOI:
10.18653/v1/2024.findings-acl.582
Bibkey:
Cite (ACL):
Bowen Shen, Zheng Lin, Daren Zha, Wei Liu, Jian Luan, Bin Wang, and Weiping Wang. 2024. Pruning Large Language Models to Intra-module Low-rank Architecture with Transitional Activations. In Findings of the Association for Computational Linguistics: ACL 2024, pages 9781–9793, Bangkok, Thailand. Association for Computational Linguistics.
Cite (Informal):
Pruning Large Language Models to Intra-module Low-rank Architecture with Transitional Activations (Shen et al., Findings 2024)
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PDF:
https://preview.aclanthology.org/add_acl24_videos/2024.findings-acl.582.pdf