miniReranker: Efficient Multimodal Reranking through Visual Cache Reuse and Interaction Sparsity

Yingqi Fan, Xuan Lu, Anhao Zhao, Junlong Tong, Ping Nie, Kai Zou, Yunpu Ma, Wei Zhang, Xiaoyu Shen


Abstract
Multimodal large language models (MLLMs) have recently shown strong potential as point-wise rerankers by directly modeling query–document relevance through next-token prediction. However, point-wise reranking suffers from substantial repeated computation across query–document pairs, while the causal structure of transformers allows only prefix segments to be reused via pre-caching. To address the misalignment of existing query-first and document-first formats with both VQA-style prompting and computation-aware reuse, we propose a vision-first formulation that improves both cache reuse efficiency and reranking performance. However, the remaining cost is still considerable and stems from three main sources: (1) *model depth*, for which we reduce active parameters via early exit; (2) *cross-segment attention*, which we restrict to a narrow interaction band across a few layers; and (3) *visual tokens*, where we reduce the number of tokens via embedder-guided pruning. Together, these designs form *miniReranker*, which reduces reranking runtime to <1% of the dense implementation under high-reuse settings for a single query, while preserving >96% of the dense model performance.
Anthology ID:
2026.findings-emnlp.1849
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
39488–39505
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URL:
https://aclanthology.org/2026.findings-emnlp.1849/
DOI:
Bibkey:
Cite (ACL):
Yingqi Fan, Xuan Lu, Anhao Zhao, Junlong Tong, Ping Nie, Kai Zou, Yunpu Ma, Wei Zhang, and Xiaoyu Shen. 2026. miniReranker: Efficient Multimodal Reranking through Visual Cache Reuse and Interaction Sparsity. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 39488–39505, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
miniReranker: Efficient Multimodal Reranking through Visual Cache Reuse and Interaction Sparsity (Fan et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1849.pdf