APB-V: Accelerating Long-Video Understanding via Sequence-Parallelism-aware Approximate Attention

Yuxiang Huang, Mingye Li, Xu Han, Chaojun Xiao, Weilin Zhao, Ao Sun, Ziqi Yuan, Hao Zhou, Fandong Meng, Zhiyuan Liu


Abstract
The efficiency of long-video inference remains a critical bottleneck, mainly due to the dense computation in the prefill stage of Large Multimodal Models (LMMs). Existing methods either compress visual embeddings or apply sparse attention on a single GPU, yielding limited acceleration or degraded performance and restricting LMMs from handling longer, more complex videos. To overcome these issues, we propose APB-V, a sequence-parallel framework with optimized attention that accelerates long-video inference across multiple GPUs. By distributing approximate attention, APB-V reduces computation and increases parallelism, enabling efficient processing of more visual embeddings without compression and thereby improving task performance. System-level optimizations, such as load balancing and fused forward passes, further unleash the potential of APB-V, delivering speedups of 12.72x, 1.70x, and 1.18x over FlashAttn, ZigZagRing, and APB, without notable performance loss.
Anthology ID:
2026.acl-long.90
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
2010–2025
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URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.90/
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Cite (ACL):
Yuxiang Huang, Mingye Li, Xu Han, Chaojun Xiao, Weilin Zhao, Ao Sun, Ziqi Yuan, Hao Zhou, Fandong Meng, and Zhiyuan Liu. 2026. APB-V: Accelerating Long-Video Understanding via Sequence-Parallelism-aware Approximate Attention. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 2010–2025, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
APB-V: Accelerating Long-Video Understanding via Sequence-Parallelism-aware Approximate Attention (Huang et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-long.90.pdf
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