Cosmos: A CXL-Based Full In-Memory System for Approximate Nearest Neighbor Search

Fuente: arXiv
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Main Authors: Ko, Seoyoung, Shim, Hyunjeong, Doh, Wanju, Yun, Sungmin, So, Jinin, Kwon, Yongsuk, Park, Sang-Soo, Roh, Si-Dong, Yoon, Minyong, Song, Taeksang, Ahn, Jung Ho
Format: Preprint
Published: 2025
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author Ko, Seoyoung
Shim, Hyunjeong
Doh, Wanju
Yun, Sungmin
So, Jinin
Kwon, Yongsuk
Park, Sang-Soo
Roh, Si-Dong
Yoon, Minyong
Song, Taeksang
Ahn, Jung Ho
author_facet Ko, Seoyoung
Shim, Hyunjeong
Doh, Wanju
Yun, Sungmin
So, Jinin
Kwon, Yongsuk
Park, Sang-Soo
Roh, Si-Dong
Yoon, Minyong
Song, Taeksang
Ahn, Jung Ho
contents Retrieval-Augmented Generation (RAG) is crucial for improving the quality of large language models by injecting proper contexts extracted from external sources. RAG requires high-throughput, low-latency Approximate Nearest Neighbor Search (ANNS) over billion-scale vector databases. Conventional DRAM/SSD solutions face capacity/latency limits, whereas specialized hardware or RDMA clusters lack flexibility or incur network overhead. We present Cosmos, integrating general-purpose cores within CXL memory devices for full ANNS offload and introducing rank-level parallel distance computation to maximize memory bandwidth. We also propose an adjacency-aware data placement that balances search loads across CXL devices based on inter-cluster proximity. Evaluations on SIFT1B and DEEP1B traces show that Cosmos achieves up to 6.72x higher throughput than the baseline CXL system and 2.35x over a state-of-the-art CXL-based solution, demonstrating scalability for RAG pipelines.
format Preprint
id arxiv_https___arxiv_org_abs_2505_16096
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Cosmos: A CXL-Based Full In-Memory System for Approximate Nearest Neighbor Search
Ko, Seoyoung
Shim, Hyunjeong
Doh, Wanju
Yun, Sungmin
So, Jinin
Kwon, Yongsuk
Park, Sang-Soo
Roh, Si-Dong
Yoon, Minyong
Song, Taeksang
Ahn, Jung Ho
Hardware Architecture
Retrieval-Augmented Generation (RAG) is crucial for improving the quality of large language models by injecting proper contexts extracted from external sources. RAG requires high-throughput, low-latency Approximate Nearest Neighbor Search (ANNS) over billion-scale vector databases. Conventional DRAM/SSD solutions face capacity/latency limits, whereas specialized hardware or RDMA clusters lack flexibility or incur network overhead. We present Cosmos, integrating general-purpose cores within CXL memory devices for full ANNS offload and introducing rank-level parallel distance computation to maximize memory bandwidth. We also propose an adjacency-aware data placement that balances search loads across CXL devices based on inter-cluster proximity. Evaluations on SIFT1B and DEEP1B traces show that Cosmos achieves up to 6.72x higher throughput than the baseline CXL system and 2.35x over a state-of-the-art CXL-based solution, demonstrating scalability for RAG pipelines.
title Cosmos: A CXL-Based Full In-Memory System for Approximate Nearest Neighbor Search
topic Hardware Architecture
url https://arxiv.org/abs/2505.16096