VectorLiteRAG: Latency-Aware and Fine-Grained Resource Partitioning for Efficient RAG

Fuente: arXiv
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Main Authors: Kim, Junkyum, Mahajan, Divya
Format: Preprint
Published: 2025
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author Kim, Junkyum
Mahajan, Divya
author_facet Kim, Junkyum
Mahajan, Divya
contents Retrieval-Augmented Generation (RAG) systems combine vector similarity search with large language models (LLMs) to deliver accurate, context-aware responses. However, co-locating the vector retriever and the LLM on shared GPU infrastructure introduces significant challenges: vector search is memory and I/O intensive, while LLM inference demands high throughput and low latency. Naive resource sharing often leads to severe performance degradation, particularly under high request load or large index sizes. We present VectorLiteRAG, a deployment-friendly RAG system that achieves latency-compliant inference without requiring additional hardware resources. VectorLiteRAG introduces a fine-grained GPU resource allocation mechanism based on detailed performance modeling and access pattern analysis. By estimating search latency and query hit rate distributions, it identifies an optimal index partitioning point across CPU and GPU tiers to minimize contention and maximize throughput. Our evaluations show that VectorLiteRAG consistently expands the SLO compliant request rate range across all tested configurations, including both small and large LLMs, and small and large vector databases compared to naive baselines and state of the art alternatives. In the best case, VectorLiteRAG improves the attainable SLO throughput by up to 1.5 times without compromising generation quality or requiring additional compute resources.
format Preprint
id arxiv_https___arxiv_org_abs_2504_08930
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle VectorLiteRAG: Latency-Aware and Fine-Grained Resource Partitioning for Efficient RAG
Kim, Junkyum
Mahajan, Divya
Machine Learning
Retrieval-Augmented Generation (RAG) systems combine vector similarity search with large language models (LLMs) to deliver accurate, context-aware responses. However, co-locating the vector retriever and the LLM on shared GPU infrastructure introduces significant challenges: vector search is memory and I/O intensive, while LLM inference demands high throughput and low latency. Naive resource sharing often leads to severe performance degradation, particularly under high request load or large index sizes. We present VectorLiteRAG, a deployment-friendly RAG system that achieves latency-compliant inference without requiring additional hardware resources. VectorLiteRAG introduces a fine-grained GPU resource allocation mechanism based on detailed performance modeling and access pattern analysis. By estimating search latency and query hit rate distributions, it identifies an optimal index partitioning point across CPU and GPU tiers to minimize contention and maximize throughput. Our evaluations show that VectorLiteRAG consistently expands the SLO compliant request rate range across all tested configurations, including both small and large LLMs, and small and large vector databases compared to naive baselines and state of the art alternatives. In the best case, VectorLiteRAG improves the attainable SLO throughput by up to 1.5 times without compromising generation quality or requiring additional compute resources.
title VectorLiteRAG: Latency-Aware and Fine-Grained Resource Partitioning for Efficient RAG
topic Machine Learning
url https://arxiv.org/abs/2504.08930