Preble: Efficient Distributed Prompt Scheduling for LLM Serving

ICLR 2025 Conference Submission8281 Authors

26 Sept 2024 (modified: 02 Dec 2024)ICLR 2025 Conference SubmissionEveryoneRevisionsBibTeXCC BY 4.0
Keywords: LLM prefix caching, LLM serving, Distributed systems for ML
TL;DR: This paper proposes Preble, the first distributed LLM serving platform that targets prompt sharing and improves SOTA serving systems by up to 14.5× on average latency.
Abstract: Prompts to large language models (LLMs) have evolved beyond simple user questions. For LLMs to solve complex problems, today’s practices are to include domain-specific instructions, illustration of tool usages, and/or long context such as textbook chapters in prompts. As such, many parts of prompts are repetitive across requests. Recent works propose to cache and reuse KV state of prompts. However, they are all confined to a single- GPU optimization, while production LLM serving systems are distributed by nature. This paper proposes Preble, the first distributed LLM serving platform that targets and op- timizes for prompt sharing. We designed a distributed scheduling system that co-optimizes KV state reuse and computation load-balancing with a new scheduling algorithm and a hierarchical scheduling mechanism. Our evaluation of Preble with real workloads and re- quest arrival patterns on two open-source LLMs shows that Preble outperforms the SOTA serving systems by 1.5× to 14.5× on average latency and 2× to 10× on p99 latency.
Primary Area: infrastructure, software libraries, hardware, systems, etc.
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Submission Number: 8281
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