Cannikin: No Lagger of SLO in Concurrent Multiple LoRA LLM Serving

Low-rank adaptation (LoRA) is widely used to efficiently fine-tune large language models (LLMs), leading to multiple models fine-tuned from the same pre-trained LLM. State-of-the-art LLM serving systems colocate these LoRA models on the same GPU instances for concurrent serving, which decreases memory usage and boosts efficiency. However, the unawareness of the SLO requirements of each LoRA service and the interference between requests from different LoRA services can cause significant SLO violations. This paper presents Cannikin, a multi-LoRA inference serving system that optimizes the minimum of the SLO attainments of all LoRA services in the serving system, denoted as lagger-SLO attainment. We obtain insights from the characterization of a real-world multi-LoRA serving trace, which reveals the stable input/output lengths of the most popular LoRA services. This motivates Cannikin to propose an SLO-aware scheduling algorithm that prioritizes requests based on efficient deadline estimation. Cannikin further detects the influence of interference between different LoRA services on SLO violations and eliminates the bias between these services. The evaluation using real-world traces demonstrates that compared to the state-of-the-art multi-LoRA serving systems, Cannikin can handle up to 3.6× higher rates or 2.8× more burstiness while maintaining the SLO attainment of each LoRA service $> $ 90% .