Tokencake: A KV-Cache-centric Serving Framework for LLM-based Multi-Agent Applications

Abstract: LLMs are increasingly deployed in complex multi-agent applications that use external function calls. This workload creates severe performance challenges for the KV Cache: space contention leads to the eviction of critical agents' caches and time underutilization leaves the cache of agents stalled on long-running tool calls idling in GPU memory. We present Tokencake, a KV-Cache-centric serving framework that co-optimizes scheduling and memory management with an agent-aware design. Tokencake's Space Scheduler uses dynamic memory partitioning to shield critical agents from contention, while its Time Scheduler employs a proactive offload and predictive upload mechanism to repurpose GPU memory during function call stalls. Our evaluation on representative multi-agent benchmarks shows that Tokencake can reduce end-to-end latency by over 47.06%, improve effective GPU memory utilization by up to 16.9% compared to vLLM.