Amazon SageMaker Inference has added prefix-aware routing, a strategy that directs requests sharing the same prompt prefix to the same instance. By doing so, the KV cache for that prefix remains warm, avoiding redundant recomputation across requests.
According to benchmarks cited on Llama 3.1 70B, the approach reduced P50 time-to-first-token by up to 77% and increased KV cache hit rates from roughly 25% to over 80%.
Why it matters
Time-to-first-token is a key latency measure for interactive LLM applications. Reusing warm KV caches instead of recomputing shared prefixes can improve responsiveness and efficiency for workloads with repeated or common prompt structures.
Who should care
Teams deploying large language models on Amazon SageMaker, particularly those running applications with shared prompt prefixes, may find this routing option relevant for reducing latency.