vLLM Introduces Bi-Directional KV Transfer to Optimize TTFT for Multi-Turn Agentic Workloads

1 reports archived1 independent sourcesupdated 10/12/2026, 08:00:00

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vLLM implements bi-directional KV cache transfer in its Prefill-Decode disaggregation architecture to reduce Time To First Token (TTFT) latency for multi-turn agentic workloads. This allows the decode node to return generated token states to the prefill node for reuse, eliminating redundant computation of accumulated context.

LATEST/vLLM implements bi-directional KV cache transfer in its Prefill-Decode disaggregation architecture to reduce Time To First Token (TTFT) latency for multi-turn agentic workloads. This allows the decode node to return generated token states to the prefill node for reuse, eliminating redundant computation of accumulated context.

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vLLM 官方博客T1·Oct 12, 08:0068 pts
vLLM Introduces Bi-Directional KV Transfer to Optimize TTFT for Multi-Turn Agentic Workloads
- Traditional one-way KV transfer forces Prefill nodes to recompute previously generated tokens in multi-turn chats, increasing TTFT latency.
- Bi-directional transfer enables Decode nodes to share full session KV states with Prefill nodes, avoiding redundant computation.
- This optimization is particularly beneficial for complex agent workloads with frequent tool calls and accumulating context.
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