### What this PR does / why we need it? This PR aims to fix performance degradation when mtp>1. Since mtp>1 may result in more tokens (i.e. larger batch size) than acl graph maximum batch size, this will cause draft model to run in eager mode. - vLLM version: v0.11.0rc3 - vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.0 --------- Signed-off-by: Zetong Li <slippersss@126.com>