143e1f46d0
### What this PR does / why we need it? Support shared expert DP for deepseek_mtp feature. `shared_expert_dp` requires `SP==True`, with corresponding parameter restrictions. Previously, due to the coupling between `shared_expert_dp` and torchair, and the removal of `deepseek_mtp` in vllm_ascend, shared expert dp of deepseek_mtp was temporarily removed. Currently, by performing the `reduce_scatter` on the input of deepssek_mtp in `mtp_proposer.py`, we ensure that it matches the dimensions of `input_embedding`, and then perform the `all_gather` on the output of mtp. ### How was this patch tested? baseline: <img width="1184" height="692" alt="image" src="https://github.com/user-attachments/assets/9680d53a-7b1d-481a-accc-b8f3dae2b9e3" /> enable shared_expert_dp and multistream_overlap_shared_expert: <img width="1167" height="687" alt="image" src="https://github.com/user-attachments/assets/2531d06b-dfda-4e24-8628-6f4b0f677ddc" /> TPOT: 48ms -> 45.4ms Average TPS per rank: 117.6 -> 126.1 - vLLM version: v0.11.2 - vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.2 --------- Signed-off-by: chenmenglong <chenmenglong1@huawei.com> Signed-off-by: zengran <zengran2@huawei.com> Co-authored-by: zengran <zengran2@huawei.com>