AFD: update DeepSeek support

[hsliuustc0106]

Purpose

This PR corresponds to the RFC vllm-project#22799 and a follow-up PR of vllm-project#25162.

• online serving requests
• AFD for the DeepSeek V2 Lite model as well as a p2p connector for A2E/E2A communication.
• extend the metadata of afd connector so that AFD can work with different hardware (GPU, NPU and more).

This PR is in collaboration with @chopper0126 @CZRZ

Later, we are going to support the following features:

• multi-stage with micro-batch and async sched (compute&comm)
• enable graph mode
• offline serving request in a batch manner
• multi-node support for full deepseek-V3/R1 models on GPU/NPU.

Test Plan

At this stage, we used 4 GTX3090 GPUs to test the feasibility of our implementation. Both attention and FFN sides shard across 2 GPUs.

#attn side

vllm serve <your/model/path>  --tensor_parallel_size=2 --enable_expert_parallel --enforce_eager  --afd-config '{"afd_connector":"p2pconnector", "afd_role": "attention", "num_afd_stages":"1","afd_extra_config":{"afd_size":"2A2F"}}' 

#ffn side

vllm fserver <your/model/path> --tensor_parallel_size=2 --enable_expert_parallel --enforce_eager --afd-config '{"afd_connector":"p2pconnector", "num_afd_stages":"1", "afd_role": "ffn", "afd_extra_config":{"afd_size":"2A2F"}}' 

Test Result

curl -v http://0.0.0.0:8000/v1/chat/completions \
-H 'Content-Type: application/json' \
-d \
'{ "model": "/home/models/DeepSeek-V2-Lite",
"messages": [
          {"role": "user", "content": "1 3 5 7 9 "}
],
"temperature": 0.6,
"repetition_penalty": 1.0,
"top_p": 0.95,
"top_k": 40,
"max_tokens": 20,
"stream": false}' 

By sending a request to the model, we got:

---

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[hsliuustc0106]

@Oliver-ss could you spend some time reviewing the code? the follow-up features will be updated with independent PRs

[jo-pillar]

There seems to be some inconsistency in understanding. According to the content of the paper, the number of attention instances has no correlation with the TP parallel scale, and your configuration here should be 1A1F.

[jo-pillar]

there should be range(attn_size, ffn_size + attn_size)

[zh-lin1]

Hi, where is this moe_comm_method_name field defined for ForwardContext?