[ROCm] [DeepSeekV4] Preliminary Enablement of DeepSeekV4 on ROCm

[tjtanaavllm]

Purpose

This PR supersedes #40871 as it is rebased against #40860 . (On CUDA side, PR #40760 supersedes PR #40871 )

Test Plan

Test Result

Server command:

max_num_seqs=64
max_num_batched_tokens=131072
tensor_parallel_size=4
export HF_HOME=/data/huggingface-cache
export VLLM_ROCM_USE_AITER=1

unset FLATMM_HIP_CLANG_PATH
MODEL=deepseek-ai/DeepSeek-V4-Flash
vllm serve ${MODEL} \
    --host localhost \
    --port 8000 \
    --dtype auto \
    --tensor-parallel-size ${tensor_parallel_size} \
    --max-num-seqs ${max_num_seqs} \
    --distributed-executor-backend mp \
    --trust-remote-code \
    --gpu-memory-utilization 0.40 \
    --moe-backend "triton_unfused" \
    --enforce-eager \
    --tokenizer-mode "deepseek_v4" \
    --async-scheduling

preliminary tests
lm_eval score

MODEL=deepseek-ai/DeepSeek-V4-Flash
lm_eval --model local-completions --model_args model=$MODEL,base_url=http://0.0.0.0:8000/v1/completions,num_concurrent=8,max_retries=10,max_gen_toks=2048 --batch_size auto --tasks gsm8k --num_fewshot 5 --limit 16  --output_path . 2>&1 | tee -a eval-oldforward.log

local-completions ({'model': 'deepseek-ai/DeepSeek-V4-Flash', 'base_url': 'http://0.0.0.0:8000/v1/completions', 'num_concurrent': 8, 'max_retries': 10, 'max_gen_toks': 2048}), gen_kwargs: ({}), limit: 16.0, num_fewshot: 5, batch_size: auto
|Tasks|Version|     Filter     |n-shot|  Metric   |   |Value|   |Stderr|
|-----|------:|----------------|-----:|-----------|---|----:|---|-----:|
|gsm8k|      3|flexible-extract|     5|exact_match|_  |0.875|_  |0.0854|
|     |       |strict-match    |     5|exact_match|_  |0.875|_  |0.0854|

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Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.

[mergify]

Documentation preview: https://vllm--40931.org.readthedocs.build/en/40931/

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @tjtanaavllm.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork