add gatherep select.

[momo609]

What this PR does / why we need it?

add gatherep select.

Does this PR introduce any user-facing change?

How was this patch tested?

• vLLM version: v0.10.1.1
• vLLM main: vllm-project/vllm@e599e2c

[gemini-code-assist]

Code Review

This pull request updates the token dispatcher selection logic for MoE models on Ascend hardware, making it dependent on the SoC version, token count, and expert parallelism size. My review has identified a critical issue where an unsupported SoC version could lead to a runtime error due to an unhandled case. Additionally, I've noted a high-severity maintainability concern regarding a magic number and code duplication for a key capacity parameter. Addressing these points will enhance the code's robustness and clarity.

[gemini-code-assist]

The function does not handle cases where soc_version is not AscendSocVersion.A2 or AscendSocVersion.A3. In such a scenario, the function will implicitly return None, which violates its str return type annotation and will likely cause a TypeError at runtime. To prevent this, you should add a case to handle unsupported SoC versions, for instance by raising a ValueError.

Suggested change

	if soc_version in {AscendSocVersion.A2}:
	if num_tokens <= mc2_tokens_capacity and ep_size >=16:
	return "TokenDispatcherWithMC2"
	else:
	return "TokenDispatcherWithAllGather"
	elif soc_version in {AscendSocVersion.A3}:
	if num_tokens <= mc2_tokens_capacity:
	return "TokenDispatcherWithMC2"
	else:
	return "TokenDispatcherWithAll2AllV"
	if soc_version in {AscendSocVersion.A2}:
	if num_tokens <= mc2_tokens_capacity and ep_size >=16:
	return "TokenDispatcherWithMC2"
	else:
	return "TokenDispatcherWithAllGather"
	elif soc_version in {AscendSocVersion.A3}:
	if num_tokens <= mc2_tokens_capacity:
	return "TokenDispatcherWithMC2"
	else:
	return "TokenDispatcherWithAll2AllV"
	else:
	raise ValueError(f"Unsupported soc_version: {soc_version}")

[gemini-code-assist]

The value 512 used to calculate mc2_tokens_capacity is a magic number, which makes the code harder to understand and maintain. This same calculation is also present in vllm_ascend/worker/model_runner_v1.py at line 369. To improve clarity and avoid potential inconsistencies, this value should be extracted into a named constant and defined in a central location, such as vllm_ascend/ascend_config.py, so it can be reused across the codebase.

[github-actions]

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[codecov]

Codecov Report

❌ Patch coverage is 95.83333% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 72.95%. Comparing base (4c90fa7) to head (195ca4d).
⚠️ Report is 11 commits behind head on main.

Files with missing lines	Patch %	Lines
vllm_ascend/ops/moe_dispatcher/token_dispatcher.py	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2740      +/-   ##
==========================================
- Coverage   72.99%   72.95%   -0.04%     
==========================================
  Files         153      154       +1     
  Lines       21331    21418      +87     
==========================================
+ Hits        15571    15626      +55     
- Misses       5760     5792      +32     

Flag	Coverage Δ
unittests	72.95% <95.83%> (-0.04%)	⬇️

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[momo609]

TODO: this logic will be consolidated with moe_common_method, without relying on environment variable checks.