Revert "[feat] enable hierarchical mc2 ops on A2 by default (#5300)"

[realliujiaxu]

We'll release 0.13.0 soon. The main branch is freeze. Let's revert the newest change and redo it once 0.13.0 is released.

• vLLM version: release/v0.13.0
• vLLM main: vllm-project/vllm@81786c8

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[gemini-code-assist]

Code Review

This pull request appears to be a revert of a previous feature, likely to stabilize the main branch for an upcoming release. The changes correctly undo the addition of hierarchical communication for MoE operations. However, if my understanding is incorrect and this is actually adding the feature, there is a potential issue in vllm_ascend/utils.py where a function's implementation doesn't match its accompanying comment, which I've detailed in a specific comment. Assuming this is a revert as titled, the changes look correct and complete.

[gemini-code-assist]

The comment for this function specifies that this hierarchical communication optimization is for A2 devices. However, the function implementation does not include a check for the device type. This could lead to this communication path being enabled on other device types if the environment variables are set, which might cause unexpected behavior or performance issues if not supported. To align the implementation with the documentation and prevent potential issues, it's recommended to add a device type check.

Suggested change

	def is_hierarchical_communication_enabled():
	return (os.getenv("HCCL_INTRA_ROCE_ENABLE", "") == "0"
	and os.getenv("HCCL_INTRA_PCIE_ENABLE", "") == "1")
	def is_hierarchical_communication_enabled():
	return (get_ascend_device_type() == AscendDeviceType.A2 and
	os.getenv("HCCL_INTRA_ROCE_ENABLE", "") == "0" and
	os.getenv("HCCL_INTRA_PCIE_ENABLE", "") == "1")