[Kernel] Support fused_moe tuning with gemma-4-26B-A4B-it

[CptTZ]

Purpose

Gemma 4 MoE (google/gemma-4-26B-A4B-it) uses different config attribute names (num_experts, top_k_experts, moe_intermediate_size) on its text sub-config, which caused get_model_params() to fail with an AttributeError on the default Mixtral path. This adds a dedicated handler for Gemma4ForConditionalGeneration. Example stacktrace:

Traceback (most recent call last):
  File "/root/benchmark_moe.py", line 1068, in <module>
    main(args)
  File "/root/benchmark_moe.py", line 878, in main
    E, topk, intermediate_size, hidden_size = get_model_params(config)
                                              ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/root/benchmark_moe.py", line 816, in get_model_params
    E = config.num_local_experts
        ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/dist-packages/transformers/configuration_utils.py", line 419, in __getattribute__                                                                 return super().__getattribute__(key)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'Gemma4TextConfig' object has no attribute 'num_local_experts'                                                                                                  Namespace(model='google/gemma-4-26B-A4B-it', tp_size=2, enable_expert_parallel=False, dtype='auto', use_deep_gemm=False, save_dir='./', seed=88, batch_size=[1, 2, 4, 8, 16, 32,

Additianally, this PR added tuned MoE config TP={1/2/4/8} for gemma-4-26B-A4B-it on H200s

Test Plan

WIP

Test Result

WIP

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[gemini-code-assist]

Code Review

This pull request adds support for the Gemma4ForConditionalGeneration architecture in the MoE kernel benchmark by extracting relevant model parameters from the configuration. Feedback suggests extending this support to include the Gemma4ForCausalLM architecture and implementing a more robust way to retrieve the intermediate size using fallbacks to ensure compatibility with different configuration schemas.

[claude]

Claude Code Review

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