[Bug]: [trtllm-gen fmha] Missing OE2m1 ForGen VarSeqQ32/64/128 kernels + E2M1 hard-gated selector causes high-throughput decode regression

System Info

b300

Who can help?

for q in 8 16 32 64 128; do
n=$(ls cpp/tensorrt_llm/kernels/trtllmGenKernels/fmha/cubin/QkvE4m3OE2m1ForGencubin.cpp 2>/dev/null | grep -E "VarSeqQ${q}Kv128" | wc -l)
echo "Q${q}: ${n}"
done

res
Q8: 24
Q16: 24
Q32: 0
Q64: 0
Q128: 0

https://github.com/vllm-project/vllm/issues/34988

Information

• The official example scripts
• My own modified scripts

Tasks

• An officially supported task in the examples folder (such as GLUE/SQuAD, ...)
• My own task or dataset (give details below)

Reproduction

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Expected behavior

.

actual behavior

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additional notes

https://github.com/vllm-project/vllm/issues/34988

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