Support hidden-dim 3072 for gpt-oss + low_latency kernels

[varun-sundar-rabindranath]

gpt-oss model has a hidden-dim of 2880. At the moment, to transmit tensors of [M, 2880] with DeepEP low_latency kernels , we pad it up to 4096 which is too big of a padding.

This PR adds 3072 to the list of low_latency kernels so we may pad up to only 3072 during model execution.

Test

python3 test_low_latency.py --num-processes=2 --hidden 3072
Reserved 2 GPU(s): [7 3] for command execution
Allocating buffer size: 920.127872 MB ...
/dvs/p4/build/sw/rel/gpgpu/toolkit/r12.8/main_nvshmem/src/modules/transport/ibrc/ibrc.cpp:nvshmemt_init:1935: neither nv_peer_mem, or nvidia_peermem detected. Skipping transport.

/dvs/p4/build/sw/rel/gpgpu/toolkit/r12.8/main_nvshmem/src/modules/transport/ibgda/ibgda.cpp:nvshmemt_init:3630: neither nv_peer_mem, or nvidia_peermem detected. Skipping transport.

/dvs/p4/build/sw/rel/gpgpu/toolkit/r12.8/main_nvshmem/src/host/transport/transport.cpp:nvshmemi_transport_init:282: init failed for transport: IBGDA
/dvs/p4/build/sw/rel/gpgpu/toolkit/r12.8/main_nvshmem/src/modules/transport/ibrc/ibrc.cpp:nvshmemt_init:1935: neither nv_peer_mem, or nvidia_peermem detected. Skipping transport.

/dvs/p4/build/sw/rel/gpgpu/toolkit/r12.8/main_nvshmem/src/modules/transport/ibgda/ibgda.cpp:nvshmemt_init:3630: neither nv_peer_mem, or nvidia_peermem detected. Skipping transport.

/dvs/p4/build/sw/rel/gpgpu/toolkit/r12.8/main_nvshmem/src/host/transport/transport.cpp:nvshmemi_transport_init:282: init failed for transport: IBGDA
[rank 0] Dispatch + combine bandwidth: 102.71 GB/s, avg_t=92.09 us, min_t=89.79 us, max_t=94.69 us
[rank 1] Dispatch + combine bandwidth: 102.51 GB/s, avg_t=92.27 us, min_t=89.95 us, max_t=94.46 us
[rank 1] Dispatch bandwidth: 71.05 GB/s, avg_t=45.44 us | Combine bandwidth: 142.25 GB/s, avg_t=43.80 us
[rank 0] Dispatch bandwidth: 68.22 GB/s, avg_t=47.33 us | Combine bandwidth: 148.64 GB/s, avg_t=41.91 us
[rank 1] Dispatch send/recv time: 26.28 + 6.98 us | Combine send/recv time: 21.07 + 9.52 us
[rank 0] Dispatch send/recv time: 43.67 + 7.09 us | Combine send/recv time: 36.00 + 9.58 us

Ref : vLLM PR using gpt-oss with DeepEP Low Latency kernels vllm-project/vllm#25997

[mgoin]

+1 would be great to get this in 🙏