AllToAll performance not improving

Hello DeepEP developers, appreciate the solid works!
I conducted an all-to-all communication performance comparison experiment on 8 H100 nodes, using [Megatron-LM's DeepEP Integration](https://github.com/NVIDIA/Megatron-LM/tree/main/megatron/core/transformer/moe#performance-optimizations).
To eliminate the impact of pipeline parallelism bubbles and focus on comm performances, I use the first pipeline stage (8 layers with first-3-dense) of the DeepSeek V3 model only, instead of the full model.
I ran pretraining experiments with DeepEP enabled/disabled(other configurations are identical), and the throughputs were roughly the same, which is below the expectation.
I collected the nsys profile reports as follows:
DeepEP(with normal kernels) enabled:
DeepEP disabled:
There are no PPs so the SendRecv kernels represent the alltoall kernels.
It seems the combining alltoall comms are faster(13ms->5ms) with DeepEP, but dispatching becomes slower(13ms->16~18ms), and notify_dispatch/cached_notify costs roughly the same time as combining, which makes the e2e throughput not improve.
Any suggestions or insights are appreciated. Thanks!