### What this PR does / why we need it?
If one expert handle more than 48 * 8 token, DispatchGmmCombineDecode
may incur acc problem, because a flag is set too early.
> Reason: LocalTensor ubInputRightHalf, ubInputTmp, ubInputRightHalf,
ubQuantF32, ubQuantS32, and ubQuantF16 use the same space with ubAbs, so
only after all of them are free, the copy from gm into ubInputRightHalf
can start, while before this pr,
AscendC::SetFlag<AscendC::HardEvent::V_MTE2>(0) is too early.
This pr sets flag at right time.
More info about this operator, please refer to RFC: issue
https://github.com/vllm-project/vllm-ascend/issues/5476
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
test qwen3-235b eplb with DispatchGmmCombineDecode on a single A3
node(ep16)
| dataset | version | metric | mode | vllm-api-stream-chat |
|----- | ----- | ----- | ----- | -----|
| aime2024 | 604a78 | accuracy | gen | 86.67 |
- vLLM version: v0.13.0
- vLLM main:
2f4e6548ef
Signed-off-by: wangqiankun <wangqiankun13@huawei.com>
e67608041d