1e05c4908f
### What this PR does / why we need it?
#6729 seems to reduce the NPU memory usage of eplb, but actually moves
the buffer allocation of dist.all_gather_into_tensor to
dist.batch_isend_irecv. Therefore, the overall NPU memory usage is not
reduced. This PR completely reduces the memory usage in this part.
### Does this PR introduce _any_ user-facing change?
### How was this patch tested?
Remaining memory of each rank before the repair.
<img width="649" height="99" alt="image"
src="https://github.com/user-attachments/assets/52a67592-e0e8-4f9a-b194-b84cb848c598"
/>
Remaining memory of each rank after the repair.
<img width="641" height="99" alt="image"
src="https://github.com/user-attachments/assets/0bc2e67c-f328-4dea-98af-d7a459fb4876"
/>
Close EPLB.
<img width="543" height="45" alt="image"
src="https://github.com/user-attachments/assets/6dcba19d-4401-44b8-a6d3-c7b35ee983c7"
/>
Memory of weights for each rank.
<img width="648" height="46" alt="image"
src="https://github.com/user-attachments/assets/4db2fd04-98a0-4d26-a026-2e8287102b99"
/>
Estimated memory for EPLB: 15.68 / 48 (layer_num) + 2 * 0.02 = 0.35 GB
- vLLM version: v0.17.0
- vLLM main:
4034c3d32e
Signed-off-by: shenchuxiaofugui <1311027364@qq.com>