YueGuobin b155980402
perf: dedicated 500-worker thread pool for ubridge batch I/O
Replace the default asyncio executor (capped at ~32 threads) with a
dedicated ThreadPoolExecutor sized for large-topology parallelism.
When 500 nodes each call _connect_nio, up to 500 OS threads can now
send blocking ubridge commands in parallel — no longer serialised by
either the event loop or a small thread pool.

- ubridge_hypervisor: module-level _ubridge_sync_pool (max_workers=500)
- docker_vm._connect_nio: dispatches to the dedicated pool instead of
  the default executor
2026-08-10 23:11:23 +08:00
..