Efficient polling multiple RTU devices over two TCP-RTU gateways

[marekm72]

I'm running a setup with many devices on a single long twisted-pair RS485 bus, polled via one TCP-RTU gateway (MikroTik KNOT). This bus spans two separate buildings (house, garage) and I'd like to split it in two shorter parts, and remove the RS485 cable between the buildings as I already have fiber between them. So the master application (running on a Linux VM) will now talk over two different TCP sockets to the two KNOT gateways each handling its own set of RTU slave devices.
What is the recommended way to do this, ideally non-blocking (communicate with the two gateways in parallel), do I need to run multiple processes/threads or is there an easier way with select() etc.?