I tested this a bit ago in Linux just to see how much the difference is between Windows and Linux BBA emulation latencies.
Currently the Linux TAP source only searches for a "Dolphin" TAP device, so only one instance of Dolphin can connect to it.
I have some code to change that so up to four instances of Dolphin can connect to TAP devices, but I have yet to commit it.
The overhead in Linux is nothing, while the overhead in Windows is in the multiple of seconds apparently.
As proof, here is me running four instances of Mario Kart Double Dash on my laptop at full speed. In Windows this would have so much overhead that the games wouldn't even maintain a connection.
Currently the Linux TAP source only searches for a "Dolphin" TAP device, so only one instance of Dolphin can connect to it.
I have some code to change that so up to four instances of Dolphin can connect to TAP devices, but I have yet to commit it.
The overhead in Linux is nothing, while the overhead in Windows is in the multiple of seconds apparently.
As proof, here is me running four instances of Mario Kart Double Dash on my laptop at full speed. In Windows this would have so much overhead that the games wouldn't even maintain a connection.
