routines
This option is only supported on Linux, and is not reloadable. Values above 65536 are lowered to 65536 with a warning.
routines is the number of thread pairs to run that consume from the tun and UDP queues. Currently, this defaults to
1 which means we have 1 tun queue reader and 1 UDP queue reader. Setting this above 1 will set IFF_MULTI_QUEUE
on the tun device and SO_REUSEPORT on the UDP socket to allow multiple queues.
The maximum recommended setting is half of the available CPU cores. It's recommended to set this to a lower value still, to avoid resource starvation.
When set above 1, the reader threads are pinned to CPUs by default; see
tun.pin_threads and tun.cpu_affinity to
control this behavior.