When tun.pin_threads is on and tun.cpu_affinity is unset, pick pin CPUs
from the allowed set that do not service any up physical NIC's MSI vectors
(read-only walk of /sys/class/net/*/device/msi_irqs and
/proc/irq/*/effective_affinity_list). The old allowed[i] default pinned
encrypt threads onto exactly the cores drivers affine their first RX queue
IRQs to; a flow whose RSS queue fired there had NAPI fighting encrypt for
the core (measured 8.4 vs 10.2 Gbps REV bimodality). Falls back to the old
spread, with a log, when there aren't enough IRQ-free CPUs - e.g. drivers
that allocate one queue per core until the admin narrows them (ethtool -L).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* upgrade to yaml.v3
The main nice fix here is that maps unmarshal into `map[string]any`
instead of `map[any]any`, so it cleans things up a bit.
* add config.AsBool
Since yaml.v3 doesn't automatically convert yes to bool now, for
backwards compat
* use type aliases for m
* more cleanup
* more cleanup
* more cleanup
* go mod cleanup
JackDoan