examples: set socket buffers and raise tun tx_queue (#1928)

* examples: set socket buffers and raise tun tx_queue

* examples: use the default tcp max window for socket buffers

* examples: note buffers are linux only, clarify tx_queue default

* tun: default tx_queue to 5000

examples/config.yml

@@ -135,12 +135,12 @@ listen:
   # superpacket, so the receive scratch is batch * 64KiB per listening socket (~4MiB per routine at the
   # default of 64). Lower this to trade peak per-syscall throughput for memory on constrained hosts.
   #batch: 64
-  # Configure socket buffers for the udp side (outside), leave unset to use the system defaults. Values will be doubled by the kernel
+  # Linux only. Configure socket buffers for the udp side (outside), leave unset to use the system defaults. Values will be doubled by the kernel
   # Default is net.core.rmem_default and net.core.wmem_default (/proc/sys/net/core/rmem_default and /proc/sys/net/core/rmem_default)
   # Maximum is limited by memory in the system, SO_RCVBUFFORCE and SO_SNDBUFFORCE is used to avoid having to raise the system wide
   # max, net.core.rmem_max and net.core.wmem_max
-  #read_buffer: 10485760
-  #write_buffer: 10485760
+  read_buffer: 3412512
+  write_buffer: 3412512
 
   # On Windows only
   # When true, Nebula installs a WFP (Windows Filtering Platform) PERMIT filter scoped to UDP at the listener port.
@@ -262,8 +262,8 @@ tun:
   drop_local_broadcast: false
   # Toggles forwarding of multicast packets
   drop_multicast: false
-  # Sets the transmit queue length, if you notice lots of transmit drops on the tun it may help to raise this number. Default is 500
-  tx_queue: 500
+  # Sets the transmit queue length, if you notice lots of transmit drops on the tun it may help to raise this number. Default is 5000
+  tx_queue: 5000
   # Default MTU for every packet, safe setting is (and the default) 1300 for internet based traffic
   # Anything above 8937, here or on a route below, is capped to 8937 with a warning
   mtu: 1300