>I did some performance tests on gif interfaces on a NetBSD 1.6 system.  I 
>created a number of IPv6 in IPv4 tunnels on a NetBSD host and took a 
>throughput measurement with iperf by sending traffic to only one tunnel. 
>Varying the number of configured tunnels(gif interfaces) on the machines 
>provided very troubling results.

	remove "#define USE_ENCAPCHECK" from sys/netinet/in_gif.c and
	sys/netinet6/in6_gif.c, then you will see a lot better performance.
	(due to the use of radix lookup)

itojun