Let me know if you think I could improve these values, but, I advise
anyone with a serious NFS deploymant to use something similar to the
following:

kern.ipc.maxsockbuf=2097152
kern.ipc.somaxconn=8192
net.inet.tcp.delayed_ack=1
net.inet.udp.recvspace=65536
net.inet.udp.maxdgram=57344
vfs.nfs.async=1

In my benchmarks, these values were ideal for NFS.

Please send email to seanc@FreeBSD.org with updates or comments on
these values.