kern.ipc.nsfbufs not being set at boottime...

[Jason Mealins]

I am currently running 5.4-RELEASE-p7 on a poweredge 2850 and I am trying to tune it for serving a
very high load of mixed static/dynamic content. Being that the webserver I am using takes advantage
of sendfile I was trying to tune it for values of kern.ipc.nsfbufs which according to what little
documentation I can find is supposed to scale along with kern.maxusers. however when I check netstat
-m I get:
0/0/0 sfbufs in use (current/peak/max)

and when trying to set kern.ipc.nsfbufs in /boot/loader.conf to an arbitrarily low value like 1024,
it stil comes up zero at boot. 

I am very new to running amd64 so any help is great. 

as a reference:
kern.ipc.maxusers=512
kern.ipc.nmbcluster=65536

this is a dell poweredge 2850 with 4 gigs of ram and dual 3.0ghz xeons (nocona) running an SMP
generic kernel.

Jason Mealins