Netmap for routers (em0 device)

Hello

I am very happy to see freebsd could have such network performance with
netmap ,
since I am currently using freebsd as core routers instead of cisco.

I tried to re-compile the freebsd 8.2 kernel to test ,
however , I could not complete the task ( both i386 and amd64 ),
I could only success at 9.0-RC-1.

Here is my task and error message,

cp /usr/src/sys/i386/conf/GENERIC /usr/src/sys/i386/conf/Netmap-Router
echo "device netmap" >> /usr/src/sys/i386/conf/Netmap-Router
cd /tmp/netmap/sys/
cp -R * /usr/src/sys/
cd /usr/src/
patch -p < /tmp/netmap/head-netmap.diff
echo "WITHOUT_MODULES = bge re igb" >> /etc/make.conf
make buildkernel KERNCONF=Netmap-Router
make installkernel KERNCONF=Netmap-Router

-Werror  ../../../dev/e1000/if_em.c -I../../../dev/e1000
../../../dev/e1000/if_em.c: In function 'em_setup_receive_ring':
../../../dev/e1000/if_em.c:4012: error: 'j' undeclared (first use in this
function)
../../../dev/e1000/if_em.c:4012: error: (Each undeclared identifier is
reported only once
../../../dev/e1000/if_em.c:4012: error: for each function it appears in.)
*** Error code 1

Stop in /usr/src/sys/i386/compile/Netmap-Router


Any hint of error message ?

More questions ,
I seldom facing DDOS , whatever using polling or not ,
1Gbps link with 64bytes packet will cause CPU 100% ,
if a freebsd box compile with netmap ,
could it have performance boost of routed / ipfw / pf ?