Poor performance with natd/ipfw and TSO enabled on bce(4) card and 8.1-PRERELEASE

[Garrett Cooper]

On Thu, Jul 1, 2010 at 7:20 PM, Aleksandr A Babaylov <. at babolo.ru> wrote:
> On Thu, Jul 01, 2010 at 04:54:47PM -0700, Pyun YongHyeon wrote:
>> On Wed, Jun 30, 2010 at 07:00:53PM -0700, Garrett Cooper wrote:
>> > Hi,
>> >     Just an observation I made while transferring a file:
>> >
>> > # time scp floppy.img somehost:
>> > Password:
>> > floppy.img                                    100% 1440KB  13.7KB/s   01:45
>> >
>> > real        1m59.400s
>> > user        0m0.031s
>> > sys 0m0.028s
>> > # sysctl net.inet.tcp.tso=0
>> > net.inet.tcp.tso: 1 -> 0
>> > # time scp floppy.img somehost:
>> > floppy.img                                    100% 1440KB   1.4MB/s   00:00
>> >
>> > real        0m0.712s
>> > user        0m0.018s
>> > sys 0m0.018s
>> >
>> >     Going ISDN speeds transferring a 1.44MB file is sad when you have
>> > a gigabit uplink :(... natd seems to be doing a LOT of spinning when
>> > TSO is enabled (it's going up to 73% CPU on a dual-proc quad-core
>> > machine).
>> I would use pf(4) if I have to handle lots of NAT rules.
> Or ipfw nat.
> man ipfw | grep nat

    That uses the kernel module though, and that's horribly broken on
my machine with 8-STABLE/9-CURRENT (see:
http://www.mail-archive.com/freebsd-net@freebsd.org/msg33518.html ). I
wonder if that's related to the TSO issue.
Thanks!
-Garrett