thank you luigi for your reply, it helped. i changed the hz parameter to 1000 and then 4000 and then 8000 in my /boot/loader.conf. the result got much better. i configured my system as a router and i send 1GB traffic rate passing by it and set an 800MBytes bandwidth limit on input traffic with dummynet. this was the result: with hz=1 (default) between 200MBytes/s and 300MBytes/s with hz=1000 between 200MBytes/s and 300MBytes/s with hz=4000 between 350MBytes/s and 450MBytes/s with hz=8000 between 250MBytes/s and 550MBytes/s
the maximum traffic rate is got so much better, but 2 problems still remain: 1- the maximum rate is still not high enough. 2- the rate variation range is high (250-550) and it's not a steady enough. i've also tried setting different "queue" and "burst" values for the pipe. the result is a little better when i set "queue" to a value between 80MBytes and 90MBytes and "burst" to a big number. any other ideas? ________________________________ From: Luigi Rizzo <[email protected]> To: bored to death <[email protected]> Cc: freebsd-ipfw <[email protected]> Sent: Thu, June 3, 2010 9:57:33 PM Subject: Re: traffic bandwidth limit with dummynet On Thu, Jun 03, 2010 at 09:29:20AM -0700, bored to death wrote: > hello, > > i'm trying to limit my input traffic bandwidth on freebsd. i used > ipfw+dummynet. without limitation, i have almost 1Gbit/s input traffic > on my system. when i try to limit the bandwidth, it works fine on low > to normal limitation number (up to 450 Mbit/s). > but when i limit my traffic to an amount bigger than 500MBit/s, my > input traffic lowers down to average of 430 MBit/s. no matter what > limitations i set(from 500MBit/s to 1000MBit/s) my input traffic rate > is getting stucked at 430MBit/s. try to run the kernel with higher value of HZ (in /boot/loader.conf kern.hz=4000 and see if the situation improves. I think the symptoms you are seeing depend on the fact that packets are released every 1/HZ seconds probably causing some queue overflow at high packet rates and [relatively] low HZ values. cheers luigi > i suspected low hardware performance, so i tried this on 2 different > systems with freebsd-8.0 and the result is exactly the same. > > my ipfw rules are: > > Code: > ipfw -q flush > ipfw -q add 500 set 1 pipe 1 all from any to any in > ipfw pipe 1 config bw 700Mbit/s > ipfw add 1000 allow all from any to anyso my question is: > 1- is ipfw+dummynet traffic limit control, has performance problem that > cannot limit traffic correctly if limitation number is bigger than > 500MBit/s? > 2- is there any other way (other than ipfw+dummynet) to limit input bandwidth > in freebsd? > > thank you. > > > > _______________________________________________ > [email protected] mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-ipfw > To unsubscribe, send any mail to "[email protected]" _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-ipfw To unsubscribe, send any mail to "[email protected]" _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-ipfw To unsubscribe, send any mail to "[email protected]"
