Hi all,
I am trying to tune tbf qdisc. My upstream configuration is as follows:
tc qdisc add dev $DEV root handle 1: cbq avpkt 1000 bandwidth 100mbit
tc class add dev $DEV parent 1:0 classid 1:1 cbq rate ${UP_RATE}kbit \
allot 1500 prio 5 bounded
tc qdisc add dev $DEV parent 1:1 handle 10: tbf rate ${UP_RATE}kbit \
burst $BURST limit $LIMIT mtu $MTU
tc filter add dev $DEV parent 1:0 protocol ip prio 18 u323 match ip \
dst 0.0.0.0/0 flowid 1:1
I tried several combinations of BURST (from 10KB until there is no pkt
drops at tbf) and LIMIT values (corresponding to latencies of 40ms, 70ms
and 140ms). MTU is set to 1500, the MTU of the link. I tested this
configuration with several combinations of TCP flows and UDP flows
(seperately). However, the best value I got for throughput was about 90%
of UP_RATE.
My question is: is it possible to get better results with tbf, with
throughput values closer to UP_RATE? And what should be changed in the
script above to get it better?
Thanks,
Joana
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On Friday 07 November 2003 18:34, Maria Joana Urbano wrote:> Hi all, > > I am trying to tune tbf qdisc. My upstream configuration is as follows: > > tc qdisc add dev $DEV root handle 1: cbq avpkt 1000 bandwidth 100mbit > tc class add dev $DEV parent 1:0 classid 1:1 cbq rate ${UP_RATE}kbit \ > allot 1500 prio 5 bounded > tc qdisc add dev $DEV parent 1:1 handle 10: tbf rate ${UP_RATE}kbit \ > burst $BURST limit $LIMIT mtu $MTU > tc filter add dev $DEV parent 1:0 protocol ip prio 18 u323 match ip \ > dst 0.0.0.0/0 flowid 1:1 > > I tried several combinations of BURST (from 10KB until there is no pkt > drops at tbf) and LIMIT values (corresponding to latencies of 40ms, 70ms > and 140ms). MTU is set to 1500, the MTU of the link. I tested this > configuration with several combinations of TCP flows and UDP flows > (seperately). However, the best value I got for throughput was about 90% > of UP_RATE. > > My question is: is it possible to get better results with tbf, with > throughput values closer to UP_RATE? And what should be changed in the > script above to get it better?You don''t need a tbf qdisc if you have a bounded class. The traffic is already bounded by the cbq class. Stef -- stef.coene@docum.org "Using Linux as bandwidth manager" http://www.docum.org/ #lartc @ irc.openprojects.net _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/