From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amit Kucheria Date: Tue, 11 Dec 2001 18:39:05 +0000 Subject: Re: [LARTC] HTB burst, cburst parameters Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: lartc@vger.kernel.org On Tue, 11 Dec 2001, devik wrote: > > Hmm...so if i understand this correctly, 'burst' controls 'rate' and > > 'cburst' controls 'ceil'? >=20 > exactly. >=20 > > Lets say that i am generating bursty fixed length UDP traffic i.e.1470 > > bytes every 5000us. > > Now for a pkt size of 1470 bytes and 'rate' and 'ceil' being 1.536Mbit > > what would be the ideal values of burst and cburst? >=20 > So one 1.5k packet then 5ms pause, other 1.5 packet ... ok ? > It leads to rate cca 1500/5ms =3D 300kBps =3D 2.4mbit. >=20 > Because is exceeds your 1.5mbit rate so that the burst value > is not so important. Just use minimal value: >=20 > burstmin =3D 1.5mbit/8*10ms =3D 2k >=20 > devik Using those parameters puts the cap on my bandwidth real hard, not at all=20 accuate. Infact, my connections go haywire. Here are the results. ----------------------------------------------------------------- testbed16 [30] % sudo ./T1-using-htb TC=3D/usr/bin/tc DEVICE=DEv eth1 BANDWIDTH=BAndwidth 10Mbit LIMITBW=3D1Mbit AVPKT=3Davpkt 1470 SRC=192.168.157.2 DEST=192.168.158.2 tc qdisc add dev eth1 root handle 1: htb tc class add dev eth1 parent 1: classid 1:1 htb rate 1Mbit ceil 1Mbit burst= 2k ----------------------------------------------------------------- testbed16 [32] % showinfo eth1 ---------------------------------- QDISC logs ---------------------------------- qdisc htb 1: dev eth1 r2q 10 default 1 dcache 0 deq_util 1/1000000 deq_rate 0 trials_per_deq 0 dcache_hits 0 Sent 2946644 bytes 2105 pkts (dropped 1209, overlimits 9640)=20 ---------------------------------- CLASS logs ---------------------------------- class htb 1:1 root prio 0 rate 1Mbit ceil 1Mbit burst 2Kb cburst 2Kb=20 Sent 2946644 bytes 2105 pkts (dropped 1209, overlimits 8506)=20 rate 283bps=20 lended: 2105 borrowed: 0 giants: 0 injects: 0 tokens: 15491 ctokens: 15491 ----------------------------------------------------------------- When i increase the burst size to say 100k i get better thruput but still=20 not equivalent to the ceil. Regards, Amit --=20 The statement below is true. The statement above is false. ^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^-^ Amit Kucheria EECS Grad. Research Assistant University of Kansas @ Lawrence (R)+1-(785)-830 8521 ||| (O)+1-(785)-864 7774 ____________________________________________________ _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://ds9a.nl/lartc/