<div dir="ltr">Thanks. I made a wrong observation for the last email that I used ping to measure the latency of TCP and was expecting to see a latency explode.<div><br></div><div>So do you know a way to measure the running TCP's packet latency experienced at the qdisc?</div>
<div>Thanks a lot</div><div>-Mo</div><div><br><div><br></div></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">2013/12/5 Anirudh Sivaraman <span dir="ltr"><<a href="mailto:sk.anirudh@gmail.com" target="_blank">sk.anirudh@gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="HOEnZb"><div class="h5">On Thu, Dec 5, 2013 at 2:52 PM, Dong Mo <<a href="mailto:montedong@gmail.com">montedong@gmail.com</a>> wrote:<br>
> Dear List,<br>
> I am trying to make a bufferbloat fairqueue with qdisc and compare that with<br>
> fq_codel.<br>
> However, I am now having some hard time doing it.<br>
><br>
> The commands I am using are:<br>
><br>
> tc qdisc add dev $IFACE root handle 1: htb default 1<br>
> tc class add dev $IFACE parent 1: classid 1:1 htb rate 40mbit<br>
> tc qdisc del dev eth4 parent 1:1 handle 10: sfq perturb 10<br>
><br>
> And sending packet from the sender, where sfq qdisc is set, to the receiver,<br>
> the queuing delay is quite small and is approximately the same as when<br>
> fq_codel enabled.<br>
><br>
> However, if I am not using sfq (only htb set), and send only one flow over<br>
> this link, the delay will explode again.<br>
><br>
> So is sfq here cut off the queue length somehow? How should I make a<br>
> bufferbloat fair queue on linux box using tc qdisc?<br>
><br>
<br>
</div></div>You could start with the fq_codel qdisc and set the codel interval and<br>
target parameters to absurdly large values (say 1000 seconds each) to<br>
simulate a qdisc that has fair queuing but almost never drops a<br>
packet.<br>
<br>
Anirudh<br>
<br>
> Thanks<br>
><br>
> -Mo Dong<br>
><br>
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><br>
</blockquote></div><br></div>